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Physical Therapy Treatment of TKA: A comparison of
CPM as an adjunct to PT intervention vs solely PT
intervention
By:
Leann Bullock, SPT
Doctoral Candidate
University of New Mexico School of Medicine
Division of Physical Therapy
Class of 2015
Advisor:
James “Bone” Dexter, PT, MA
Printed Name of Advisor: ______________________
Signature: ________________________ Date: ______________
Approved by the Division of Physical Therapy, School of Medicine, University of
New Mexico in partial fulfillment of the requirements for the degree of Doctor of
Physical Therapy.
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Abstract:
Background/Purpose: Osteoarthritis (OA) affects a large population of adults and can lead to disability.
Many times the preferred method of treatment is total knee arthroplasty (TKA). Also, the use of continuous
passive motion (CPM) as an adjunct to physical therapy (PT) status-post (s/p) TKA is common. However
the effectiveness of CPM treatment (tx) has recently been questioned. The purpose of this case report and
evidenced based analysis was to present the findings of the literature review on the effectiveness of CPM
as an adjunct to PT and discuss interventions that were performed with an 82-year-old female, patient A,
who had a primary diagnosis of L knee OA and underwent a L TKA.
Case Description: An 82-year-old female with a primary diagnosis of L knee OA, s/p L TKA, with multiple
comorbidities, including diabetes mellitus type II, hypertension, and hyperlipidemia. Patient A came to
Lovelace Medical Center-Downtown to undergo a L TKA. Her PT diagnosis is Impaired Joint Mobility, Motor
Function, Muscle Performance, and Range of Motion Associated with Joint Arthroplasty (Pattern 4H). She
was seen by physical therapy (PT) on post-operative day 0 (POD 0) to initiate her PT protocol and facilitate
her recovery. She received a CPM machine on POD 0, which was set from 0-45 degrees of knee flexion
and was used 2 hours per day, with knee flexion ROM being increased by 5 degrees, every new CPM
session. She also underwent traditional PT treatment consisting of early (POD 0) mobilization, ROM, and
strengthening.
Prognosis and Outcomes: TKA pts generally have good functional and ROM recovery. Typically, at
Lovelace Medical Center, they are seen for PT treatment twice a day for 30 minute sessions, until
discharge (d/c), which usually occurs on POD 2 or 3, depending on pt’s comorbidities and functional status.
Patients are usually discharged ambulating with an assistive device, generally a front-wheeled walker
(FWW), and they undergo continued physical therapy, either in an inpatient rehab facility, outpatient clinic,
or at home, until they have achieved their PT goals, which usually consist of ambulating without an
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assistive device, achieving adequate ROM for functional tasks, or reaching prior level of function. Patient A
was discharged to a skilled nursing facility (SNF) with a FWW, due to inability to perform ADLs, transfers,
and ambulation in a sufficient manner to return home with her elderly sister.
Discussion: The use of CPM is controversial, and there is conflicting evidence as to the efficacy of this
treatment and whether it improves outcomes as opposed to traditional PT treatment alone. Therefore, a
literature review was performed to examine the current evidence about CPM treatment and whether or not
it is an effective and worthwhile adjunct to traditional PT treatment in any of the settings it is typically used.
Section 1:
Background and Purpose
TKA is a common treatment for OA, and studies have shown that early mobilization s/p TKA leads
to further increases in ROM. Adequate knee ROM, particularly in flexion, is needed for ambulation and
activities of daily living (ADLs). Therefore, in order to increase functional outcomes, the use of early
mobilization s/p TKA has become standard, and the use of CPM as an adjunct to PT may be part of this
early mobilization. CPM is an external motorized machine that passively moves the joint through a predetermined ROM. It was first introduced in the 1970s by Salter, who demonstrated that CPM tx enhanced
cartilage healing (Brosseau et al., 2004). .
The use of CPM as an adjunct to traditional PT s/p TKA has grown rapidly since the 1980s and
reported benefits of CPM tx include improvements in range of motion (ROM), decreased pain and swelling,
decreased need for manipulation under anesthesia, decreased hospital length of stay (LOS), and a
reduction in overall healthcare costs. These reported benefits are inconclusive, though, because the
literature on CPM has not agreed on these results, since the initial studies by Salter and colleagues (Boese
et al., 2014).
The effectiveness of CPM s/p TKA has been studied with a large variety of protocols. Knee flexion
ROM is generally the primary outcome measure, and while most studies agree on the lack of efficacy of
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long-term CPM for knee flexion ROM, there is still controversy regarding the short-term effectiveness
(Denis et al., 2006).
Thus, the question was formed: In patients who have undergone TKA does PT intervention plus
CPM use vs PT intervention alone cause greater improvements in outcome measurements (ROM, pain,
LOS, AD use, functional status, etc.)? The purpose of this case report and evidenced based analysis was
to present the findings of the literature review on the effectiveness of CPM as an adjunct to PT and discuss
interventions that were performed with an 82-year-old female, patient A, who had a primary diagnosis of L
knee OA and underwent a L TKA.
Patient Information
The patient of interest was an 82 year old female, who will be referred to as Patient A throughout
this case report. Patient A had a primary diagnosis of L knee OA with multiple comorbidities including:
diabetes mellitus type II, hypertension, and hyperlipidemia. She came to Lovelace Medical Center to
undergo a L TKA. She was seen by physical therapy starting on POD 0 and was also started on a CPM
protocol on POD 0.
PICO Question
In patients who have undergone TKA does PT intervention plus CPM use vs PT intervention alone
cause greater improvements in outcome measurements (ROM, pain, LOS, AD use, functional status, etc.)?
Total knee arthroplasty is most commonly performed on patients with a diagnosis of arthritis, either
osteoarthritis (OA) or rheumatoid arthritis (RA). Proper rehabilitation is needed to provide patients with the
best outcomes following surgery. Continuous passive motion machines are often added as an adjunct to
traditional PT treatment, in an effort to improve knee ROM and function. The primary impairments in
patients s/p TKA are decreased ROM, strength, and functional status and increased pain and percentage
of assistive device use.
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CPM is a machine that passively moves the knee to improve ROM, following TKA. However, the
benefits of this treatment have not been proven to be effective. Most studies have not shown any long-term
benefit of the use of CPM as an adjunct therapy. However, the results of CPM use on short-term outcomes
has been controversial (Maniar, 2012). Therefore, this literature review and case study seeks to synthesize
the literature and reach a conclusion on the effect of the use of CPM on functional outcomes following TKA.
Section 2: Case Description
Introduction:
Patient A is an 82-year-old female with a primary diagnosis of L knee OA, s/p L TKA, with multiple
comorbidities, including diabetes mellitus type II, hypertension, and hyperlipidemia. Patient A came to
Lovelace Medical Center-Downtown to undergo a L TKA. She lived in New Jersey, but she elected to
undergo her TKA at Lovelace, due to the fact that her sister lives in Albuquerque. Therefore, she expected
to stay with her sister while undergoing her recovery. Her PT diagnosis is Impaired Joint Mobility, Motor
Function, Muscle Performance, and Range of Motion Associated with Joint Arthroplasty (Pattern 4H). She
was seen by physical therapy (PT) on post-operative day 0 (POD 0) to initiate her PT protocol and facilitate
her recovery. She received a CPM machine on POD 0, which was set from 0-40 degrees of knee flexion
and was used 2 hours per day, with knee flexion ROM being increased by 5 degrees, every new CPM
session. She also underwent traditional PT treatment consisting of early (POD 0) mobilization, ROM, and
strengthening.
At initial evaluation, on POD 0, pt presented with decreased sensation and L knee ROM. She was
unable to weight bear on her L LE for > 3 minutes without experiencing buckling. She was unable to take
steps, due to L knee buckling. She also presented with nausea and vomiting, secondary to pain medication.
Her pain rating on visual analog scale (VAS) was 8/10. While working with PT, Patient A was a 2 person
maximum assist for bed mobility. She was assisted to sitting at edge of bed. She was also assisted to
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standing, but she could not stand for >3 minutes, due to knee buckling; therefore, gait (gt) activities were
not attempted.
When she was seen on POD 1, she was a 2 person maximum (max) assist (A) for bed mobility,
transfers, and gait. Her CPM machine was set from 0-50 degrees, 2 x 1 hour per day. She ambulated 2 x
2.5 feet, with a 1 minute standing rest break, before her knee buckled, and she was placed in a chair. Her L
knee ROM was 63 degrees of PROM flexion and 10 degrees from neutral extension. She was given a
towel roll to place under her heel, while sitting in the chair and in bed, to help her increase her knee
extension. She was instructed to do this 3 times 20 minutes per day. Patient A was seen by the physical
therapy assistant on POD 2, and on POD 3, she was transferred to a skilled nursing facility, due to her
limited mobility and ability to care for herself at home.
Examination:
History:
Patient A was an 82-year-old female admitted to the hospital 11/24/14 to undergo elective TKA, for
a primary diagnosis of L knee OA. She lived alone in New Jersey, so she elected to come to Albuquerque,
NM, for her TKA, so she could stay with her sister, while recovering from surgery. Patient A had insurance,
was retired and was independent in all ADLs and IADLs, prior to surgery. She did not use an assistive
device for mobility, prior to surgery. Her past medical history included: diabetes mellitus type II,
hypertension, and hyperlipidemia. Medications included: Metformin, hydrochlorothiazide and Lisinopril, and
simvastatin. Patient was cognitively intact and fully oriented. Patient’s reported that she would like to return
home with her sister after discharge from the hospital, but she understood that a SNF stay may be
necessary because her sister was not physically capable of providing her with much assistance. Her goals
and expectations were to improve her knee function and ROM.
Systems Review:
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Neuromuscular: Patient A did not present with any neuromuscular signs or symptoms.
Musculoskeletal: Patient A presented with decreased strength, ROM, and sensation in L LE, due to
surgery. Her sensation is intact to light touch. However, proprioception is decreased, leading to buckling of
LE.
Integumentary: Patient A presents with dressing covering her incision on L LE and a drain. Otherwise,
integumentary system is intact.
Cardiopulmonary: Patient A does not present with any cardiopulmonary signs or symptoms.
Tests & Measurements:

ROM:
o R LE: within functional limits (WFL)
o L LE: WFL, except: PROM knee flexion: 63 degrees; PROM knee extension: 10 degrees
from neutral

Strength/MMT:
o R LE: WFL
o L LE: decreased secondary to surgery


2/5, knee flexion and extension
Pain:
o 8/10 on VAS (POD 0 and 1)

Sensation:
o R LE: WFL
o L LE: impaired light touch, deep pressure and proprioception, secondary to surgery and
nerve block

Bed Mobility:
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o 2 person max A from PT for rolling and supine to sit at edge of bed.

Transfers:
o 2 person max A for sit to stand

Ambulation:
o Unable to ambulate POD 0, secondary to decreased sensation, strength and nausea
o Required front-wheeled walker, and 2 person mod A for facilitation of weight shift and
maintaining balance.
o Required verbal cues for assistive device training.
o 2 x 2.5 feet (POD 1) with a 1 minute standing rest break, before her knee buckled and she
was placed in a chair.
Evaluation:
Diagnosis:
Patient A has a medical diagnosis of L knee OA and primary TKA. ICD 9 code V43.65. Her PT
diagnosis, according to the Guide to Physical Therapist Practice is: Impaired Joint Mobility, Motor Function,
Muscle Performance, and Range of Motion Associated with Joint Arthroplasty (Pattern 4H).
Narrative Assessment:
Patient A was an 82-year-old single, female with a primary diagnosis of L knee OA. She was
admitted to Lovelace Medical Center for L TKA. She presented with multiple comorbidities, including
diabetes mellitus type II, hypertension, and hyperlipidemia. She lived alone in New Jersey, but she elected
to undergo her TKA at Lovelace, due to the fact that her sister lives in Albuquerque. Therefore, she
expected to stay with her sister while undergoing her recovery. Her L TKA left her with impairments
requiring physical therapy including impaired ROM, strength, proprioception, endurance, balance, and gait
deviations. These impairments were a result of the trauma obtained during surgery, pain, and edema. They
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left patient A with impaired functional mobility, compared to her prior level of function (PLOF). She had an
elderly sister, who could provide her with some support. However, to return to her sister’s home safely, the
patient needed to demonstrate the ability to safely ambulate household distances (about 100 feet) with her
front-wheeled walker (FWW), negotiate 3 stairs to the front door, and require minimum assistance (less
than 25%) for her activities of daily living (ADLs). Her barriers to successful rehabilitation included: multiple
comorbidities, low pain tolerance, low endurance, decreased family/caregiver support. Her facilitators to
successful rehabilitation included: prior level of function, intact cognition, and motivation. Overall, Patient A
had a good prognosis for successful outcomes and functional recovery with physical rehabilitation s/p TKA.
Clinical Judgments and Problem List:
Problem List:

Decreased Range of Motion
o L knee ROM: 63 degrees of PROM flexion and 10 degrees from neutral extension.
o Unable to climb stairs
o Unable to achieve normal gait

Decreased endurance and activity tolerance
o Unable to ambulate >2. 5 feet without stopping
o 8/10 pain with movement

Decreased strength
o Unable to perform independent bed mobility
o Unable to climb stairs
o Unable to transfer independently
o Unable to ambulate independently, even with FWW

Balance deficits
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o Increased risk for falls

Gait deviations
o May lead to other impairments and pain further up/down the chain due to compensatory
motions
The problems and functional limitations mentioned above will hinder Patient A’s ability to be
discharged home with her sister. She must demonstrate the ability to safely ambulate household distances
(about 100 feet) with her front-wheeled walker (FWW), negotiate 3 stairs to the front door, and require
minimum assistance (less than 25%) for her activities of daily living (ADLs), in order to be discharged
home. At this point in her rehabilitation, she was maximum assistance by 2 people for bed mobility,
transfers, and ambulation with a FWW. She was not able to ambulate community distances or navigate
obstacles, such as curbs or stairs. Therefore, a stay in a skilled nursing facility was considered in order to
provide her with the necessary functional mobility to safely navigate her home environment.
Prognosis:
Prognosis and rehabilitation potential: good.
Goals:

Pt will perform bed mobility on a flat bed, with supervision, by discharge to home, in order to assist
with independence in daily activities.

Pt will perform sit to stand transfer, with supervision and using FWW, by discharge to home, in
order to assist with independence in daily activities.

Pt will ambulate 100 feet with supervision, using FWW, by discharge to home, in order to assist
with household ambulation.

Pt will safely negotiate up/down 3 stairs, with supervision, using FWW, by discharge home, in order
to access her front door.
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Plan of Care:
Patient was scheduled to receive physical therapy treatment 2 x 30 minutes per day every day,
while in the hospital. Interventions included: gait training, manual therapy, neuromuscular re-education,
therapeutic activity, and therapeutic exercise, to assist with return to prior level of function and aid in her
meeting goals.
Interventions:
Physical therapy interventions included utilization of gait training, manual therapy, neuromuscular
re-education, therapeutic activity, and therapeutic exercise to aid Patient A in meeting her goals. Also,
Patient A received a CPM machine which was set from 0-40 degrees, 2 x 1 hour per day. Each new CPM
session, the flexion was increased by 5 degrees to patient tolerance. Patient A was also given a towel roll
to place under her heel, while sitting in the chair and in bed, to help her increase her knee extension. She
was instructed to do this 3 times 20 minutes per day. Patient education on the importance of full knee ROM
and functional mobility was provided. Also, patient was educated on the importance of getting out of bed
and sitting upright to aid in respiratory function, healing, and endurance. She was given a handout of bed
exercises to perform in order to increase her ROM and strength. Treatment plans were adjusted and
progressed to the patient’s tolerance and level of function that day. In summary, the initial interventions
focused on reducing edema, pain, and increasing ROM and function, so more progressive interventions
could be performed.
Outcomes:
Patient A was discharged after she became medical stable. She made progress toward her goals
but did not meet the set goals before discharge from the hospital. She was seen by PT on POD 0 and 1
and by the physical therapy assistant on POD 2. On POD 3, she was transferred to a skilled nursing facility,
due to her limited mobility and inability to care for herself at home. She received traditional PT intervention
plus CPM in the acute care setting, and it was assumed that she would also receive traditional PT plus
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CPM in the SNF. Prior to d/c, she was educated on the importance of increasing her out of bed activities,
ROM, and strength, in order to achieve modified independence in her ADLs and IADLs. She was also
provided assistive device training, so she was able to use her FWW properly.
Section 3. Evidence Based Analysis
Methodologies of Search:
Search methods were determined by the PICO question: In patients who have undergone TKA
does PT intervention plus CPM use vs PT intervention alone cause greater improvements in outcome
measurements (ROM, pain, LOS, AD use, functional status, etc.)? Search methods are outlined in figure 2,
below. Search terms were determined by PICO question and other related terms. They included: total knee
arthroplasty, physical therapy, CPM. Databases searched included: PubMed, CINAHL, Cochrane and Web
of Knowledge. The search yielded ten appropriate articles to appraise, in order to answer the PICO
question. These articles were appraised using forms adopted from the Guide to Evidence-Based Therapist
Practice (see appendix).
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Articles Analyzed:
Herbold, J. A., Bonistall, K., Blackburn, M., Agolli, J., Gaston, S., Gross, C., …Babyar, S. (2014).
Randomized controlled trial of the effectiveness of continuous passive motion after total
knee replacement. Archives of Physical Medicine and Rehabilitation, 95, 1240-5. doi:
http://dx.doi.org/10.1016/j.apmr.2014.03.012
Level of Evidence (Oxford Scale): 1b
Purpose: The purpose of this study was to determine the effects of using a CPM device for patients with
poor ROM s/p TKR, who were admitted for post-acute rehabilitation.
Methods: Patients were transferred directly to the IRF within 5 days of their TKA. They were assigned a
primary therapist, who assessed their AROM knee flex and ext on day 1. Patients were randomly assigned
to the control or treatment group. Control group received conventional PT, and experimental group received
conventional PT and daily CPM application for 2 hours. The pts and therapists were not blinded to the
study group. Conventional therapy included 3 hours per day of PT and OT. CPM machine for the
experimental group was set at flexion tolerance and 0 degrees extension. During the initial PT evaluation,
pts were assessed on study variables. D/C destination and date were set by blinded assessors, and on the
day prior to d/c, the outcome variables were re-assessed. One week after d/c, the WOMAC was mailed to
pt’s home. Outcome measurements were: AROM, TUG score, knee girth, total FIM scores, ambulation
device at d/c, LOS, and self-reported WOMAC scores.
Results: All subjects, in both the CPM and non-CPM groups, significantly improved from admission to the
IRF to discharge in all outcome measures. However, there was no statistically significant differences in any
of the discharge outcome measures of the CPM group compared to the non-CPM group.
Critique/Bottom Line: The results of this study conclude that CPM does not provide additional benefit over
the conventional PT interventions used in an IRF for pts s/p TKR, specifically in patients with poor initial
knee flexion ROM after surgery.
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Boese, C. K., Weis, M., Phillips, T., Lawton-Peters, S., Gallo, T., & Centeno, L. (2014). The efficacy of
Continuous passive motion after total knee arthroplasty: a comparison of three protocols.
The Journal of Arthroplasty, 29, 1158-1162. http://dx.doi.org/10.1016/j.arth.2013.12.005
Level of Evidence (Oxford Scale): 2b
Purpose: The purpose of this study was to evaluate the effects of early aggressive CPM and fixed flexion
proceeding progressive CPM on short-term outcomes compared to standardized PT alone.
Methods: Patients (n=160) were randomly allocated into 1 of 3 groups: CPM device on and moving from
the immediate post-operative period (n=55), CPM device on and stationary at 90 degrees of flexion for first
night and then moving throughout the rest of their stay (n=51), and no CPM (n=54). Pts were then
assessed during their acute care stay on POD 1 and 2 and until their first follow-up appointment,
approximately 3-4 weeks s/p TKA. Cost of CPM was further evaluated. With the exception of CPM, pts
received the same PT protocol, which is listed in article. Outcome measures were: change in hemoglobin
from pre-op til POD 1 and 2; self-reported pain scores on VAS; girth measurements; hospital LOS, and
AROM and PROM flex and ext.
Results: There were no significant differences between the groups for any of the outcome variables.
Critique/Bottom Line: The results of this study conclude that CPM provided no benefit to patients in hospital
s/p TKA in all outcome variables. There were no clinically or statistically significant differences in ROM,
swelling, blood loss, pain scores, or AROM between any of the groups at any of the follow-up time periods.
This study does not find any benefit to using CPM in the acute care setting with pts s/p TKA. Also, this
study claims that discontinuing CPM use in the acute care setting would be an excellent way to decrease
hospital costs, which would transfer to improved pt care.
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Bruun-Olsen, V., Heiberg, K. E., & Mengshoel, A. M. (2009). Continuous passive motion as an adjunct to
active exercises in early rehabilitation following total knee arthroplasty-a randomized controlled
trial. Disability and Rehabilitation 31 (4), 277-283. doi: 10.1080/09638280801931204
Level of Evidence (Oxford Scale): 1b
Purpose: The purpose of this study was to examine whether CPM as an adjunct to active exercises had
any short-term effects (after 1 week and 3 months) on pain, ROM, timed walking and stair climbing.
Methods: A single-blind RCT was conducted with a total of 63 pts, who underwent TKA at Asker and
Baerum General Hospital between Oct 2003 and March 2005, and were randomly assigned into either the
experimental group receiving CPM and active exercises or the control group receiving active exercises
only. Outcomes were measured via a goniometer, VAS, TUG test, timed 40 m walking and timed stair
climbing. Active exercises were performed daily from POD 1 in 30 minute sessions and adjusted to pt
tolerance. The exercise list is included in the article. CPM protocol: POD 0 70-100 deg flex 2 h x2. POD1 )
deg-100 deg, 2 h x 3. All pts stayed in hospital for 7 days.
Results: There were no statistically significant differences between the groups for any of the outcome
variables at 1 week or 3 months. All subjects had a significant and 50% reduction in pain score at 3 mos
(p<0.01). Also, at 3 months all groups had a significantly impaired knee flexion ROM (p<0.01) and a
significantly decreased number of subjects were able to climb stairs (p<0.01).
Critique/Bottom Line: The results of this study conclude that CPM provided no benefit to patients in hospital
s/p TKA in all outcome variables, as compared to active physical therapy alone. 3 months after surgery, all
pts had significant pain relief; however, they still had not reached pre-operative ROM and number of pts
able to climb stairs decreased. This study does not find any benefit to using CPM in the acute care setting
with pts s/p TKA.
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Denis, M. , Helene, M. , Caron, F. , Ouellet, D., Paquet, J., & Nolet, L. (2006). Effectiveness of continuous
Passive motion and conventional physical therapy after total knee arthroplasty: a randomized
Clinical trial. Physical Therapy, 86 (2), 175-185. http://ptjournal.apta.org/content/86/2/174.long
Level of Evidence (Oxford Scale): 1b
Purpose: The purpose of this RCT was to compare the effectiveness of 3 in-hospital rehabilitation programs
with and without continuous passive motion (CPM) for knee flexion and extension ROM, functional ability,
and LOS, after primary TKA.
Methods: A single-blind RCT was conducted with a total of 81 pts, who underwent TKA for a diagnosis of
OA. The subjects were recruited from a hospital in Quebec, if they met inclusion criteria and did not meet
exclusion criteria. The study evaluated the use of CPM protocols in the hospital setting. The subjects were
randomly assigned to 1 of 3 groups immediately after TKA: a control group, which received conventional
PT intervention only; experimental group 1, which received conventional PT and 35 minutes of CPM
application daily; and experimental group 2, which received conventional PT and 2 hours of CPM
application daily. All subjects were evaluated prior to TKA and at d/c. Outcome measurements were AROM
knee flexion and extension, TUG, WOMAC, and LOS.
Results: There were no statistically significant differences between the groups for any of the outcome
measures at discharge.
Critique/Bottom Line: The results of this study do not support the addition of CPM treatment to conventional
PT in the hospital setting s/p TKA because the addition of CPM did not further reduce knee impairments or
disability or reduce the length of hospital stay. This study does not find any benefit to using CPM in the
acute care setting with pts s/p TKA.
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Maniar, R. N., Baviskar, J. V., Singhi, T., & Rathi, S. S. (2012). To use or not to use continuous passive
Motion post-total knee arthroplasty. The Journal of Arthroplasty 27 (2), 193-201. doi:
10.1016/j.arth.2011.04.009
Level of Evidence (Oxford Scale): 1b
Purpose: The purpose of this study was to evaluate in a prospective, randomized manner the effect of CPM
in the hospital setting, compared to traditional PT only, by assessing specific parameters. This study also
hypothesizes that CPM may be useful in initializing knee flexion so that further AROM and PROM training
becomes easier and better tolerated.
Methods: A RCT was conducted with pts of a single surgeon over a period of 3 months. Subjects were
asked to participate if they met inclusion and did not meet exclusion criteria. Subjects were assessed prior
to TKA and again at days 3, 5, 14, 42, and 90 s/p TKA. Subjects were randomly assigned, using concealed
envelopes, to 1 of 3 groups: 1) control group, which received traditional PT only; 2) 1-day-CPM group,
which received conventional PT and 2 CPM applications of 15 minutes each on day 2 after TKA; and 3) 3day-CPM group, which received conventional PT and 2 CPM applications of 15 minutes each daily for 3
days. CPM protocol began with 0-30 deg range and increased by 10 degrees every 5 mins to pt’s
tolerance. The final range of movement became the starting range for the next session. Outcome
measures: pain on VAS, AROM of knee, TUG values, suprapatellar and calf girths, WOMAC and SF-12
scores, and wound healing.
Results: There were no statistically significant differences between the groups for any of the outcome
measurements pre-operatively and s/p on days 3, 5, 14, 42, and 90.
Critique/Bottom Line: The results of this study do not support the addition of CPM treatment to conventional
PT in the hospital setting s/p TKA because CPM provided no benefit in functional recovery or ROM. There
was an indication of better pain relief with 1 day CPM; therefore, indications of using a CPM would be for 1
day to reduce pain.
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Lenssen, T. , Van Steyn, M. , Crijns, Y. , Waltje, E. , Roox, G. M. , Geesink, R. , . . . De Bie, R. (2008).
Effectiveness of prolonged use of continuous passive motion (CPM), as an adjunct to
Physiotherapy, after total knee arthroplasty. BMC Musculoskeletal Disorders, 9 (60), 1471-1274.
doi: 10.1186/1471-2474-9-60
Level of Evidence (Oxford Scale): 1b
Purpose: The purpose of this RCT was to investigate the effectiveness of prolonged CPM use in the home
situation as an adjunct to standardized PT. The primary goal was to establish if there is additional longerterm benefit of continuing CPM after hospital discharge.
Methods: A RCT was conducted with 60 pts with knee OA, who underwent TKA and experienced early
postoperative flexion impairment. Subjects were randomized over 2 groups. Experimental group received
PT intervention + CPM for 2 weeks, at home, for 4 hours daily. Control group received traditional PT only,
for 2 weeks after hospital d/c. Both groups received the same treatment in the hospital, a standardized PT
program consisting of 20 minutes of PT and 4 hours of CPM use daily for 4 days. CPM began POD 0 and
was used for 2 h x 2, daily. Outcome measurements were: functional status, WOMAC and Knee Society
Score (KSS); ROM; perceived effect, 7-point Likert scale; post-op medication use; satisfaction with tx (11point Likert); satisfaction with tx result (11-point Likert); adherence to tx protocols and CPM use; quantity,
duration and nature of PT intervention. Outcome measures were taken at 17 days, 6 weeks, and 3 mos s/p.
Results: Prolonged CPM use slightly improved short-term ROM. Assessment at 6 weeks and 3 mos s/p
found no long-term carry-over. No functional benefits of the increased short-term ROM where reflected in
other outcome measurements.
Critique/Bottom Line: The results of this study indicate that prolonged CPM use has a short-term effect on
ROM; however, this did not translate into long-term improvements in ROM or better functional outcomes.
The results of this study do not support the addition of CPM treatment to conventional PT in the home
setting s/p TKA because CPM provided no benefit in long-term functional recovery or ROM.
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Herbold, J. A. , Bonistall, K. , & Blackburn, M. (2012). Effectiveness of continuous passive motion in an
Inpatinet rehabilitation hospital after total knee replacement: a matched cohort study. American
Academy of Physical Medicine and Rehabilitation, 4, 719-725.
http://dx.doi.org/10.1016/j.pmrj.2012.07.004
Level of Evidence (Oxford Scale): 2b
Purpose: The purpose of this study was to examine the use of CPM as an adjunct to PT after TKA in pts
who were transferred to an inpatient rehabilitation facility (IRF) and to compare the effectiveness of CPM on
AROM, functional tasks, destination after discharge, the need for home care services, and the ambulation
device at discharge.
Methods: A matched cohort retrospective design was used to compare outcomes of pts admitted to IRF
with <75 deg of knee flex, who either did or did not receive CPM. There were 61 matched pairs, who were
analyzed. These pts were selected from a pool of pts who met inclusion and did not meet exclusion criteria
and were admitted to an IRF directly from an acute-care hospital after TKR between 2008 and 2009.
Outcome measures were obtained from the pts’ medical records and included: d/c AROM flex and ext,
AROM gain from admission to d/c, d/c FIM subtotal for motor and cognitive and total score, FIM gain from
admission to d/c, d/c disposition, device used for amb at d/c, and use of home health services after d/c.
Results: No statistically significant differences were found in any of the outcome variables.
Critique/Bottom Line: The results of this study indicate that CPM use in the IRF setting does not improve
knee ROM, FIM scores, d/c disposition, AD use, or home health services use after d/c from IRF. Therefore,
according to this study, the use of CPM in the IRF, with pts with poor initial AROM knee flex, is not justified.
21
Grella, Ryan J. (2008). Continuous passive motion following total knee arthroplasty: a useful adjunct to
Early mobilisation?. Physical Therapy Reviews, 13(4), 269-279. doi: 10.1179/1743288o8X309197
Level of Evidence (Oxford Scale): 1a
Purpose: The purpose of this systematic review was to determine the effectiveness of CPM following TKA
when compared to a rehabilitation protocol that permits early knee mobilization and to determine if an
optimal CPM dosage schedule exists.
Methods: Only RCTs published in English that compared PT plus CPM in the inpatient setting to a control
group who received only PT were included. CINAHL and MEDLINE were searched to find trials
investigating CPM after TKA and key search terms were listed in this study. Participants had to be receiving
a primary TKA, with a pre-operative diagnosis of OA or RA. Both groups had to receive the same PT tx that
initiated CPM and ROM activities of the surgical knee (whether active or passive) by POD2. This did not
include quad sets or SLR. Outcomes of interest were short and long-term knee ROM, function, pain,
complications, LOS in hospital, and quadriceps strength. The quality of studies was assessed by 3
reviewers, and the Cochrane methods of selection were followed. Data were divided into short-term (</=7
days s/p) and long-term (>7 days s/p) effects.
Results: There was strong evidence that CPM exerts no influence on short and long-term knee extension,
long-term knee flex, long-term function, pain, complications, and LOS in hospital. Data for short-term knee
flex, quadriceps strength, and short-term function were conflicting. Preliminary evidence suggests that CPM
applied immediately postoperatively, at a high flexion arc of motion, and for a significant amount of time
each day leads to better outcomes with regards to short-term knee flex.
Critique/Bottom Line: The use of CPM as an adjunct to traditional PT tx in the acute care setting should be
questioned as the current body of research generally does not support its use. However, before
summarizing that CPM is unnecessary, further clinical trials using more aggressive CPM parameters
should be conducted as this may provide better outcomes.
22
Harvey, L.A., Brosseau, L., P& Herbert, R.D. (2014). Continuous passive motion following total knee
arthroplasty in people with arthritis (Review). Cochrane Database of Systematic Reviews 2,
1-121. doi: 10.1002/14651858.CD004260.pub3.
Level of Evidence (Oxford Scale): 1a
Purpose: The focus of this SR was to assess the benefits and harms of CPM and standard postoperative
care versus similar postoperative care, with or without additional knee exercises in people s/p TKA.
Methods: Several databases were searched for RCTs in which the experimental group received CPM, and
both the experimental and control groups received similar postoperative care and therapy following TKA in
people with arthritis. 2 authors independently selected trials for inclusion, extracted data and assessed
bias. Primary outcomes of interest were AROM knee flex, pain, QOL, function, participants’ global
assessment of tx effectiveness, incidence of manipulation under anesthesia and adverse events.
Secondary outcomes were PROM knee flex, AROM knee ext, PROM knee ext, LOS in hospital, swelling
and quadriceps strength.
Results: There was moderate-quality evidence that CPM does not have clinically important short-term
effects on AROM knee flex, medium-term effects on function, and medium-term effects on QOL. Lowquality evidence that CPM does not have clinically important short-term effects on pain or reducing the risk
of adverse events. There was very low-quality evidence to indicate that COM reduces the risk of
manipulation under anesthesia. There was insufficient evidence to determine effect of CPM on tx
effectiveness.
Critique/Bottom Line: CPM does not have a clinically important effect on ROM knee flexion, pain, function
or quality of life, to justify its use. CPM may reduce risk of manipulation under anesthesia and risk of
developing adverse events, but the quality of evidence supporting this is very low and low, respectively.
Therefore, the effect of CPM use is still controversial and more research needs to be done.
23
Brosseau, L., Milne, S., Wells, G., Tugwell, P., Robinson, V., . . . Drouin, H. (2004). Efficacy of continuous
Passive motion following total knee arthroplasty: a metaanalysis. The Journal of Rheumatology 31
(11), 2251-2264. doi:
Level of Evidence (Oxford Scale): 1a
Purpose: The focus of this meta-analysis was to examine the effectiveness of CPM following TKA; CPM
was compared to standard PT tx s/p TKA
Methods: Cochrane methods were used to locate studies, and 2 independent reviewers examined the
articles and assessed them for inclusion and relevance. Both groups, experimental and control, received
standard PT tx, as defined by this analysis, consisting of any combination of the following interventions:
ROM, muscle strengthening, functional exercises, gt training, immobilization, and ice. The experimental
group also received CPM. All comparative controlled trials, including RCT, controlled clinical trials without
randomization, case-control, and cohort studies were included. Outcome measurements included: AROM
and PROM of knee, length of hospital stay, pain, swelling, fixed flexion deformity, and quadriceps strength
at the end of treatment and during follow-up.
Results: This review found significant improvements in AROM knee flexion and analgesic use 2 weeks
postoperatively with the use of COM and PT compared to PT alone. Also LOS in hospital and need for
knee manipulations were significantly decreased in CPM group. Not enough data were available to
compare the degree of knee flexion applied or number of hours of application of CPM. However, no other
outcome found significant effectiveness for CPM use.
Critique/Bottom Line: The results from this meta-analysis suggest that CPM combined with PT interventions
is effective at increasing active knee flexion 2 weeks post TKA relative to PT intervention alone. However,
the clinical significance of an additional 4 degrees of knee flexion can be questioned. Also, CPM does not
result in additional ROM over the long-term, 1-2 years s/p. This meta-analysis takes the stance that as long
as the benefits of CPM outweigh the cost, CPM should be considered a viable tx option.
24
Table 1. Table of Articles
#
Study
Oxford
Pedro
Level of Score
Evidence
1b
7/10
Purpose
Outcome
Measures
1
Herbold,
J. A. , et
al. (2014)
To determine
the effects of
using a CPM
device for pts
with poor ROM
s/p TKA, who
were admitted
for post-acute
rehabilitation.
Knee AROM,
TUG score,
knee girth,
total FIM
scores,
ambulation
device at d/c,
LOS, and
self-reported
WOMAC
scores
2
Boese, C.
K., et al.
(2014)
2b
5/10
BruunOlsen, V.
, et al.
(2009)
1b
8/10
To evaluate
the effects of
early
aggressive
CPM and fixed
flexion
proceeding to
progressive
CPM on shortterm outcomes
compared to
standardized
PT alone.
To examine
whether CPM
as an adjunct
to active
exercises had
any short-term
3
Results
Answer
to Clinical
Question
Yes
All subjects, in
both the CPM
and non-CPM
groups,
significantly
improved from
admission to
the IRF to d/c
in all outcome
measurements.
However, there
was no
statistically
significant
differences in
any of the d/c
outcome
measures of
the CPM group
compared to
the non-CPM
group.
Change in
There were no Yes
hemoglobin
significant
from pre-op to differences
POD 1 and 2, between the
self-reported groups for any
pain scores
of the outcome
on VAS, knee variables.
girth, hospital
LOS, and
AROM and
PROM knee
flex and ext
Pain on VAS,
TUG timed 40
m walking,
timed stair
climbing,
ROM.
There were no
statistically
significant
differences
between the
groups for any
Yes
25
4
Denis, M.
, et al.
(2006)
1b
8/10
5
Maniar,
R. N. , et
al. (2012)
1b
7/10
6
Lenssen,
T. , et al.
(2008)
1b
8/10
effects (after 1
week and 3
months) on
pain, ROM,
timed walking
and stair
climbing.
To compare
the
effectiveness
of 3 in-hospital
rehabilitation
programs with
and without
CPM for knee
flexion and
extension
ROM,
functional
ability, and
LOS, after
primary TKA.
To evaluate in
a prospective,
randomized
manner the
effect of CPM
in the hospital
setting,
compared to
traditional PT
only, by
assessing
specific
parameters.
To investigate
the
effectiveness
of prolonged
CPM use in
the home
situation as an
adjunct to
standardized
PT. The
primary goal
of the outcome
variables at 1
week or 3
months.
AROM knee
flexion and
extension,
TUG,
WOMAC, and
LOS
There were no
statistically
significant
differences
between the
groups for any
of the outcome
measures at
discharge.
Yes
Pain of VAS,
AROM of
knee, TUG
values,
suprapatellar
and calf
girths,
WOMAC and
SF-12 scores,
and wound
healing.
There were no
statistically
significant
differences
between the
groups for any
of the outcome
measurements
pre-operatively
and s/p on
days 3, 5, 14,
42, and 90.
Yes
Functional
status,
WOMAC and
Knee Society
Score (KSS);
ROM;
perceived
effect, 7-point
Likert scale;
post-op
medication
Prolonged
Yes.
CPM use
slightly
improved shortterm ROM.
Assessment at
6 weeks and 3
mos s/p found
no long-term
carry-over. No
functional
26
was to
establish if
there is
additional
longer-term
benefit of
continuing
CPM after
hospital d/c.
7
Herbold,
J. A., et al
(2012)
2b
8
Grella, R.
J. (2008)
1a
To examine
the use of
CPM as an
adjunct to PT
after TKA in
pts who were
transferred to
an inpatient
rehabilitation
facility (IRF)
and to
compare the
effectiveness
of CPM on
AROM,
functional
tasks,
destination
after d/c, the
need for home
care services,
and the
ambulation
device at d/c.
To determine
the
effectiveness
of CPM
following TKA
when
compared to a
use;
satisfaction
with tx (11point Likert);
satisfaction
with tx result
(11-point
Likert);
adherence to
tx protocols
and CPM use;
quantity,
duration and
nature of PT
intervention
d/c AROM
flex and ext,
AROM gain
from
admission to
d/c, d/c FIM
subtotal for
motor and
cognitive and
total score,
FIM gain from
admission to
d/c, d/c
disposition,
device used
for amb at
d/c, and use
of home
health
services after
d/c.
benefits of the
increased
short-term
RPM were
reflected in
other outcome
measurements.
No statistically
significant
differences
were found in
any of the
outcome
variables.
Yes
Short and
long-term
knee ROM,
function, pain,
complications,
LOS in
hospital, and
There was
strong
evidence that
CPM exerts no
influence on
short and longterm knee
Yes
27
9
Harvey,
L.A., et al
(2014)
La
rehabilitation
protocol that
permits early
knee
mobilization to
determine if an
optimal CPM
dosage
schedule
exists.
quadriceps
strength.
To assess the
benefits and
harms of CPM
and standard
postoperative
care versus
similar
postoperative
care, with or
without
additional knee
exercises in
people s/p
TKA.
Primary
outcomes:
AROM knee
flex, pain
QOL,
function,
participants’
global
assessment
of tx
effectiveness,
incidence of
manipulation
under
anesthesia
extension,
long-term knee
flex, long-term
function, pain,
complications,
and LOS in
hospital. Data
for short-term
knee flex,
quadriceps
strength, and
short-term
function were
conflicting.
Preliminary
evidence
suggests that
CPM applied
immediately
postoperatively,
at a high flexion
arc of motion,
and for a
significant
amount of time
each day leads
to better
outcomes with
regards to
short-term knee
flex.
There was
Yes
moderatequality
evidence that
CPM does not
have clinically
important shortterm effects on
AROM knee
flex, mediumterm effects on
function, and
medium-term
effects on QOL.
Low-quality
28
and adverse
events.
Secondary
outcomes:
PROM knee
flex, AROM
knee ext,
PROM knee
ext, LOS in
hospital,
swelling and
quadriceps
strength.
10
Brosseau, 1a
L. , et al.
(2004)
evidence that
CPM does not
have clinically
important shortterm effects on
pain or
reducing the
risk of adverse
events. There
was very lowquality
evidence to
indicate that
CPM reduces
the risk of
manipulation
under
anesthesia.
There was
insufficient
evidence to
determine
effect of CPM
on tx
effectiveness.
The focus of
AROM and
This review
Yes
this metaPROM of
found
analysis was to knee, length
significant
examine the
of hospital
improvements
effectiveness
stay, pain,
in AROM knee
of CPM
swelling, fixed flexion and
following TKA; flexion
analgesic use 2
CPM was
deformity, and weeks
compared to
quadriceps
postoperatively
standard PT tx strength at
with the use of
s/p TKA.
the end of tx
CPM and PT
and during
compared to
follow-up.
PT alone. Also,
LOS in hospital
and need for
knee
manipulations
were
significantly
decreased in
CPM group.
29
Not enough
data were
available to
compare the
degree of knee
flexion applied
or number of
hours of
application of
CPM. However,
no other
outcome found
significant
effectiveness
for CPM use.
Discussion:
When CPM was used as an adjunct to traditional PT tx s/p TKA, 6 studies found no statistically
significant difference in outcome measurements such as: knee ROM, knee girth, TUG score, FIM scores,
ambulation device at d/c, LOS, pain, SF-12 scores, and WOMAC scores.
One study by Lenssen et al. (2008), showed that prolonged CPM use slightly improved short-term
ROM. However, there was no long-term carryover and no functional benefits of this improved short-term
ROM were reflected in other outcome measures: functional status, WOMAC, Knee Society Score,
perceived effect (7 point Likert scale), and satisfaction with tx (11-poitn Likert). This study looked at CPM tx
in the home, after hospital d/c.
Another study by Grella et al. (2008) found that CPM applied immediately s/p TKA at a high flexion
arc of motion and for a significant amount of time leads to better outcomes with regards to short-term knee
flexion ROM. However, there was strong evidence to suggest that COM exerted no influence on long-term
knee flexion, short and long-term knee extension, long-term function, pain complications, and LOS in
hospital. Therefore, this gain in short term knee flexion ROM did not show long-term carryover, nor did it
improve pt’s function in the short or long-term.
30
The review by Harvey et al. (2014) found moderate-quality evidence that CPM does not have
clinically important short-term effects on AROM knee flexion, medium-term effects on function, and
medium-term effects on QOL. Low-quality evidence that CPM does not have clinically important short-term
effects on pain or reducing the risk of adverse events, and very low-quality evidence to indicate that CPM
reduces the risk of manipulation under anesthesia. Therefore, this study concluded that there was
insufficient evidence to determine the effect of CPM on tx effectiveness.
Lastly, the review by Brosseau et al. (2004) found significant improvement in AROM knee flexion
and analgesic use 2 weeks postoperatively with the use of CPM as an adjunct to PT tx compared to PT tx
alone. Also, this study found a significant reduction in LOS in hospital and need for knee manipulations in
COM group. However, no other outcomes were found to be statistically significant for the effectiveness of
CPM use.
Upon completion of the literature review, the treatment interventions for Patient A would have been
modified. Patient A would have still received traditional PT tx, but she would not have received CPM tx. The
general consensus of the literature pertaining to CPM use as an adjunct to PT, is that it does not improve
functional outcomes. CPM use may improve short-term knee flexion ROM; however, this does not show
any carryover and is not reflected in other outcome measures. Therefore, there is no benefit of CPM use
according to the literature. Although, many studies did state that the results were inconclusive and more
research needs to be done on specific CPM protocols, time-frames, and use with a more specified subset
of pts s/p TKA.
Conclusion/Bottom Line:
The PICO question was: In patients who have undergone TKA does PT intervention plus CPM use
vs PT intervention alone cause greater improvements in outcome measurements (ROM, pain, LOS, AD
use, functional status)? In terms of answering this, the conclusion from this literature appraisal and review
is that CPM use as an adjunct to PT intervention does not lead to greater improvements in outcome
31
measurements, than PT intervention alone. The majority of the studies that were reviewed showed no
statistically significant differences in outcome measures between CPM group and non-CPM group s/p TKA.
A few studies showed improvements in short-term knee flexion ROM, when CPM was applied immediately
after surgery. However, these studies showed that this improvement in short-term knee flexion ROM did not
carryover and was not reflected in other outcome measurements. Therefore, CPM use as part of the
therapy protocol s/p TKA should be reconsidered.
32
References:
1. Boese, C. K., Weis, M., Phillips, T., Lawton-Peters, S., Gallo, T., & Centeno, L. (2014). The efficacy of
Continuous passive motion after total knee arthroplasty: a comparison of three protocols.
The Journal of Arthroplasty, 29, 1158-1162. http://dx.doi.org/10.1016/j.arth.2013.12.005
2. Brosseau, L., Milne, S., Wells, G., Tugwell, P., Robinson, V., . . . Drouin, H. (2004). Efficacy of
continuous passive motion following total knee arthroplasty: a metaanalysis. The Journal of
Rheumatology 31 (11), 2251-2264. Retrieved from
http://www.jrheum.org.libproxy.unm.edu/content/31/11/2251.long
3. Bruun-Olsen, V., Heiberg, K. E., & Mengshoel, A. M. (2009). Continuous passive motion as an adjunct to
active exercises in early rehabilitation following total knee arthroplasty-a randomized controlled
trial. Disability and Rehabilitation 31 (4), 277-283. doi: 10.1080/09638280801931204
4. Denis, M. , Helene, M. , Caron, F. , Ouellet, D., Paquet, J., & Nolet, L. (2006). Effectiveness of
continuous passive motion and conventional physical therapy after total knee arthroplasty: a
randomized clinical trial. Physical Therapy, 86 (2), 175-185.
http://ptjournal.apta.org/content/86/2/174.long
5. Grella, Ryan J. (2008). Continuous passive motion following total knee arthroplasty: a useful adjunct to
Early mobilisation?. Physical Therapy Reviews, 13(4), 269-279. doi: 10.1179/1743288o8X309197
6. Harvey, L.A., Brosseau, L., P& Herbert, R.D. (2014). Continuous passive motion following total knee
arthroplasty in people with arthritis (Review). Cochrane Database of Systematic Reviews 2,
1-121. doi: 10.1002/14651858.CD004260.pub3.
33
7. Herbold, J. A. , Bonistall, K. , & Blackburn, M. (2012). Effectiveness of continuous passive motion in an
Inpatinet rehabilitation hospital after total knee replacement: a matched cohort study. American
Academy of Physical Medicine and Rehabilitation, 4, 719-725.
http://dx.doi.org/10.1016/j.pmrj.2012.07.004
8. Herbold, J. A., Bonistall, K., Blackburn, M., Agolli, J., Gaston, S., Gross, C., …Babyar, S. (2014).
Randomized controlled trial of the effectiveness of continuous passive motion after total
knee replacement. Archives of Physical Medicine and Rehabilitation, 95, 1240-5. doi:
http://dx.doi.org/10.1016/j.apmr.2014.03.012
9. Lenssen, T. , Van Steyn, M. , Crijns, Y. , Waltje, E. , Roox, G. M. , Geesink, R. , . . . De Bie, R. (2008).
Effectiveness of prolonged use of continuous passive motion (CPM), as an adjunct to
Physiotherapy, after total knee arthroplasty. BMC Musculoskeletal Disorders, 9 (60), 1471-1274.
doi: 10.1186/1471-2474-9-60
10. Maniar, R. N., Baviskar, J. V., Singhi, T., & Rathi, S. S. (2012). To use or not to use continuous passive
Motion post-total knee arthroplasty. The Journal of Arthroplasty 27 (2), 193-201. doi:
10.1016/j.arth.2011.04.009
34
Appendices:
Intervention – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Boese, C. K., Weis, M., Phillips, T., Lawton-Peters, S., Gallo, T., & Centeno, L. (2014). The efficacy of
Continuous passive motion after total knee arthroplasty: a comparison of three protocols.
The Journal of Arthroplasty, 29, 1158-1162. http://dx.doi.org/10.1016/j.arth.2013.12.005
Level of Evidence (Oxford scale): 2b
Is the purpose and background information sufficient?
Appraisal Criterion
Reader’s Comments
Study Purpose
Yes, the purpose of this study is stated clearly. The
Stated clearly?
aim of this investigation was to evaluate the
Usually stated briefly in abstract and in greater
effects of early aggressive CPM and fixed flexion
detail in introduction. May be phrased as a
proceeding progressive CPM on short-term
question or hypothesis.
outcomes compared to standardized physical
A clear statement helps you determine if topic is
therapy alone.
important, relevant and of interest to you. Consider
how the study can be applied to PT and/or your
own situation. What is the purpose of this study?
Literature
CPM use has rapidly grown to augment pt’s rehab
Relevant background presented?
following TKA. The reported benefits of CPM use
A review of the literature should provide
include increased improvements in ROM,
background for the study by synthesizing relevant decreased pain and swelling, reduced need for
information such as previous research and gaps in manipulation under anesthesia decreased hospital
current knowledge, along with the clinical
length of stay and reduction in overall cost.
importance of the topic.
However, this the literature for the benefits of CPM
Describe the justification of the need for this study has not been conclusive. Also, research currently
suggests there are no long term benefits of CPM
use and no differences in outcomes between pts
who use a CPM and those who do not. Also,
current literature may be difficult to generalize and
apply to practice because different CPM protocols
have been used.
Does the research design have strong internal validity?
Appraisal Criterion
Reader’s Comments
Patients were randomly assigned by consecutive
 Discuss possible threats to internal
sequencing into one of three protocol groups, A,
validity in the research design. Include: B, C, during pre-operative classes. The nature of
 Assignment
35
Attrition
History
Instrumentation
Maturation
Testing
Compensatory Equalization of
treatments
 Compensatory rivalry
 Statistical Regression






Are the results of this therapeutic trial valid?
Appraisal Criterion
1. Did the investigators randomly assign
subjects to treatment groups?
a. If no, describe what was done
b. What are the potential
consequences of this
assignment process for the
study’s results?
2. Did the investigators know who was
being assigned to which group prior to
the allocation?
a. If they were not blind, what are
the potential consequences of
this knowledge for the study’s
results?
3. Were the groups similar at the start of
the trial? Did they report the
demographics of the study groups?
a. If they were not similar – what
differences existed?
b. Do you consider these
differences a threat to the
research validity? How might
the differences between groups
affect the results of the study?
4. Did the subjects know to which
treatment group they were assign?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
CPM prevented blinding in this study. Patients
were actively recruited from December 2007 to
May 2010. Consent was obtained from 218
patients. Of these, there were 10 surgery
cancellations, 6 patients who met the exclusion
criteria, and 42 patients removed due to staff
errors, missing
data, requests to withdraw from the study, and
poor health for participation. Total 160 patients
completed the study.
Reader’s Comments
Yes, patients were randomly assigned by
consecutive sequencing into one of three protocol
groups, A, B, C, during pre-operative classes.
Yes, the nature of CPM prevented blinding in this
study. However, the operating surgeon was blind
to the groups prior to the operation. This could
skew the results of the study by introducing tester
bias.
Yes, the groups were similar in at the start of the
trial. Demographics are reported in a table that is
included in the study.
Yes, the subjects knew to which treatment group
they were assigned. Blinding is difficult to
accomplish due to the nature of the CPM machine.
This could have biased the results of the study or
introduced compensatory rivalry and threatened
internal validity.
36
5. Did the investigators know to which
treatment group subjects were
assigned?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
6. Were the groups managed equally,
apart from the actual experimental
treatment?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
7. Was the subject follow-up time
sufficiently long to answer the
question(s) posed by the research?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
8. Did all the subjects originally enrolled
complete the study?
a. If not how many subjects were
lost?
b. What, if anything, did the
authors do about this attrition?
c. What are the implications of the
attrition and the way it was
Yes, the investigators knew to which treatment
group the subjects were assigned. Blinding is
difficult to accomplish due to the nature of the
CPM machine. This could have introduced bias
and threatened internal validity.
With the exception of the CPM protocol used,
patients received the same care during their
hospital stay. Physical therapy targeted active
motion of the knee and functional mobility.
Patients were encouraged to ambulate on the
morning of the first post-operative day. Twice daily
therapy protocol included quad sets, short arc
quads, long arc
quads, hip abduction, straight leg raises, ankle
pumps and gluteal sets beginning on the first
postoperative day. Patients were encouraged to
rock in a rocking chair four times a day for 20
minutes to reduce joint stiffness. A five pound
sand bag was placed on the operative knee
(Ottoman stretch) four times a day for 10 minutes
to promote knee extension as tolerated.
Yes, the follow-up time was 2 days, so outcome
measures were reported for all patients through
post-operative day 2. The aim of this investigation
was to evaluate the effects of early aggressive
CPM and fixed flexion proceeding progressive
CPM on short-term outcomes compared to
standardized physical therapy alone. Therefore,
since this study is looking at early, aggressive
CPM use and short-term outcomes in the acute
care setting; the follow-up time was sufficiently
long enough to answer the question posed by the
researcher.
No, consent was obtained from 218 patients. Of
these, there were 10 surgery cancellations, 6
patients who met the exclusion criteria, and 42
patients removed due to staff errors, missing data,
requests to withdraw from the study, and poor
health for participation. Total 160 patients
completed the study. The authors did not state
how the attrition was handled. Therefore, this
37
handled with respect to the
study’s findings?
9. Were all patients analyzed in the groups
to which they were randomized (i.e. was
there an intention to treat analysis)?
a. If not, what did the authors do
with the data from these
subjects?
b. If the data were excluded, what
are the potential consequences
for this study’s results?
Are the valid results of this RCT important?
Appraisal Criterion
10. What were the statistical findings of this
study?
a. When appropriate use the
calculation forms below to
determine these values
b. Include: tests of differences
With p-values and CI
c. Include effect size with p-values
and CI
d. Include ARR/ABI and RRR/RBI
with p-values and CI
e. Include NNT and CI
f. Other stats should be included
here
11. What is the meaning of these statistical
findings for your patient/client’s case?
What does this mean to your practice?
could skew the data and decrease the internal
validity of this study.
Yes, all patients were analyzed in the groups to
which they were randomized.
Reader’s Comments
Data were analyzed using a MANOVA test for
outcomes on each post-operative day and at final
follow-up; individual ANOVA tests were used as
needed. There were no significant MANOVA test
differences between the groups for any variable.
Drop in Hgb from pre-operative to post-operative
day two was lowest in Group B (goal of 90
degrees stationary CPM on the first post-operative
night), although this difference was not statistically
Significant. During post-operative day two, Group
A patients did show a larger change in leg girth 10
cm below the joint line (P b .01). The overall
MANOVA test for length of stay was close to
significance at
0.09. As the other four factors all had p-values
ranging from 0.94–0.96, the researchers conclude
that the most significant difference between
groups comes from the length of stay factor. The
raw values for length of stay (2.7, 3.2, and 2.6)
days for Groups A, B, and C, respectfully) show a
clinically significant difference. The ANOVA test
for length of stay showed a significantly longer
stay for patients who received the stationary CPM
(Group B) on the first night than for any other
group (P b .01).
Therefore, these statics say that CPM use does
not improve short-term outcomes within the first
two days post-op. However, CPM use may
actually increase length of stay if applied at a fixed
90 degree angle. There was no difference in
moving CPM use vs. no CPM use. Therefore,
CPM use does not improve outcomes and just
increases costs according to this study, so I would
38
not recommend using a CPM in the acute care
setting for my patient.
MCID was not discussed, but the findings were not
statistically significant.
12. Do these findings exceed a minimally
important difference? Was this brought
up or discussed?
a. If the MCID was not met, will you
still use this evidence?
Can you apply this valid, important evidence about an intervention in caring for your
patient/client? What is the external validity?
Appraisal Criterion
Reader’s Comments
13. Does this intervention sound
Research on CPM use is still inconclusive. While
appropriate for use (available,
some studies show it to be a beneficial adjunct to
affordable) in your clinical setting? Do
PT treatment, others show that it does not improve
rd
you have the facilities, skill set, time, 3
function. However, the risks associated with CPM
party coverage to provide this
use are low. The cost of CPM use was discussed
treatment?
in this article. With the verdict being that this
particular facility could save $22, 200 per year if
they discontinued CPM use. With the current state
of healthcare and lack of funding for hospitals,
discontinuing CPM use may be the best course of
action.
14. Are the study subjects similar to your
Yes, the subjects are similar to my patient. My
patient/ client?
patient falls within the age group of 18-90 set by
a. If not, how different? Can you
this study and underwent a single joint TKA,
use this intervention in spite of
followed by a 2 day stay in the acute care setting.
the differences?
15. Do the potential benefits outweigh the
Reported benefits of CPM include facilitated
potential risks using this intervention
improvements in range of motion, decreased pain
with your patient/client?
and swelling, reduced need for manipulation under
Anesthesia, decreased hospital length of stay and
a reduction in overall cost. However, these
benefits remain controversial as the literature on
CPM has not conclusively confirmed these results
since the initial trials by Salter and colleagues. For
instance, research suggests there are no longterm advantages associated with CPM use, while
other studies present no clinical differences
between patients given a CPM versus patients
who complete standard physical therapy alone.
Therefore, previous studies cite benefits, and
since there is no real risk in using a CPM machine
and recent literature has reported inconclusive
results, the potential benefits do outweigh the
potential risks in this situation.
39
16. Does the intervention fit within your
patient/client’s stated values or
expectations?
a. If not, what will you do now?
My patient’s stated values are to improve knee
ROM and function. Therefore, this intervention fits
within that goal.
17. Are there any threats to external validity No, the subjects are generalizable to the
in this study?
population of pts who undergo TKA. There was no
pre-testing, selection bias, or multiple treatment
interference.
What is the bottom line?
Appraisal Criterion
PEDRO score (see scoring at end of form)
Summarize your findings and relate this back
to clinical significance
Reader’s Comments
5/10
CPM provided no apparent benefit to patients
recovering from TKA in all outcome variables. No
clinically significant differences were found in
ROM, swelling, blood loss, pain scores, or active
ROM achieved between any of the groups at any
time. Groups were:
Group A – patients receiving a moving CPM
immediately upon arrival to the orthopedic floor
moving from 0–110 degree range of motion.
Degrees of flexion were adjusted per patient
tolerance. CPM continued daily for a minimum of 5
hours per day as tolerated for a minimum of two
days and was continued until 90 degrees of active
flexion was obtained.
Group B – patients receiving a non-moving CPM
immediately upon arrival to the orthopedic floor.
The operative leg was placed in a fixed, bent
position following surgery and held in this position
during the first night for a minimum of 8 hours and
a maximum of 19 hours. The goal was to hold the
knee stationary at 90 degrees; however, flexion
was decreased as needed for patient comfort.
During all subsequent hospital days, the Group A
protocol was followed.
Group C – patients who did not receive a CPM
machine during their hospital stay. The operative
leg rested on the hospital bed and the patient was
repositioned for comfort by nursing staff.
Therefore, this study did not find any benefit to
using CPM in the acute care setting with pts who
have undergone TKA. This study also proclaimed
that discontinuing CPM use in the acute care
40
setting would be an excellent way to decrease
hospital costs, which could transfer into improved
patient care.
41
Systematic Review – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Brosseau, L., Milne, S., Wells, G., Tugwell, P., Robinson, V., . . . Drouin, H. (2004). Efficacy of continuous
Passive motion following total knee arthroplasty: a metaanalysis. The Journal of Rheumatology 31
(11), 2251-2264. Retrieved from http://www.jrheum.org.libproxy.unm.edu/content/31/11/2251.long
Level of Evidence (Oxford scale): 1a
Does the design follow the Cochrane method?
Appraisal Criterion
Step 1 – formulating the question
• Do the authors identify the focus of the
review
• A clearly defined question should
specify the types of:
• people (participants),
• interventions or exposures,
• outcomes that are of interest
• studies that are relevant to
answering the question
Reader’s Comments
The objective of this meta-analysis is to examine
the effectiveness of continuous passive motion
(CPM) following total knee arthroplasty (TKA).
CPM is compared to standard PT treatments
conducted on patients after a total TKA. Standard
PT treatment, as defined by this analysis, consists
of any combination of the following interventions:
ROM exercises (ROM), muscle strengthening
exercises (isometric, dynamic), functional
exercises, gait training, immobilization, and ice.
The outcome measures of interest for this metaanalysis were active and passive knee ROM,
length of hospital stay, pain, swelling, fixed flexion
deformity, and quadriceps strength at end of
treatment and during follow-up.
Step 2 – locating studies
The literature was search up to and including
December 2003 according to the search strategy
 Should identify ALL relevant literature
outlined by the Cochrane Collaboration for RCTs.
 Did they include multiple databases?
Medline, Embase, Healthstar, Sports Discus,
 Was the search strategy defined and
CINAHL, the Cochrane Controlled Trials Register,
include:
the PEDro database, the specialized registry of
o Bibliographic databases used
the Cochrane musculoskeletal group, and the
as well as hand searching
Cochrane field of physical and related therapies
o Terms (key words and index
were searched using a keyword and text word
terms)
search strategy. Reference lists of the included
o Citation searching: reference
trials were also searched and content experts
lists
o Contact with ‘experts’ to identify were contacted for additional studies.
‘grey’ literature (body of
materials that cannot be found
easily through conventional
channels such as publishers)
o Sources for ‘grey literature’
42
Part 3:Critical Appraisal/Criteria for Inclusion
• Were criteria for selection specified?
• Did more than one author
assess the relevance of each
report
• Were decisions concerning
relevance described; completed
by non-experts, or both?
• Did the people assessing the
relevance of studies know the
names of the authors,
institutions, journal of
publication and results when
they apply the inclusion
criteria? Or is it blind?
Part 3 – Critically appraise for bias:
• Selection –
• Were the groups in the study
selected differently?
• Random? Concealed?
• Performance• Did the groups in the study
receive different treatment?
• Was there blinding?
• Attrition –
• Were the groups similar at the
end of the study?
• Account for drop outs?
• Detection –
• Did the study selectively report
the results?
• Is there missing data?
Part 4 – Collection of the data
 Was a collection data form used and is
it included?
 Are the studies coded and is the data
coding easy to follow?
Two independent reviewers examined the titles
and abstracts of the articles identified by the
search and selected trials that met the inclusion
criteria. Every article that was classified as
relevant by at least one review were retrieved.
These articles were then reexamined to make sure
they met the inclusion criteria. Only trials meeting
this inclusion criteria were selected: subjects were
18 years or older and had a pre-surgery diagnosis
of degenerative joint disease, intervention and
control groups of 5 or more individuals each, and
measuring rehabilitative outcomes. Both groups,
experimental and control, received PT. The
experimental group also received CPM. All
comparative controlled trials, including RCT,
controlled clinical trials without randomization,
case-control, and cohort studies were included.
Acceptable interventions included any form of
fitness exercise. Placebo, untreated, or active
interventions were all acceptable control groups.
The control group in the studies were given PT
alone and the experimental groups received PT
plus CPM. However, 5 studies provided identical
PT treatment to the experimental and control
groups, while 4 studies were found to have
provided one group additional PT. The CPM
protocols and the PT protocols differed from study
to study. Therefore, this could have influenced the
combined results of the study. Protocols differed
among trials, and in some studies, the treatment
parameters were not reported in sufficient detail.
Some of the RCTs included were single blind.
However, many of them were not blinded, due to
the nature of CPM treatment. Eight articles
provided detailed information of withdrawals and
drop outs. 3 failed to provide a description of drop
outs. Heterogeneity of results was a problem for
several outcomes. ROM measurements were not
specifies as being active or passive.
The results of the individual trials were extracted
from the studies using predetermined extraction
forms by 2 independent reviewers, and data was
cross-checked by a third reviewer. The extraction
forms were developed and pilot-tested based on
other forms used by the Cochrane
musculoskeletal review group.
43

Were studies identified that were
excluded & did they give reasons why
(i.e., which criteria they failed).
Are the results of this SR valid?
Appraisal Criterion
18. Is this a SR of randomized trials? Did
they limit this to high quality studies at
the top of the hierarchies
a. If not, what types of studies
were included?
b. What are the potential
consequences of including
these studies for this review’s
results?
19. Did this study follow the Cochrane
methods selection process and did it
identify all relevant trials?
a. If not, what are the
consequences for this review’s
results?
20. Do the methods describe the processes
and tools used to assess the quality of
individual studies?
a. If not, what are the
consequences for this review’s
results?
21. What was the quality of the individual
studies included? Were the results
consistent from study to study? Did the
investigators provide details about the
research validity or quality of the studies
included in review?
22. Did the investigators address
publication bias
Are the valid results of this SR important?
Studies were excluded for several reasons
including: no clinical outcomes of interest; no
variance reported on outcomes. A table was
included in this meta-analysis listing the excluded
trials and specific reasons for exclusion.
Reader’s Comments
Yes, this is an SR of RCTs. The methodological
quality of the studies was calculated and the
median methodological quality was 2 out of a
maximum of 5 points, and the quality scores
ranged from 1-3. Of the 14 RCTs, 3 scored full
points for randomization, none were double
blinded, and 3 failed to provide a description of
dropouts. Therefore, the quality of these studies
was good, but it could have been better.
Therefore, this could bias the results of the SR.
Yes, the study followed the Cochrane methods
selection process and identified all relevant trials.
Yes, the quality of each study was assessed by 2
independent reviewers, and quality assessment
examined the extent to which the RCT design,
data collection, and statistical analysis minimized
or avoided biases in its treatment comparisons.
The Jadad scale was used to perform the quality
assessment. Differences in scoring were resolved
by consensus, and a third reviewer was consulted
when necessary.
Yes, the quality of the individual studies was
included, and the investigators provided details
about the quality of the studies included in the
review. The results for CPM use and its effect on
increased knee flexion, decreased hospital stay,
and decreased need for manipulation were
consist from study to study.
Due to the limited number of studies included in
this meta-analysis, publication bias may have
occurred because there were few studies that fit
the inclusion criteria.
44
Appraisal Criterion
23. Were the results homogenous from study
to study?
a. If not, what are the
consequences for this review’s
results?
Reader’s Comments
Confidence intervals from various studies
overlapped on forest plots regarding the effect of
CPM on post-op manipulation, passive knee
extension, and passive knee flexion indicating
homogenous results.
24. If the paper is a meta-analysis did they
Yes, they reported the statistical results and
report the statistical results? Did they
included a forest plot with CIs.
include a forest plat? What other
statistics do they include? Are there
CIs?
25. From the findings, is it apparent what
Yes, CIs and forest plots are included in this metathe cumulative weight of the evidence
analysis, so therefore the cumulative weight of the
is?
evidence is apparent.
Can you apply this valid, important evidence from this SR in caring for your patient/client? What
is the external validity?
Appraisal Criterion
Reader’s Comments
26. Is your patient different from those in
No, my patient is similar to those included in this
this SR?
SR because she was over 18 years old, had a presurgery diagnosis of OA, and was hospitalized
following a TKA.
27. Is the treatment feasible in your
Yes, this treatment is feasible in the acute care
setting? Do you have the facilities, skill setting.
set, time, 3rd party coverage to provide
this treatment?
28. Does the intervention fit within your
Yes, this intervention fits within my patient’s stated
patient/client’s stated values or
values of increasing knee ROM and improving
expectations?
functional outcomes.
a. If not, what will you do now?
What is the bottom line?
Appraisal Criterion
Summarize your findings and relate this back
to clinical significance
Reader’s Comments
The results from this meta-analysis suggest that
CPM combined with PT interventions is effective at
increasing active knee flexion 2 weeks post TKA
relative to PT intervention alone. However, the
clinical significance of an additional 4 degree of
knee flexion can be questioned. However, CPM
does not result in additional range over the long
term, one or 2 years post-surgery. Statistically
significant results were found for the outcome of
length of hospital stay. The patients who receive
CPM in addition to PT are discharged home from
the hospital earlier than those who receive PT
45
treatment alone. CPM in addition to PT also
reduced the number of postoperative knee
manipulations required relative to PT alone. No
statistically significant difference was found for the
outcome of active or passive knee extension.
Results on the outcome of pain are limited
because it has been suggested that rhythmic joint
movement inhibits the pain spasm reflex. However,
these results were not supported by the limited
data in this meta-analysis. This meta-analysis
takes the stance that as long as the benefits of
CPM outweigh the cost, CPM should be
considered a viable treatment option. CPM
combined with conventional PT may be utilized to
produce small increases in active knee flexion
ROM, to decrease length of hospital stay, and to
reduce the risk of manipulation following TKA.
These benefits will need to be weighted against
the inconvenience and cost of CPM. Further
studies need to be done to reassess the
effectiveness of CPM by altering treatment
variables. Therefore, because CPM use combined
with PT was shown to improve outcomes in this
meta-analysis, CPM use would be indicated for
use in the acute care setting.
46
Intervention – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Bruun-Olsen, V., Heiberg, K. E., & Mengshoel, A. M. (2009). Continuous passive motion as an adjunct to
active exercises in early rehabilitation following total knee arthroplasty-a randomized controlled
trial. Disability and Rehabilitation 31 (4), 277-283. doi: 10.1080/09638280801931204
Level of Evidence (Oxford scale): 1b
Is the purpose and background information sufficient?
Appraisal Criterion
Reader’s Comments
Study Purpose
Continuous passive motion is frequently used postStated clearly?
operatively to increase knee range of motion after
Usually stated briefly in abstract and in greater
total knee arthroplasty in spite of little conclusive
detail in introduction. May be phrased as a
evidence. The aim of this study was to examine
question or hypothesis.
whether continuous passive motion (CPM) as an
A clear statement helps you determine if topic is
adjunct to active exercises had any short time
important, relevant and of interest to you. Consider effects (after one week and three months) on pain,
how the study can be applied to PT and/or your
range of motion, timed walking and stair climbing.
own situation. What is the purpose of this study?
Yes, the article cites literature which states that the
Literature
benefit of using CPM after TKA is conflicting. The
Relevant background presented?
use of CPM is costly and time-consuming, and this
A review of the literature should provide
study states subjective data that CPM use
background for the study by synthesizing relevant increases pain in some patients. Therefore, the
information such as previous research and gaps in benefits of CPM use need to be examined.
current knowledge, along with the clinical
importance of the topic.
Describe the justification of the need for this study
Does the research design have strong internal validity?
Appraisal Criterion
Reader’s Comments
Patients were randomly assigned to groups. 4
 Discuss possible threats to internal
patients did not complete outcome measurement
validity in the research design. Include: at 3 months, but the authors did not include their
 Assignment
data in the results. Instrumentation could pose a
 Attrition
threat to research design, as ROM was measured
 History
using a goniometer and inter-rater reliability can
 Instrumentation
vary. Also, knee circumference measurements
 Maturation
have poor intra-rater and inter-rater reliability.
 Testing
However, goniometry was standardized, practiced,
and discrepancies were discussed and measured
47
 Compensatory Equalization of
treatments
 Compensatory rivalry
 Statistical Regression
Are the results of this therapeutic trial valid?
Appraisal Criterion
29. Did the investigators randomly assign
subjects to treatment groups?
a. If no, describe what was done
b. What are the potential
consequences of this
assignment process for the
study’s results?
30. Did the investigators know who was
being assigned to which group prior to
the allocation?
a. If they were not blind, what are
the potential consequences of
this knowledge for the study’s
results?
31. Were the groups similar at the start of
the trial? Did they report the
demographics of the study groups?
a. If they were not similar – what
differences existed?
b. Do you consider these
differences a threat to the
research validity? How might
the differences between groups
affect the results of the study?
32. Did the subjects know to which
treatment group they were assign?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
33. Did the investigators know to which
treatment group subjects were
assigned?
a. If yes, what are the potential
consequences of the subjects’
again. The variance between the physiotherapists
was satisfactory with an average difference of 3
degrees, indicating satisfactory measurement
reliability in this study. Compensatory rivalry could
pose a threat because the subjects were not
blinded as to which group they were in.
Reader’s Comments
The patients were randomly allocated into two
groups with two different postoperative exercise
regimes, either CPM together with active
exercises (the experimental group) or active
exercises alone (the control group).
No, investigators did not know who was being
assigned to which group prior to the allocation.
The groups consisted of patients with
osteoarthritis admitted to Asker and Baerum
General Hospital for TKA between October 2003
and March 2005. They had the following inclusion
criteria: good cognitive function and fluent spoken
and written knowledge of Norwegian. Patients with
rheumatoid arthritis or prosthesis in the ipsilateral
hip were excluded. However, the demographics of
the groups are not reported in detail. 44 women
and 19 men completed the study, and the mean
age was 69 with a range of 49-92.
Yes, the subjects knew which treatment group
they were assigned to, due to the nature of the
CPM machine blinding of patients was not able to
be accomplished.
The assessing PT did not know to which group the
patient they were measuring outcomes on
belonged.
48
knowledge for this study’s
results
34. Were the groups managed equally,
apart from the actual experimental
treatment?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
35. Was the subject follow-up time
sufficiently long to answer the
question(s) posed by the research?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
36. Did all the subjects originally enrolled
complete the study?
a. If not how many subjects were
lost?
Yes, the groups were managed equally, apart from
the actual experimental treatment. Both underwent
the same surgical procedure, received the same
pain relief protocol, and participated in the same
exercise routine. The exercises were performed
daily, starting on day one after surgery, lasting for
30 min and the exercises were adjusted to the
patient’s degree of pain. The exercises consisted
of assisted and active flexion and extension of the
hip/knee, active isometric contraction of the
quadriceps, walking training using a high walker,
rollator or crutches, and eventually climbing stairs
on crutches. The experimental group was given
CPM treatment for the knee in flexion and
extension in addition to the active exercises. For
the passive movements, the patient lay in a supine
position with the operated leg in the CPM
machine. On the day of the operation the machine
was set at 70 – 100 degrees for flexion and the
knee was moved continuously for 2 hours x 2. The
next day the machine was set at 0 degrees to a
max 100 degrees of flexion, and the knee was
kept in movement continuously for 2 h x 3. These
were the usual clinical procedures in the hospital
concerned. Between sessions the knee was
placed in the extended position. The patients
stayed in hospital for a week, at the end of which
they could cope with dressing and grooming and
walk alone with a mechanical aid. All the patients
followed an exercise program with a local
physiotherapist after discharge. The out-patient
treatment was not standardized.
Yes, outcomes were measured at one week and 3
months after surgery, which is sufficient to
measure the short term effects.
No, 70 patients fit the inclusion criteria and were
invited to participate. 3 declined. 67 subjects
participated in the study and outcomes were
measured during hospitalization. 4 patients, 3
women and one man, were not measured at 3
49
b. What, if anything, did the
authors do about this attrition?
c. What are the implications of the
attrition and the way it was
handled with respect to the
study’s findings?
37. Were all patients analyzed in the groups
to which they were randomized (i.e. was
there an intention to treat analysis)?
a. If not, what did the authors do
with the data from these
subjects?
b. If the data were excluded, what
are the potential consequences
for this study’s results?
Are the valid results of this RCT important?
Appraisal Criterion
38. What were the statistical findings of this
study?
a. When appropriate use the
calculation forms below to
determine these values
b. Include: tests of differences
With p-values and CI
c. Include effect size with p-values
and CI
d. Include ARR/ABI and RRR/RBI
with p-values and CI
e. Include NNT and CI
f. Other stats should be included
here
39. What is the meaning of these statistical
findings for your patient/client’s case?
What does this mean to your practice?
months. 2 had died from heart and lung disease
and 2 did not attend the follow-up consultation.
The data on these 4 patients was withdrawn from
the study, so the results are based on the findings
from 63 pts, 44 women and 19 men. Mean age of
69, with a range 49-92. Due to the fact that the
data from these patients was withdrawn, this
should not affect the results.
Yes, all patients were analyzed in the groups to
which they were randomized.
Reader’s Comments
The data was analyzed with the Statistical
Passage for Social Sciences, version 12 for
Windows and showed a normal distribution. There
were no statistically significant differences
between the two groups in pain, range of motion
or swelling at one week or three months compared
with baseline (p>0.05). Nor were there any
statistically significant differences between the
groups in walking ability, which was measured by
the TUG, walking on a flat surface or climbing
stairs compared with baseline (p>0.05). Within
each group the range of motion in knee flexion
and extension after one week was significantly
smaller than at baseline (p<0.01). After three
months, flexion range of motion was improved
from one week, but still significantly lower than at
baseline (p<0.01). Within both groups pain
intensity was significantly lower after three months
than at baseline (p<0.01), but swelling in the knee
was more pronounced (p<0.01). The scores for
the TUG and the 40 m walking test had returned to
baseline values at three months (p>0.05).
These statistical findings mean that in this study
using a CPM did not improve functional outcomes
after TKA. The group who received active exercise
only had just as good of outcomes as the group
50
who received active exercise plus CPM.
Therefore, since the use of CPM did not improve
outcomes, its use is controversial in our practice
because how are we to justify its use if it does not
improve function and only increases costs and
uses more time and labor hours. Therefore, more
studies need to be done on the specific CPM
protocols and specific patients to see whether
CPM will have an effect in any cases or if we need
to discontinue the use of the CPM altogether.
The authors do not discuss the topic of MCID.
40. Do these findings exceed a minimally
important difference? Was this brought
up or discussed?
a. If the MCID was not met, will you
still use this evidence?
Can you apply this valid, important evidence about an intervention in caring for your
patient/client? What is the external validity?
Appraisal Criterion
Reader’s Comments
41. Does this intervention sound
Yes, this intervention of post-TKA PT, with or
appropriate for use (available,
without the use of a CPM protocol is appropriate in
affordable) in your clinical setting? Do
the clinical setting. However, more research needs
you have the facilities, skill set, time, 3rd to be done on specific CPM protocols and specific
party coverage to provide this
patients to assess whether the CPM provides any
treatment?
benefits and when it is indicated.
42. Are the study subjects similar to your
Yes, these patients are similar to my patient in that
patient/ client?
they have been diagnosed with OA, have
a. If not, how different? Can you
undergone TKA, have good cognitive function, and
use this intervention in spite of
were assessed in the acute care environment.
the differences?
43. Do the potential benefits outweigh the
Yes, I believe the potential benefits of using a
potential risks using this intervention
CPM machine, especially with a client like mine,
with your patient/client?
who has extremely limited ROM outweigh the
potential risks because the CPM protocol is not
risky or harmful.
44. Does the intervention fit within your
Yes, the intervention fits within my patient’s values
patient/client’s stated values or
to increase her ROM and functional outcomes.
expectations?
a. If not, what will you do now?
45. Are there any threats to external validity No, the external validity of this study is good.
in this study?
Patients were recruited consecutively at a local
hospital, and only 3 declined to participate, which
indicates there is very low probability of bias. Also,
the study consisted of 63 patients, which is higher
than the requisite sample number.
51
What is the bottom line?
Appraisal Criterion
PEDRO score (see scoring at end of form)
Summarize your findings and relate this back
to clinical significance
Reader’s Comments
8/10
This study found that as an adjunct to active
exercises did not have any additional beneficial
effects on pain, knee ROM, or walking ability
compared with active exercises alone neither at
one week nor at three months after TKA.
Therefore, more studies need to be done to
determine whether any CPM protocols improve
knee ROM and functional outcomes after TKA and
if specific patients will benefit from the use of CPM,
before CPM as an adjunct to PT is disregarded
altogether.
52
Intervention – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Denis, M. , Helene, M. , Caron, F. , Ouellet, D., Paquet, J., & Nolet, L. (2006). Effectiveness of continuous
Passive motion and conventional physical therapy after total knee arthroplasty: a randomized
Clinical trial. Physical Therapy, 86 (2), 175-185. http://ptjournal.apta.org/content/86/2/174.long
Level of Evidence (Oxford scale): 1b
Is the purpose and background information sufficient?
Appraisal Criterion
Reader’s Comments
Study Purpose
This RCT was conducted to compare the
Stated clearly?
effectiveness of 3 in-hospital rehabilitation
Usually stated briefly in abstract and in greater
programs with and without continuous passive
detail in introduction. May be phrased as a
motion (CPM) for knee flexion and extension range
question or hypothesis.
of motion (ROM), functional ability, and length of
A clear statement helps you determine if topic is
stay (LOS), after primary total knee arthroplasty
important, relevant and of interest to you. Consider (TKA).
how the study can be applied to PT and/or your
own situation. What is the purpose of this study?
Literature
Relevant background presented?
A review of the literature should provide
background for the study by synthesizing relevant
information such as previous research and gaps in
current knowledge, along with the clinical
importance of the topic.
Describe the justification of the need for this study
Yes, relevant background information is presented,
which describes the justification of the need for this
study. The effectiveness of the use of CPM s/p
TKA has been studied in a large variety of
protocols, with knee flexion ROM being the primary
outcome. Most studies have shown that CPM use
does not affect long-term ROM; however,
controversy still exists regarding CPM use and its
effectiveness on short-term ROM. Some studies
have reported significant knee flexion ROM gains
and faster knee flexion ROM recovery during the
hospital stay. Duration of CPM applications are
varied in these studies. Also, detailed methodology
has not consistently been described for
measurement of knee ROM. Some studies have
also shown that CPM use reduced LOS in acute
care. At the acute care facility in this study, the
effectiveness of CPM applications was questioned
when rehab protocols s/p TKA were revised. The
CPM was applied 35 minutes per day every day
until discharge. This facility was questioning
whether to maintain these low intensity CPM
53
applications s/p TKA. Therefore, this single-blind
RCT compared the effectiveness of 3 in-hospital
rehabilitation programs with various intensities of
CPM applications for knee flexion ROM, functional
ability, and LOS after primary TKA.
Does the research design have strong internal validity?
Appraisal Criterion
Reader’s Comments
Subjects were randomly assigned, so assignment
 Discuss possible threats to internal
should not affect internal validity. Instrumentation
validity in the research design. Include: could have posed a threat to internal validity
 Assignment
because goniometry was used to assess ROM.
 Attrition
Although, the protocol for goniometry was
 History
standardized: the fixed arm aligned with the
 Instrumentation
greater trochanter and the mobile arm aligned with
 Maturation
the lateral malleolus and the subject’s position was
 Testing
standardized, this could have affected internal
 Compensatory Equalization of
validity. Testing should not have affected internal
treatments
validity because the testers were blinded.
 Compensatory rivalry
Therefore, since assessors were blinded
 Statistical Regression
compensatory equalization of treatments should
not have affected internal validity. Compensatory
rivalry could have been an issue because the
subjects were not blinded. Statistical regression
should not have been an issue because subjects
were similar at baseline.
Are the results of this therapeutic trial valid?
Appraisal Criterion
46. Did the investigators randomly assign
subjects to treatment groups?
a. If no, describe what was done
b. What are the potential
consequences of this
assignment process for the
study’s results?
47. Did the investigators know who was
being assigned to which group prior to
the allocation?
a. If they were not blind, what are
the potential consequences of
this knowledge for the study’s
results?
Reader’s Comments
Yes, all subjects were randomly assigned to 1 of 3
groups immediately after TKA. The three groups
were: a control group, who received conventional
physical therapy (PT) intervention only;
experimental group 1, who received conventional
PT and 35 minutes of CPM applications daily; and
experimental group 2, which received conventional
PT and 2 hours of CPM applications day.
No, they did not. The subjects were recruited
based on eligibility decided on the basis of their
medical files obtained from the orthopedic
surgeons’ waiting list. Subjects were asked to
participate when they attended their routine
preoperative medical visit. They received prenumbered, sealed envelopes, which contained the
group assignment. Therefore, investigators did not
54
48. Were the groups similar at the start of
the trial? Did they report the
demographics of the study groups?
a. If they were not similar – what
differences existed?
b. Do you consider these
differences a threat to the
research validity? How might
the differences between groups
affect the results of the study?
49. Did the subjects know to which
treatment group they were assign?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
50. Did the investigators know to which
treatment group subjects were
assigned?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
51. Were the groups managed equally,
apart from the actual experimental
treatment?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
know who was being assigned to which group
prior to allocation.
The characteristics of and outcome measurements
for the subjects in the 3 groups were similar at
baseline. No significant difference among the 3
groups was demonstrated in primary or secondary
outcomes at discharge. Yes, the groups were
similar at baseline in all characteristics and
outcome measurements. There were no
statistically significant differences, which would
have affected outcomes.
Yes, the subjects knew to which treatment group
they were assigned because they received their
group assignment in a pre-numbered envelope.
No, assessors did not know to which treatment
groups the subjects were assigned. The design of
this study is a single-blind RCT. Assessments
were performed by 4 experienced PTs who were
unaware of group assignment.
Subjects in both experimental groups received one
daily CPM session, beginning on POD2 until d/c or
day 7 or 8. Nurses managed the COM and the
procedure was standardized. In the first group
(EXP1), CPM was used for 35 minutes
continuously, including a 5-minute warm-up
period. In the second group (EXP2), CPM was
used for 2 consecutive hours, including a 5-minute
warm-up period. On POD2 335-45 degrees of
flexion was reached with CPM for all subjects in
both groups. From POD 3 to d/c, increments of
ROM in flexion were determined by the PT on the
basis of maximal ROM in knee flexion during the
conventional PT intervention. All 3 groups
received the same daily, including weekends,
conventional PT intervention, which was
supervised by a physical therapist. On POD 1,
respiratory and circulatory exercises were
encouraged and isometric knee extensor muscle
exercises were performed, and extension knee
alignment was maintained in a splint. On POD2,
55
52. Was the subject follow-up time
sufficiently long to answer the
question(s) posed by the research?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
53. Did all the subjects originally enrolled
complete the study?
a. If not how many subjects were
lost?
b. What, if anything, did the
authors do about this attrition?
c. What are the implications of the
attrition and the way it was
handled with respect to the
study’s findings?
54. Were all patients analyzed in the groups
to which they were randomized (i.e. was
there an intention to treat analysis)?
a. If not, what did the authors do
with the data from these
subjects?
b. If the data were excluded, what
are the potential consequences
for this study’s results?
Are the valid results of this RCT important?
Appraisal Criterion
55. What were the statistical findings of this
study?
a. When appropriate use the
calculation forms below to
determine these values
b. Include: tests of differences
With p-values and CI
the splint was removed, AROM and PROM knee
flexion, and hip abduction and adduction in
horizontal plane was performed. Also, knee
extensor muscle exercises were performed.
Assistive device (AD) training, walking, and
transfers were then begun. Functional exercises
with weight bearing were added on POD 4, and if
needed, stair training was performed POD 6 or 7.
All subjects had to practice exercises and walk on
their own in addition to the supervised sessions.
Yes, because this study examines the use of CPM
in the acute care setting, the follow up time of 7-8
days s/p TKA, upon hospital d/c is sufficiently long
enough to answer the questions posed in this
study. The subjects were assessed twice by an
experience PT: once at the preoperative visit, 2-4
weeks before TKA, for baseline measurements
and again at discharge, 7-8 days after TKA.
No, one subject was excluded after being
randomly assigned by mistake; his preoperative
diagnosis was infection, not osteoarthritis, as
specified in the inclusion criteria. Therefore, from
February 2001-February 2003, 98 subjects were
evaluated at baseline: 82 were randomly assigned
to 1 of 3 groups. 27 were assigned to CTL, 26 to
EXP1, and 28 to EXP2. However, due to the 1
subject lost, 81 subjects were considered.
Yes, they were analyzed in the groups to which
they were randomized.
Reader’s Comments
No significant difference was found among the 3
groups in AROM knee flexion (p=.33). Also, no
significant difference was found among the 3
groups in AROM in knee extension (p=.30), in
TUG duration (p=.33), or in total (p=.28) and
subscale WOMAC questionnaire scores. No
significant difference was found in LOS (p=.83).
56
c. Include effect size with p-values
and CI
d. Include ARR/ABI and RRR/RBI
with p-values and CI
e. Include NNT and CI
f. Other stats should be included
here
56. What is the meaning of these statistical
findings for your patient/client’s case?
What does this mean to your practice?
These findings show that adding CPM applications
of low or moderate intensity to conventional PT
interventions has no short-term effect on AROM in
knee flexion or on secondary outcome
measurements of AROM knee ext, TUG results,
WOMAC questionnaire scores, and LOS.
Therefore, according to this study the use of CPM
This study did not discuss MCID.
57. Do these findings exceed a minimally
important difference? Was this brought
up or discussed?
a. If the MCID was not met, will you
still use this evidence?
Can you apply this valid, important evidence about an intervention in caring for your
patient/client? What is the external validity?
Appraisal Criterion
Reader’s Comments
58. Does this intervention sound
Yes, this intervention is appropriate for use in the
appropriate for use (available,
acute care clinical setting. PT treatment s/p TKA
affordable) in your clinical setting? Do
with or without the adjunct CPM treatment is
you have the facilities, skill set, time, 3rd appropriate in the acute care setting, and the
party coverage to provide this
facilities, skill set, time, and 3rd party coverage are
treatment?
available to help provide it.
59. Are the study subjects similar to your
Yes, the subjects were similar to my patient. They
patient/ client?
had a diagnosis of knee OA, underwent primary
a. If not, how different? Can you
TKA, were ambulatory, and were literate. They
use this intervention in spite of
underwent PT in an acute care setting, like my pt.
the differences?
60. Do the potential benefits outweigh the
Yes, the potential benefits of using CPM on
potential risks using this intervention
improving short term knee ROM and functional
with your patient/client?
outcomes s/p TKA may outweigh the potential
risks because CPM is not a risky procedure.
Therefore, more studies need to be done to
evaluate more protocols.
61. Does the intervention fit within your
Yes, this intervention fits within my patient’s values
patient/client’s stated values or
and expectations to increase her knee ROM and
expectations?
function.
a. If not, what will you do now?
57
62. Are there any threats to external validity No, were no threats to external validity that were
in this study?
identified.
What is the bottom line?
Appraisal Criterion
PEDRO score (see scoring at end of form)
Summarize your findings and relate this back
to clinical significance
Reader’s Comments
8/10
This study does not support the use of CPM as an
adjunct to conventional PT in rehabilitation
programs after primary TKA because they did not
further reduce knee impairments or disability or
reduce the length of the hospital stay. Therefore,
according to the results of this study, CPM should
not be used as an adjunct to conventional PT tx
because it does not improve short-term outcomes,
as evidenced by the lack of difference between the
control and experimental groups in outcomes, from
baseline to d/c from the hospital in pts s/p TKA.
Therefore, the use of CPM in the hospital is not
justified according to this study.
58
Systematic Review – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Grella, Ryan J. (2008). Continuous passive motion following total knee arthroplasty: a useful adjunct to
Early mobilisation?. Physical Therapy Reviews, 13(4), 269-279. doi: 10.1179/1743288o8X309197
Level of Evidence (Oxford scale): 1a
Does the design follow the Cochrane method?
Appraisal Criterion
Step 1 – formulating the question
• Do the authors identify the focus of the
review
• A clearly defined question should
specify the types of:
• people (participants),
• interventions or exposures,
• outcomes that are of interest
• studies that are relevant to
answering the question
Step 2 – locating studies
 Should identify ALL relevant literature
 Did they include multiple databases?
 Was the search strategy defined and
include:
o Bibliographic databases used
as well as hand searching
o Terms (key words and index
terms)
o Citation searching: reference
lists
Reader’s Comments
Yes, the focus of the review is to determine the
effectiveness of continuous passive motion (CPM)
following total knee arthroplasty when compared
to a rehabilitation protocol that permits early knee
mobilization and to determine if an optimal CPM
dosage schedule exists.
Participants: Patients had to be receiving a
primary total knee arthroplasty with a preoperative
diagnosis of osteoarthritis or rheumatoid arthritis.
Interventions: Both groups had to receive the
same physical therapy treatment that initiated
CPM and range of motion activities of the surgical
knee (whether active or passive) by postoperative
day two (POD2). This did not include quad sets or
straight leg raises (SLR).
Outcomes: Outcomes of interest are short and
long-term knee ROM, function, pain,
complications, length of hospital stay, and
quadriceps strength.
Studies: Only randomized control trials published
in the English language that compared physical
therapy plus CPM in the inpatient setting to a
control group who received just physical therapy
were included for review.
MEDLINE (1950-2007) AND CINAHL (1982-2007)
were searched electronically to find trials
investigating CPM after TKA. Therefore, only 2
databases were searched. Relevance was
achieved if an investigation compared CPM after
TKA to a control group which received on PT. All
trials classified as relevant were retrieved, and the
electronic search was further complemented by a
search of the reference lists of the retained
articles. Key words were: (1) continuous passive
motion, (2) CPM, (3) 1 or 2, (4) total knee
arthroplasty, (5) total knee replacement, (6) 4 or 5,
59
o Contact with ‘experts’ to identify
‘grey’ literature (body of
materials that cannot be found
easily through conventional
channels such as publishers)
o Sources for ‘grey literature’
Part 3:Critical Appraisal/Criteria for Inclusion
• Were criteria for selection specified?
• Did more than one author
assess the relevance of each
report
• Were decisions concerning
relevance described; completed
by non-experts, or both?
• Did the people assessing the
relevance of studies know the
names of the authors,
institutions, journal of
publication and results when
they apply the inclusion
criteria? Or is it blind?
Part 3 – Critically appraise for bias:
• Selection –
• Were the groups in the study
selected differently?
• Random? Concealed?
• Performance• Did the groups in the study
receive different treatment?
• Was there blinding?
• Attrition –
• Were the groups similar at the
end of the study?
• Account for drop outs?
• Detection –
• Did the study selectively report
the results?
• Is there missing data?
(7) 3 and 6, (8) limit 7 to (humans and English
language), (9) 7 and 8. The SR does not state
whether contact with experts to identify grey
literature occurred.
The methodological quality of investigations was
assessed by 3 reviewers using the Maastricht
Amsterdam Consensus List. This was the same
criteria list used in a systematic review of CPM
conducted by Lenssen et al. Each criterion was
scored as positive, negative, or unclear.
Disagreements were solved by majority vote. The
total score was tallied by adding up the number of
positive criteria. The systematic review (SR) does
not explicitly state whether or not the people
assessing the relevance of the studies knew the
names of the authors, institutions, journal of
publication and results when they applied the
inclusion criteria.
Selection: All groups in the study were involved in
a randomized control trial published in the English
language that compared PT plus CPM in the
inpatient setting to a control group who received
just PT. In addition patients had to be receiving aa
primary TKA with a preoperative diagnosis or OA
or RA.
Performance: Both groups had to receive the
same physical therapy treatment that initiated
CPM and range of motion activities of the surgical
knee (whether active or passive) by postoperative
day two (POD2). This did not include quad sets or
straight leg raises (SLR). There was not blinding of
patients or therapists in this study.
Attrition: Yes, the groups were similar at the end of
the study. Four of the eight investigations reported
equal co-interventions. For example, McInnes et
al. had unequal co-interventions at 6 weeks as 8
knees in the control group required manipulation.
In the study by Nielson et al. 54 patients started
the study, but 3 patients were excluded from
analysis because of cardiovascular complications,
a departure from the intention to treat principle.
60
Part 4 – Collection of the data
 Was a collection data form used and is
it included?
 Are the studies coded and is the data
coding easy to follow?
 Were studies identified that were
excluded & did they give reasons why
(i.e., which criteria they failed).
Are the results of this SR valid?
Appraisal Criterion
63. Is this a SR of randomized trials? Did
they limit this to high quality studies at
the top of the hierarchies
a. If not, what types of studies
were included?
b. What are the potential
consequences of including
these studies for this review’s
results?
64. Did this study follow the Cochrane
methods selection process and did it
identify all relevant trials?
a. If not, what are the
consequences for this review’s
results?
65. Do the methods describe the processes
and tools used to assess the quality of
individual studies?
a. If not, what are the
consequences for this review’s
results?
66. What was the quality of the individual
studies included? Were the results
consistent from study to study? Did
the investigators provide details about
the research validity or quality of the
studies included in review?
Detection: There does not appear to be selective
reporting or missing data in this SR.
Only randomized control trials published in the
English language that compared physical therapy
plus CPM in the inpatient setting to a control group
who received just physical therapy were included
for review. The characteristics of the eight
included studies are listed in table format.
However, the studies are not coded. Yes, studies
were identified that were excluded, and the
reasons they were excluded are given. They are
listed in a table given in the SR.
Reader’s Comments
Yes, this is an SR of RCTs. The inclusion criteria
for the RCTs are listed. Also, the methodological
quality of included investigations is included in a
table. All the studies, except one, that the authors
included were classified as high quality RCTs,
according to the Maastricht Amsterdam
Consensus List.
According to the 7 steps outlined in the Cochrane
Handbook, the systematic review follows the
steps. However, the investigators did not include
grey literature.
The methods say that the quality of investigations
was assessed by 3 reviewers using the Maastricht
Amsterdam Consensus List. Each criterion was
scored as positive, negative, or unclear.
Disagreements were solved by majority vote. The
total score was tallied by adding up the number of
positive criteria.
Yes, the quality of the individual studies is
included in a table. High-quality investigations
were RCTs that met 5 or more of the
methodological quality criteria. The results were
fairly consistent from study to study. There were
some conflicting results, but the authors were able
to come up with a conclusion
61
67. Did the investigators address
publication bias
Are the valid results of this SR important?
Appraisal Criterion
68. Were the results homogenous from study
to study?
a. If not, what are the
consequences for this review’s
results?
69. If the paper is a meta-analysis did they
report the statistical results? Did they
include a forest plat? What other
statistics do they include? Are there
CIs?
70. From the findings, is it apparent what
the cumulative weight of the evidence
is?
No, they did not address publication bias.
Reader’s Comments
There was strong evidence that CPM exerts no
influence on short and long-term knee extension,
long-term knee flexion, long-term function, pain,
complications, and length of hospital stay when
compared to a rehabilitation protocol that permits
early knee mobilization. Data for short-term knee
flexion, quadriceps strength, and short-term
function were conflicting. Preliminary evidence
suggests that CPM applied immediately
postoperatively, at a high flexion arc of motion,
and for a significant amount of time each day
leads to better outcome with regards to short-term
knee flexion. Therefore, the data for most outcome
measurements was homogeneous, but there was
some conflicting outcome measurements among
the studies. Therefore, further studies need to be
done to determine conclusion about whether or
not CPM use is beneficial and cost-effective. In
order to truly examine the putative effects of CPM
following TKA a more aggressive CPM
intervention needs to be employed: one in which it
is applied immediately postoperatively, at a high
flexion arc of motion, and for a significant amount
of time each day. If the results of this trial prove to
be clinically significant, then the increased time on
the machine may prove to be beneficial;
conversely, if little or no effect is shown then the
continued use of CPM following TKA should be
questioned as an unnecessary adjunct.
A meta-analysis was not employed as it was
believed there was too much variability in tests,
measures, and time frames to pool results. Instead
outcomes were summarized by a rating system
comprising four levels of scientific evidence.
Yes, it is clear that the data for most outcome
measurements was homogenous, but there was
some conflicting evidence among the studies.
However, overall CPM as an adjunct did not
improve long-term outcomes. Preliminary
evidence suggests that CPM applied immediately
postoperatively, at a high flexion arc of motion,
62
and for a significant amount of time each day
leads to better outcome with regards to short-term
knee flexion.
Can you apply this valid, important evidence from this SR in caring for your patient/client? What
is the external validity?
Appraisal Criterion
Reader’s Comments
71. Is your patient different from those in
My patient is similar to those in the SR in that I
this SR?
saw her in the inpatient setting. She had
undergone a TKA with a primary diagnosis of
osteoarthritis. She received PT treatment, as well
as CPM use on the surgical knee POD0. However,
she was encouraged to perform quad sets, which
was one of the exercises that was excluded from
the studies that were analyzed.
72. Is the treatment feasible in your
Yes, physical therapy treatment and CPM use is
setting? Do you have the facilities, skill feasible in the inpatient setting. The time, skill set,
set, time, 3rd party coverage to provide
and third party coverage is available.
this treatment?
73. Does the intervention fit within your
Yes, this treatment fits with my patient’s stated
patient/client’s stated values or
values and expectations to increase her surgical
expectations?
knee ROM.
b. If not, what will you do now?
What is the bottom line?
Appraisal Criterion
Summarize your findings and relate this back
to clinical significance
Reader’s Comments
Three of seven trials investigating short-term knee
flexion outcomes reported significant differences in
favor of CPM. None of the trials reported a
difference in long-term knee flexion outcomes;
however one of the eight trials did report that the
control group had significantly less knee extension
on postoperative day 17. No differences in shortterm knee extension outcomes were identified.
The effects of CPM use on pain were conflicting. 6
trials reported no differences in pain or analgesic
requirements. 1 trial reported that CPM use led to
an increase in analgesic requirement at 1 week. 1
trial reported conflicting results that CPM
decreased pain levels at POD4 and 17.
Only 1 of the 5 trials that used complications as an
outcome measure found a significant difference
between groups. McInnes et al. found that CPM
reduced the need for manipulation: 8 knees in the
control group required manipulation compared to
none in the CPM group.
63
2 trials used quadriceps strength as an outcome
measure, and had conflicting results. 1 trial
reported no difference, while the other trial
reported increased quad strength at POD4 with
CPM use.
6 trials investigated CPM use and its effect on
function: short term was assessed in 3 and longterm in 5. Only 1 trial found significant findings in
favor of CPM with regards to short and long term
function. 5 trials examined length of stay in hospital
and none reported a significant difference between
groups. CPM was shown to have no additional
benefit in terms of short and long-term knee
extension, long-term knee flexion, long term
function, pain, complications, and length of hospital
stay. This was supported by strong evidence.
Effects upon short-term knee flexion, quadriceps
strength, and short-term function proved to be
inconclusive as evidence was conflicting. However,
preliminary evidence suggests that CPM applied
immediately postoperatively, at a high flexion arc
of motion, and for a significant amount of time
each day exerts a greater effect on outcomes.
Clinical Significance: Therefore, it would be
beneficial to my patient to have a CPM applied
immediately postoperatively, at a high flexion arc,
and for a significant amount of time, in the acute
care environment. This may help her improve
short-term knee flexion and function.
64
Systematic Review – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Harvey, L.A., Brosseau, L., P& Herbert, R.D. (2014). Continuous passive motion following total knee
arthroplasty in people with arthritis (Review). Cochrane Database of Systematic Reviews 2,
1-121. doi: 10.1002/14651858.CD004260.pub3.
Level of Evidence (Oxford scale): 1A
Does the design follow the Cochrane method?
Appraisal Criterion
Step 1 – formulating the question
• Do the authors identify the focus of the
review
• A clearly defined question should
specify the types of:
• people (participants),
• interventions or exposures,
• outcomes that are of interest
• studies that are relevant to
answering the question
Reader’s Comments
Yes, the focus of the review is to assess the
benefits and harms of CPM and standard
postoperative care versus similar postoperative
care, with or without additional knee exercises, in
people with knee arthroplasty. This review is an
update of a 2003 and 2010 version of the same
review.
Participants: Participants could be of any age
provided they were hospitalized following TKA. All
participants needed to have a pre-surgery
diagnosis of arthritis.
Interventions: Randomized controlled trials in
which the experimental group received CPM, and
both the experimental and control groups received
similar postoperative care and therapy following
total knee arthroplasty in people with arthritis. We
included only randomized controlled trials (RCT),
regardless of language. We accepted abstracts.
We did not exclude trials based on quality
assessment.
Outcomes: The primary outcomes of interest
were active knee flexion ROM, pain, quality of life,
function, participants’ global assessment of
treatment effectiveness, incidence of manipulation
under anesthesia and adverse events? The
secondary outcomes were passive knee flexion
ROM, active knee extension ROM, passive knee
extension ROM, length of hospital stay, swelling
and quadriceps strength.
Relevant Studies: Trials were included if CPM and
standard postoperative care were compared with
similar postoperative care with or without
additional knee exercises. Standard postoperative
care could include muscle-strengthening exercises
65
(isometric or dynamic), functional exercises, gait
training, immobilization or ice, provided both
groups received the same intervention. Additional
knee exercises could include instructions or
supervised active or passive knee
ROM exercises. They could not include knee
exercises provided with any type of CPM device.
Step 2 – locating studies
The following databases were searched: the
Cochrane Central Register of Controlled Trials
 Should identify ALL relevant literature
(CENTRAL) (The Cochrane Library 2012,
 Did they include multiple databases?
Issue 12), MEDLINE (January 1966 to 24 January
 Was the search strategy defined and
2013), EMBASE (January 1980 to 24 January
include:
2013), CINAHL (January 1982 to
o Bibliographic databases used
24 January 2013), AMED (January 1985 to 24
as well as hand searching
January 2013) and PEDro (to 24 January 2013).
o Terms (key words and index
684 papers were identified from the electronic
terms)
searches after removal of duplicates and retrieved
o Citation searching: reference
the full reports of 62 potentially eligible trials.
lists
o Contact with ‘experts’ to identify Twenty-four randomized controlled trials of 1445
participants met the inclusion criteria; four of these
‘grey’ literature (body of
trials were new to this update. The reference lists
materials that cannot be found
of all included trial were checked for other
easily through conventional
potentially relevant trials. We attempted to contact
channels such as publishers)
all study authors to clarify any ambiguities.
o Sources for ‘grey literature’
Part 3:Critical Appraisal/Criteria for Inclusion
• Were criteria for selection specified?
• Did more than one author
assess the relevance of each
report
• Were decisions concerning
relevance described; completed
by non-experts, or both?
• Did the people assessing the
relevance of studies know the
names of the authors,
institutions, journal of
publication and results when
they apply the inclusion
criteria? Or is it blind?
Part 3 – Critically appraise for bias:
• Selection –
• Were the groups in the study
selected differently?
• Random? Concealed?
• Performance-
Two independent review authors examined the
titles and abstracts of trials identified by the search
strategy for trials that potentially met the inclusion
criteria. All trials classified as potentially eligible by
at least one of the review authors were retrieved.
The retrieved articles were examined to ensure
that they met the inclusion criteria. Two review
authors independently assessed the risk of bias in
each trial using the method recommended in the
Cochrane Handbook for Systematic Reviews of
Interventions. The review does not state whether
or not the reviewers were experts or whether or
not they knew the names of the authors,
institutions, journal of publication and results when
they applied the inclusion criteria.
Two review authors independently assessed the
risk of bias in each trial using the method
recommended in the Cochrane Handbook for
Systematic Reviews of Interventions. The
following methodological domains were assessed:
1. random sequence generation;
66
Did the groups in the study
receive different treatment?
• Was there blinding?
Attrition –
• Were the groups similar at the
end of the study?
• Account for drop outs?
Detection –
• Did the study selectively report
the results?
• Is there missing data?
2. allocation sequence concealment;
3. blinding of participants;
4. blinding of therapists;
5. blinding of outcome assessors;
6. incomplete outcome data;
7. selective outcome reporting; and
8. other potential sources of bias.
The potential source of bias was rated as high, low
or unclear (either lack of information or uncertainty
over the potential for bias). The investigators
attempted to contact all study authors to clarify
any ambiguities. Disagreements were resolved by
discussion or, where necessary, by consulting a
third review author.
Selection: In trials with more than two groups, data
was only extracted from the two groups with the
most contrasting interventions and used these for
analyses. For example, in trials with one control
and two CPM groups, investigators included only
the results of the control group and CPM group
with the highest dosage in analyses. Investigators
adopted this approach to reduce complexity and
increase the readability of the systematic review.
Performance: No trial blinded patients or treating
therapists as this is not easily achievable in trials
of this type. Probably the biggest threat to bias in
trials of CPM come from the use of non-blinded
assessors and only 10 trials blinded assessors.
Attrition:
Detection: Selective reporting was potentially a
problem in 16 of the 24 trials and there was
incomplete reporting of data in at least eight trials.
Part 4 – Collection of the data
 Was a collection data form used and is
it included?
 Are the studies coded and is the data
coding easy to follow?
 Were studies identified that were
excluded & did they give reasons why
(i.e., which criteria they failed).
Yes, there was a collection data form used and it
is included in the review. The studies are coded in
an easy to follow manner, so that the data from
each study is easy to read, reference, and
interpret. Authors did identify the studies that were
excluded. These studies were listed in a table,
along with the reason for their exclusion.
•
•
•
Are the results of this SR valid?
Appraisal Criterion
Reader’s Comments
67
74. Is this a SR of randomized trials? Did
they limit this to high quality studies at
the top of the hierarchies
a. If not, what types of studies
were included?
b. What are the potential
consequences of including
these studies for this review’s
results?
75. Did this study follow the Cochrane
methods selection process and did it
identify all relevant trials?
a. If not, what are the
consequences for this review’s
results?
76. Do the methods describe the processes
and tools used to assess the quality of
individual studies?
a. If not, what are the
consequences for this review’s
results?
Yes, it is an SR of RCTs. The methodological
quality of trials was variable. Only 10 trials clearly
blinded assessors. Not surprisingly, given the
nature of the intervention, no trial blinded
participants or therapists. Failure to blind
assessors, participants and therapists exposes the
trials to performance and detection biases. The
failure to blind participants is potentially more of
problem for outcomes that rely on self-report (such
as pain) than more objective measures (such as
passive knee ROM). Only eight of the 24 trials
concealed allocation and nearly all trials were
selective in their reporting of data. These potential
sources of bias led to a downgrading of the quality
of evidence for all outcomes.
Yes, this study followed the Cochrane methods of
selection process and identified all relevant
articles.
The GRADE approach was used to summarize the
quality of evidence about the effect of CPM on
each of the primary outcomes (active knee flexion
ROM, pain, function, quality of life, participants’
global assessment of treatment effectiveness,
need for manipulation under anesthesia and
adverse events). We used the short-term effects in
the analyses except for function and quality of life
where we used the medium-term effects because
either there were no data for the short-term effects
or the data could not befouled because of
heterogeneity. We defined levels of quality as
follows:
1.high quality: randomized trials;
2. medium quality: downgraded randomized trials;
3. low quality: double-downgraded randomized
trials; and
4. very low quality: triple-downgraded randomized
trials.
The quality of evidence was downgraded if:
1. there were limitations in the design and
implementation of
available trials suggesting high likelihood of bias;
2. there was only indirect evidence (indirect
population,
68
intervention, control, outcomes);
3. there was unexplained heterogeneity or
inconsistency of
results (including problems with subgroup
analyses);
4. the results were imprecise (wide CIs); and
5. there was a high probability of publication bias.
In the same way, the quality of evidence was
upgraded if:
1. the effect sizes were large;
2. all confounding factors reduced a demonstrated
effect or
suggested a spurious effect in trials that showed
no effect; and
3. there was a dose-response gradient.
We used GRADEpro software to compile the
’Summary of findings’ table.
77. What was the quality of the individual
studies included? Were the results
consistent from study to study? Did
the investigators provide details about
the research validity or quality of the
studies included in review?
78. Did the investigators address
publication bias
Are the valid results of this SR important?
Appraisal Criterion
79. Were the results homogenous from
study to study?
a. If not, what are the
consequences for this review’s
results?
80. If the paper is a meta-analysis did they
report the statistical results? Did they
include a forest plat? What other
Yes, the quality of the individual studies was
included in a table, and the results were consistent
from study to study.
Yes, a risk of bias graph was included in the
review and it included bias from selection, attrition,
reporting, participant, personnel, and assessor
blinding.
Reader’s Comments
There was usually a high degree of consistency
(low between-study heterogeneity) in estimates of
effects of pooled findings. Heterogeneity was only
apparent in a small number of comparisons,
typically where SMDs were used and when total
sample sizes were small. The heterogeneity could
have been due to any number of factors but was
most likely due to the use of different tools to
measure the same construct. This was particularly
problematic for function, which was measured with
outcomes as diverse as self-reporting
questionnaires and timed walking tests.
Yes, the statistical results were reported.
However, the authors did not include a forest plot.
CIs are included for the data, though.
69
statistics do they include? Are there
CIs?
81. From the findings, is it apparent what
the cumulative weight of the evidence
is?
The findings of 24 RCTs of 1445 participants
provide moderate-quality evidence that CPM does
not have clinically important short-term effects on
active knee flexion ROM or medium-term effects
on function or quality of life. There is low-quality
evidence to indicate that CPM does not have
clinically important short term effects on pain. The
effects of CPM on participants’ global
assessment of treatment effectiveness, risk of
manipulation, risk of adverse events, length of
hospital stay, swelling and quadriceps strength
remain unclear although there is very low-quality
evidence to indicate that CPM reduces the risk of
manipulation under anesthesia.
Can you apply this valid, important evidence from this SR in caring for your patient/client? What
is the external validity?
Appraisal Criterion
Reader’s Comments
82. Is your patient different from those in
The patients in the studies could be of any age
this SR?
provided they were hospitalized following TKA and
had a pre-surgery diagnosis of arthritis. Therefore,
my patient is similar to those patient included in
the studies because she was hospitalized
following TKA and had a pre-surgery diagnosis of
arthritis.
83. Is the treatment feasible in your
Yes, physical therapy treatment and CPM use is
setting? Do you have the facilities, skill feasible in the inpatient setting. The time, skill set,
set, time, 3rd party coverage to provide
and third party coverage is available.
this treatment?
84. Does the intervention fit within your
My patient’s values were to improve her knee
patient/client’s stated values or
ROM and function following her TKA. Therefore,
expectations?
anything that improves her function and ROM fits
c. If not, what will you do now?
within her stated values and expectations.
What is the bottom line?
Appraisal Criterion
Summarize your findings and relate this back
to clinical significance
Reader’s Comments
The findings of 24 RCTs of 1445 participants
provide moderate-quality evidence that CPM does
not have clinically important short-term effects on
active knee flexion ROM or medium-term effects
on function or quality of life. There is low-quality
evidence to indicate that CPM does not have
70
clinically important short term effects on pain. The
effects of CPM on participants’ global
assessment of treatment effectiveness, risk of
manipulation, risk of adverse events, length of
hospital stay, swelling and quadriceps strength
remain unclear although there is very low-quality
evidence to indicate that CPM reduces the risk of
manipulation under anesthesia. The effects of
continuous passive motion (CPM) on range of
motion (ROM), pain, function and quality of life are
too small to justify its use and costs but the effects
of CPM on participants’ global assessment of
treatment effectiveness are unclear. This review
provides very low-quality evidence that CPM
reduces the risk of manipulation under anesthesia;
however, these findings need to be interpreted with
caution because they are inconsistent with the
moderate-quality evidence indicating that CPM has
no effect on knee ROM, even though the main
indication for manipulation under anesthesia is
joint stiffness.
71
Prognostic Study – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Herbold, J. A. , Bonistall, K. , & Blackburn, M. (2012). Effectiveness of continuous passive motion in an
Inpatinet rehabilitation hospital after total knee replacement: a matched cohort study. American
Academy of Physical Medicine and Rehabilitation, 4, 719-725.
http://dx.doi.org/10.1016/j.pmrj.2012.07.004
Level of Evidence (Oxford scale): 2b
Is the purpose and background information sufficient?
Appraisal Criterion
Reader’s Comments
Study Purpose
Yes, the purpose is stated clearly. The purpose of
Stated clearly?
this study is to examine the use of continuous
Usually stated briefly in abstract and in greater
passive motion (CPM) as an adjunct to physical
detail in introduction. May be phrased as a
therapy after total knee replacement in patients
question or hypothesis.
who were transferred to an inpatient rehabilitation
A clear statement helps you determine if topic is
facility (IRF) and to compare the effectiveness of
important, relevant and of interest to you. Consider CPM on active range of motion (AROM), functional
how the study can be applied to PT and/or your
tasks, destination after discharge, the need for
own situation. What is the purpose of this study?
home care services, and the ambulation device at
discharge.
Literature
Relevant background presented?
A review of the literature should provide
background for the study by synthesizing relevant
information such as previous research and gaps in
current knowledge, along with the clinical
importance of the topic.
Describe the justification of the need for this study
Yes, relevant background information is presented.
Previous research has shown that most functional
activities require >90 degrees of knee flexion.
Therefore, a goal of post-acute therapy is to
improve ROM to assist with functional activities.
Salter and Coutts have postulated that the CPM
enhanced collagen tissue healing and better fiber
orientation, resulting in improved ROM. Another
study has shown that CPM as an adjunct to PT
improves soft-tissue healing, swelling,
hemarthrosis, and joint function. Although the
results are conflicting, the studies in which patients
received CPM immediately after surgery
demonstrated greater short-term knee flexion
compared to their counterparts who did not receive
CPM, upon discharge from acute-care. However,
studies in which CPM was initiated later do not
show any difference between the use of CPM and
PT alone. However, issues with the CPM-use
studies include a lack of consistency in the
72
protocol of application, inconsistency in the time
frame of data collection, and variability in the
outcome data variables that were compared.
Despite the lack of and conflicting evidence for its
effectiveness, CPM continues to be used in postacute venues, even though all of the studies from
the IRF show no additional benefit in adding CPM
to traditional PT alone. Due to the fact that at this
facility, CPM is provided for patients who are
admitted for rehab with initial poor ROM <75
degrees, this study aims to look at the current
practice of CPM use and its effectiveness, amid
the controversy.
Does the research design have strong sampling techniques?
Appraisal Criterion
Reader’s Comments
Did the investigators provide sufficient information Yes, with use of matching criteria, this study
to describe the sample in their study?
identified 61 pairs of patients who completed their
Does the study clearly define the group of rehabilitation stay in the IRF. The sample was
patients; is there a clear inclusion and
selected based on pts s/p TKR with less than 75
exclusion criterion? Is there a clear
degrees of flexion (n=633). Then, the sample was
description of the stage and timing of the
divided into those who did not receive CPM as an
problem (illness) studied.
adjunct to therapy (yes=181 and no=452). From
these 2 groups, CPM and non-CPM, pts were
matched on initial flexion ROM, postoperative
days, age, LOS, and Health Insurance Prospective
Payment System (HIPPS) code, which generates
a combined functional and comorbidity index. 9 pts
were excluded because they were transferred to
acute care due to complications. Therefore, from
this they generated an n=61 matched pairs (122
total pts). Exclusion criteria included a LOS in the
IRF shorter than 3 days, age younger than 40
years, and documented comorbid conditions that
might negatively affect the functional outcomes
and ROM of the pts such as Parkinson’s disease,
multiple sclerosis, COPD, and concurrent stroke.
Are the subjects representative of the population
Yes, subjects are representative of the population
from which they were drawn?
from which they were drawn. The study selected
Did they capture all eligible subjects?
pts who were admitted to a rehabilitation facility
directly from an acute care hospital after TKR
between 2008 and 2009. The facility provided
medical rehabilitation services for patients who are
unable to go directly home from the acute care
hospital post TKR.
73
Are the results of this prognostic study valid?
Appraisal Criterion
Reader’s Comments
1. Were the subjects assembled at a
Yes, all subjects were assembled upon admission
common (usually early) point in the
to an IRF s/p TKR.
course of their disorder?
a. If not, what are the implications
of multiple starting points for this
study’s results?
2. Was the study time frame long enough
to capture the outcome(s) of interest?
Was patient follow-up sufficiently long
and complete?
a. If not, what are the potential
consequences of the follow-up
time for the study’s results?
3. Did all subjects originally enrolled
complete the study?
a. If not, how many subjects were
lost
b. What if anything did the authors
do about this attrition?
c. What are the implications of this
attrition and the way it was
handled with respect to the
study’s findings?
Yes, outcome measures were examined at
discharge from the IRF, which would give an
adequate picture of the short-term outcomes of
using vs not using a CPM in the IRF setting.
Not all patients whose data was examined were
included in the study because researchers used a
matched cohort design to match patients in the 2
groups. Also, some pts were excluded if they had
a LOS in the IRF shorter than 3 days, age younger
than 40 years, and documented comorbid
conditions that might negatively affect the
functional outcomes and ROM of the pts such as
Parkinson’s disease, multiple sclerosis, chronic
obstructive pulmonary disease, and concurrent
stroke.
4. Were objective outcome criteria applied The study does not specifically state whether
to the subjects in a masked or blinded
assessors knew whether the pts had received
fashion??
CPM as an adjunct tx or not. However, because
a. If not, what are the potential
this study looked at outcomes retrospectively, this
consequences for this study’s
should not have biased the results because the
results
study was done retrospectively, using data
obtained of patients’ medical record. However, it
may have biased the results if assessors were
aware of the intention of the study, while they were
measuring outcome measures on the pts.
5. If subgroups with different prognoses
The 2 groups had the same prognosis. No
are identified, was there adjustment for
statistically significant differences in outcomes
important prognostic or risk factors?
were found. Also, the groups were similar in all
a. If not, what should have been
variables, and they demonstrated no statistically
included? What are the potential significant differences, except in race. The nonconsequences for the lack of this CPM group had a greater Hispanic/Latino
adjustment
component (p=.05). Therefore all outcome
variables did not demonstrate statistically
significant differences, so the research validity
should not be affected.
74
6. Was there an independent set of patients
to validate the study?
a. If not, what are the potential
consequences for this study’s
results?
There was a control group, who did not receive
CPM as an adjunct to traditional PT tx. However,
there was not an independent group of pts, who
received no tx s/p TKR. Both groups (CPM and
no-CPM) received physical therapy; however, PT
protocols may have differed base on the individual
pt and the PT providing the therapy. The CPM
group received the CPM therapy while in the
supine position for 2 hours per day, with treatment
initiated on the second day of their rehab stay and
continued until discharge. The ROM settings were
increased daily or as needed by the PT as
tolerated by the pt. The pt also had access to the
on-an-off switch and could terminate the
intervention because of pain or intolerance.
Therefore, because PT protocols were not
described in detail for this study, they may have
differed, thereby affecting the outcomes. Also,
because CPM could be terminated by the pt, this
may have affected outcomes because some of the
pts may not have used their CPM as described in
the study, causing there to be no difference
between groups.
Are the valid results of this prognostic study important?
Appraisal Criterion
Reader’s Comments
7. What were the statistical findings of this No statistically significant differences in any of the
study?
outcome variables compared in this matched case
a. When appropriate use the
design were found, including AROM knee flexion
calculation forms below to
at d/c, flexion gain, d/c AROM extension,
determine these values
extension gain, d/c to community, need for home
b. Report on correlation coefficient care after d/c, and d/c with a cane/no device. Also,
and/or coefficient of
no statistically significant difference was fund in
determination
any of the functional scores as measured by the
c. Did they include a survival curve, FIM subscales and total FIM, as well as the motor,
ROC, odds ratios, relative risk
cognitive, or total FIM gain.
ratio
d. How precise are the CIs?
e. Other stats should be included
here
8. What is the meaning of these statistical
findings for your patient/client’s case?
What does this mean to your practice?
These results do not support the use of CPM in an
IRF as an adjunct to PT after TKR because they
show that in a matched sample of pts admitted to
an IRF after surgery with poor initial AROM, no
significant difference was found in any of the
outcome variables: d/c flex AROM, flex AROM
75
gain from admission to d/c, FIM, d/c amb device,
d/c to community, or use of home care services.
Can you apply this valid, important evidence about this prognostic study in caring for your
patient/client? What is the external validity?
Appraisal Criterion
Reader’s Comments
9. How likely are these outcomes over
The outcome measurements are likely to improve
time?
with time s/p TKA. It is also likely that there would
be no statistically significant difference between
groups, like this study found, which seems to be
the consensus of the research.
10. Are the study subjects similar to your
Yes, the subjects were similar to my pt in that they
patient/ client?
were admitted to an IRF s/p TKR and had knee
a. If not, how different? Can you
flexion AROM <75 degrees upon admission.
use this test in spite of the
Although this description fits my pt, I saw my pt in
differences?
the acute care setting, and these pts were seen in
the IRF pt setting.
11. Would sharing this information help your Yes, the intervention fits within my patient’s stated
patient/client given their expressed
values to increase her knee ROM and functional
values and preferences?
outcomes s/p TKR. Although, this study showed
no benefit to CPM use, but the potential benefits
may outweigh the potential risks. More research
needs to be done. However, CPM is not a risky
procedure.
What is the bottom line?
Appraisal Criterion
Summarize your findings and relate this back to
clinical significance and usefulness of this study
Reader’s Comments
In an IRF setting the application of a CPM protocol
as an adjunct to traditional PT treatment, does not
improve functional outcomes in pts with AROM knee
flexion <75 degrees. Therefore, according to this
study, CPM used as an adjunct treatment does not
improve d/c AROM flex or ext, flex or ext gain, d/c to
community, need for home care, d/c with cane vs no
AD, or d/c FIM scores. Therefore, CPM as an adjunct
to PT tx in the IRF setting, with pts with poor initial
knee flexion AROM, does not statistically or clinically
improve functional outcomes. Therefore, the use of a
CPM in the IRF, with pts with poor initial AROM knee
flex, is only using up resources and time.
76
Intervention – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Herbold, J. A., Bonistall, K., Blackburn, M., Agolli, J., Gaston, S., Gross, C., …Babyar, S. (2014).
Randomized controlled trial of the effectiveness of continuous passive motion after total
knee replacement. Archives of Physical Medicine and Rehabilitation, 95, 1240-5. doi:
http://dx.doi.org/10.1016/j.apmr.2014.03.012
Level of Evidence (Oxford scale): 1B
Is the purpose and background information sufficient?
Appraisal Criterion
Reader’s Comments
Study Purpose
The investigators clearly state the purpose of this
Stated clearly?
study, which is to determine the effects of using a
Usually stated briefly in abstract and in greater
continuous passive motion (CPM) device for
detail in introduction. May be phrased as a
individuals with poor range of motion (ROM) after a
question or hypothesis.
total knee replacement (TKR) admitted for postA clear statement helps you determine if topic is
acute rehabilitation.
important, relevant and of interest to you. Consider
how the study can be applied to PT and/or your
own situation. What is the purpose of this study?
Literature
Relevant background presented?
A review of the literature should provide
background for the study by synthesizing relevant
information such as previous research and gaps in
current knowledge, along with the clinical
importance of the topic.
Describe the justification of the need for this study
The investigators provide relevant background
information. Due to the fact that the number of
TKR surgeries is on the rise, there is more demand
for rehabilitation services for these patients. CPM
is normally part of the acute rehab protocol for
physical therapy (PT). However, there is a lack of
studies and evidence on the use of CPM in postacute rehabilitation facilities. Also, there is
conflicting evidence as to the effectiveness of the
CPM is improving knee ROM after TKR. The
investigators cite studies that show positive short
term results when the CPM is applied in the acute
setting. They also cite studies that refute the
effectiveness of CPM when applied in the acute
setting. No prior CPM study has been conducted in
an inpatient rehab facility in selected patients most
at risk for poor knee ROM after TKR.
Does the research design have strong internal validity?
Appraisal Criterion
Reader’s Comments
77
 Discuss possible threats to internal
validity in the research design. Include:
 Assignment
 Attrition
 History
 Instrumentation
 Maturation
 Testing
 Compensatory Equalization of
treatments
 Compensatory rivalry
 Statistical Regression
Assignment: All patients transferred directly to the
IRF within 5 days after their surgery between
November 2011 and November 2012 were
assigned a primary PT who assess the patient’s
active knee flexion and extension ROM on the day
of admission. Patients were then enrolled
consecutively according to the following inclusion
criteria: 1) transferred to an IRF after a single knee
replacement; 2) etiology of osteoarthritis; 3) aged
40-80 years old; 4) initial maximal knee flexion
ROM between 45° and 75° of flexion; and 5) BMI
<40. Exclusion criteria: 1) revision to a previous
TKR; 2) bilateral TKR; 3) comorbid medical
conditions that could interfere or complicate
recovery. The institutional review board approved
the study, and written informed consent was
obtained for each participant. Consented subjects
were then randomly assigned to either the control
or experimental group based on their unique,
episode-specific account number. Therefore,
group assignment was random and groups were
similar, so assignment should not affect the
internal validity.
Attrition: 145 subjects enrolled in the study and 4
were unable to complete the study. 2 subjects
withdrew due to intolerance of CPM. No reason
was given for the other 2 withdrawals. The
researchers do not explicitly say whether the data
from these patients was included in the study
results. Also, in the control group 52 patients
completed the WOMAC on admission, but only 34
returned it, and 57 CPM subjects completed the
WOMAC on admission, but only 40 returned it.
History: The subjects included in this study were
transferred from an acute care hospital to the IRF,
and the IRF staff did not have access to presurgical ROM or preoperative knee alignment.
Instrumentation: The intertester reliability of ROM
measurements of the staffed physical therapists
was not evaluated. Although, the unit was staffed
by a consistent group of 4-5 physical therapists
who were trained in standard goniometric
measurement protocol. Therefore, pre-selection of
78
patients with ROM <75°at the start of the study
and the error associated with goniometric
measurement may have resulted in a regression
of the mean for flexion at discharge. Also, despite
encouraging CPPM use in the evening, patients
had the ability to terminate the treatment prior to
the prescribed 2 hours per day.
Maturation: Outcome measurements were
assessed at initial evaluation and a day prior to
discharge. Therefore, no threats to maturation
exist because patients were only exposed to the
outcomes assessments 2 times.
Testing: The study does not explicitly state
whether it was the same PT who performed the
initial assessment and the discharge assessment.
Therefore, this could affect internal validity due to
human measurement error.
Compensatory Equalization of treatments: The
study avoided threats to internal validity in this
area by providing subjective (WOMAC) and
objective (ROM, TUG, girth, FIM, ambulation
device, length of stay) measures of functional
outcomes after TKR.
Compensatory Rivalry: The study does not
explicitly state whether or not the control and
treatment groups knew the differences in their
treatment. Therefore, compensatory rivalry is a
possible threat to internal validity.
Statistical Regression: Pre-selection of patients
with ROM <75° at the start of the study and the
error associated with goniometric measurement
may have resulted in a regression of the mean for
flexion at discharge.
Are the results of this therapeutic trial valid?
Appraisal Criterion
85. Did the investigators randomly assign
subjects to treatment groups?
a. If no, describe what was done
Reader’s Comments
Yes, subjects were randomly assigned to
treatment groups based on their unique, episodespecific account number. The control group
79
b. What are the potential
consequences of this
assignment process for the
study’s results?
86. Did the investigators know who was
being assigned to which group prior to
the allocation?
a. If they were not blind, what are
the potential consequences of
this knowledge for the study’s
results?
87. Were the groups similar at the start of
the trial? Did they report the
demographics of the study groups?
a. If they were not similar – what
differences existed?
b. Do you consider these
differences a threat to the
research validity? How might
the differences between groups
affect the results of the study?
received conventional PT. The experimental group
received conventional PT and daily CPM
application for 2 hours.
88. Did the subjects know to which
treatment group they were assign?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
The patients were not blinded to group
assignments, so yes, the subjects knew which
treatment group they were assigned to. This could
cause the subjects to increase their efforts in
hopes of achieving the anticipated outcomes or
decrease their efforts as a result of frustration that
they are not in the experimental treatment group.
Therefore, it could cause changes in subject
behavior.
The therapists were not blinded to the study
groups, so yes, they knew to which treatment
group subjects were assigned. This could cause
changes in the clinician behavior. PTs assigned to
the control group may have provided added
encouragement to compensate for allocation to
the control group. Also, this could have affected
outcomes measurements, since the primary
outcome measurement was goniometric results of
active knee flexion ROM, which involves human
instrumentation.
89. Did the investigators know to which
treatment group subjects were
assigned?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
No, the investigators did not know who was being
assigned to which group prior to allocation.
Yes, the groups were similar at the start of the
trial. Both the CPM and control group had similar
initial ROM, FIM, knee girth, WOMAC, TUG, and
in their use/disuse of pre-surgical ambulation
devices. The inclusion criteria were: (1) transferred
to IRF after a single knee replacement; (2) etiology
of osteoarthritis; (3) aged 40-80 years; (4) initial
maximal knee flexion ROM between 45-75
degrees of flexion; (5) BMI <40. Exclusion criteria:
(1) revision to a previous TKR; (2) bilateral TKR;
and (3) comorbid medical conditions that could
interfere or complicate recovery.
80
90. Were the groups managed equally,
apart from the actual experimental
treatment?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
91. Was the subject follow-up time
sufficiently long to answer the
question(s) posed by the research?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
Yes, the groups were managed equally. They both
received 3 hours per day of conventional therapy
in the inpatient rehab setting, which consisted of
PT and OT. The experimental group received an
additional 2 hours per day of CPM use.
Yes, the subject follow-up time was sufficiently
long to answer the question(s) posed by the
research. The primary outcome measure was
active knee flexion ROM, and secondary outcome
measures were active knee extension ROM,
length of stay, TUG score, knee girth, total FIM
scores, ambulation device at discharge, and selfreported WOMAC score. A baseline for the
outcome measures was taken upon admission to
the inpatient rehab facility (IRF) during the PT
evaluation. The outcome measures were reassessed on the day prior to discharge by the
treating PT. Discharge date and destination were
determined by the physician-led interdisciplinary
team, who were blinded to group assignment. The
WOMAC survey was mailed to the patient’s home
1 week after discharge, and follow-up phone calls
were made to facilitate survey return.
No. During the 12-month study period, 145
patients consented and enrolled in the study. 4 of
these patients were unable to complete the study.
CPM was unavailable for use on 2 patients: one
experienced skin irritation from the pads and
another disliked the CPM. The authors just
obtained outcome data from the remaining 141
patients: 70 in the CPM group and 71 in the
control group.
92. Did all the subjects originally enrolled
complete the study?
a. If not how many subjects were
lost?
b. What, if anything, did the
authors do about this attrition?
c. What are the implications of the
attrition and the way it was
handled with respect to the
study’s findings?
93. Were all patients analyzed in the groups Yes, all patients were analyzed in the groups to
to which they were randomized (i.e. was which they were randomized.
there an intention to treat analysis)?
a. If not, what did the authors do
with the data from these
subjects?
b. If the data were excluded, what
are the potential consequences
for this study’s results?
Are the valid results of this RCT important?
Appraisal Criterion
Reader’s Comments
81
94. What were the statistical findings of this
study?
a. When appropriate use the
calculation forms below to
determine these values
b. Include: tests of differences
With p-values and CI
c. Include effect size with p-values
and CI
d. Include ARR/ABI and RRR/RBI
with p-values and CI
e. Include NNT and CI
f. Other stats should be included
here
All patients demonstrated significant
improvements in the clinical outcome measures
from admission to discharge, which included the
following: knee flexion (P<.001); knee extension
(P<.001); TUG score (P<.001); FIM score
(P>.001); and girth (P<.019). Improvement in the
patient’s perceptions of pain, stiffness, and ADL
function as measured by the WOMAC were also
significant when comparing admission scores with
the 7-day follow-up survey (P<.001).
The mean flexion AROM in the CPM group was
83°+/-10° and the control group not using CPM
was 86°+/-7.9° at discharge. These differences
were not statistically significant (F1,138=3.1, mean
square error=81.38, P<.08). The secondary
outcomes of interest were also examined at
discharge using ANCOVAs, and the results
indicated no significant effect in discharge knee
extension ROM (F1,137=1.58, P<.211), total FIM
(F1, 138=2.140, P<.146), TUG (F1, 102=0.394,
P<.532), knee girth (F1, 131=1.860, P<.175), and
WOMAC (F1, 57=1.120, P<.294), which indicates
no impact of CPM use when controlling for initial
values of each of the variables of interest. Also,
length of stay was not statistically significantly
different. An independent t test revealed both
groups stayed an average of 8 days in the IRF
(CPM mean 8.3+/-1.7 and control 8.7+/-2.7,
t139=1.01, P<.311). The combined LOS including
acute care hospitalization, during which 91% of
subjects used a CPM immediately after surgery,
also demonstrated no significant difference
between groups (CPM=12.1+/-2.3d;
control=12.6+/-3, t139=1.03, P<.306). 98% of
patients in both groups were discharged home
from the IRF, revealing no group difference.
Ambulation device use at discharge showed no
significant difference between groups. 87% of
control group and 90% of CPM group were
discharged using a single point cane for
ambulation, and a Fisher exact test showed no
statistically significant group difference (P<.792).
There was a 55% return rate of the WOMAC
survey. CPM use did not improve WOMAC scores.
Mean difference between the control group and
82
CPM group was -2.3+/-15 points, which was not
statistically or clinically significant (P<.47).
95. What is the meaning of these statistical This study found no significant benefit of CPM use
findings for your patient/client’s case?
during the post-acute rehabilitation phase
What does this mean to your practice?
compared with conventional care. However, 91%
of patients in this study did use CPMs immediately
after TKR, in the acute setting. Therefore,
according to this study my patient would not
benefit from post-acute CPM use, but may benefit
from initial CPM use, further studies need to be
examined.
96. Do these findings exceed a minimally
The average improvement on the WOMAC survey
important difference? Was this brought from admission to discharge was 17+/-17.3 points,
up or discussed?
which exceeds the minimal clinically important
a. If the MCID was not met, will
difference for TKR which is 15. However, CPM did
you still use this evidence?
not improve WOMAC scores. The mean difference
between the control group and the CPM group
was -2.3+/-1.5 points, which was not statistically or
clinically significant (P<.47).
Can you apply this valid, important evidence about an intervention in caring for your
patient/client? What is the external validity?
Appraisal Criterion
Reader’s Comments
97. Does this intervention sound
This study shows that there is no significant
appropriate for use (available,
benefit of CPM use in the inpatient rehabilitation
affordable) in your clinical setting? Do
setting. The use of CPM did not improve ROM or
you have the facilities, skill set, time, 3rd functional outcomes in the post-acute rehab phase
party coverage to provide this
compared with a control group, who received
treatment?
conventional therapy. Therefore, the use of CPMs
in the post-acute rehab phase is not improving
patient outcomes and is only raising costs and
adding unnecessary treatment time to patients in
IRF after TKR.
98. Are the study subjects similar to your
Yes, the subjects in this study were similar to my
patient/ client?
patient in diagnosis, age, and initial baseline
a. If not, how different? Can you
characteristics. The subjects were different from
use this intervention in spite of my patient because they were in the post-acute
the differences?
phase of rehabilitation and were being treated in
an IRF, whereas my patient was in the acute
phase of rehabilitation and was being treated in an
inpatient hospital.
99. Do the potential benefits outweigh the
There are no significant risks associated with CPM
potential risks using this intervention
use, other than that it is more costly to the patient.
with your patient/client?
However, this study shows that there are no
significant benefits in using the CPM with the client
in the post-acute rehab phase.
83
100.
Does the intervention fit within
your patient/client’s stated values or
expectations?
a. If not, what will you do now?
Yes, this intervention does fit within my patient’s
stated values or expectations, which are to
improve knee ROM and function.
101.
Are there any threats to external
validity in this study?
This study was performed in an IRF, where
patients receive extensive therapy. In an acute
care setting, patients do not receive the same kind
of extensive therapy that they do in an IRF. Also,
the fact that the majority of the subjects received
CPM use in the acute care setting, but the amount
of CPM use or differences between those who did
and did not receive the CPM in acute care was not
documented, could affect outcomes.
What is the bottom line?
Appraisal Criterion
PEDRO score (see scoring at end of form)
Summarize your findings and relate this back
to clinical significance
Reader’s Comments
7/10
This study showed that in patients with poor initial
ROM, CPM use offers no added benefit to
discharge ROM values when compared with
conventional PT alone. Also, CPM use did not
have any effect on improvement with the TUG test,
FIM, WOMAC, girth reduction, and LOS.
Therefore, these findings are clinically and
statistically significant in showing no difference
between functional outcomes after TKR between
groups of patients who used a CPM in post-acute
rehab, plus traditional therapy in an IRF setting,
versus patients who only received traditional
therapy in an IRF setting. Therefore, this study
shows that there is no reason to use CPM in the
post-acute rehab setting after TKR, as it does not
improve outcomes and only increases costs.
84
Intervention – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Lenssen, T. , Van Steyn, M. , Crijns, Y., Waltje, E. , Roox, G. M. , Geesink, R. , . . . De Bie, R. (2008).
Effectiveness of prolonged use of continuous passive motion (CPM), as an adjunct to
Physiotherapy, after total knee arthroplasty. BMC Musculoskeletal Disorders, 9 (60), 1471-1274.
doi: 10.1186/1471-2474-9-60
Level of Evidence (Oxford scale): 1b
Is the purpose and background information sufficient?
Appraisal Criterion
Reader’s Comments
Study Purpose
Yes, the purpose of this RCT is to investigate the
Stated clearly?
effectiveness of prolonged CPM use in the home
Usually stated briefly in abstract and in greater
situation as an adjunct to standardized PT. The
detail in introduction. May be phrased as a
effectiveness was measured in terms of faster
question or hypothesis.
improvements in ROM and functional recovery.
A clear statement helps you determine if topic is
The authors’ primary goal was to establish whether
important, relevant and of interest to you. Consider there is additional longer-term benefit of continuing
how the study can be applied to PT and/or your
CPM after hospital discharge.
own situation. What is the purpose of this study?
Literature
Relevant background presented?
A review of the literature should provide
background for the study by synthesizing relevant
information such as previous research and gaps in
current knowledge, along with the clinical
importance of the topic.
Describe the justification of the need for this study
Research suggests that CPM should be
implemented in the first rehab phase after surgery,
but there is debate about the duration of each
CPM session and the total period of CPM
application. A Cochrane review concluded that
short-term use of CPM leads to greater short-term
ROM. However, it also suggested that future
research should concentrate on the treatment
period during which CPM should be administered.
Does the research design have strong internal validity?
Appraisal Criterion
Reader’s Comments
Assignment, attrition, history, maturation,
 Discuss possible threats to internal
compensatory equalization of treatments, and
validity in the research design. Include: statistical regression should not have posed
 Assignment
threats to internal validity. However,
 Attrition
instrumentation could have posed a threat to
 History
internal validity because the primary outcome was
 Instrumentation
flexion ROM, which was measured with a
85
 Maturation
 Testing
 Compensatory Equalization of
treatments
 Compensatory rivalry
 Statistical Regression
Are the results of this therapeutic trial valid?
Appraisal Criterion
102.
Did the investigators randomly
assign subjects to treatment groups?
a. If no, describe what was done
b. What are the potential
consequences of this
assignment process for the
study’s results?
103.
Did the investigators know who
was being assigned to which group
prior to the allocation?
a. If they were not blind, what are
the potential consequences of
this knowledge for the study’s
results?
104.
Were the groups similar at the
start of the trial? Did they report the
demographics of the study groups?
a. If they were not similar – what
differences existed?
b. Do you consider these
differences a threat to the
research validity? How might
the differences between groups
affect the results of the study?
105.
Did the subjects know to which
treatment group they were assign?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
106.
Did the investigators know to
which treatment group subjects were
assigned?
a. If yes, what are the potential
consequences of the subjects’
goniometer. Compensatory rivalry could have
posed a threat because the pts did know which
group they were assigned to, and several of the
secondary outcome measures were subjective.
Reader’s Comments
Yes, 60 pts with knee OA, undergoing TKA and
experiencing early postoperative flexion
impairment were randomized over 2 treatment
groups. Blocked and concealed randomization
with a block size of four ensured equal distribution
of pts over the 2 treatment groups.
No, the investigators did not know who was being
assigned to which group prior to the allocation.
The groups were similar at the start of the trial,
and demographics were reported in a table
included in the study.
Yes, the subjects knew to which treatment group
they were assigned. It is difficult to blind patients
due to the nature of the CPM.
The outcome assessors were blinded to the
treatment procedures. Therefore, they did not
know if the patients they assessed belonged to the
CPM or no-CPM group.
86
knowledge for this study’s
results
107.
Were the groups managed
equally, apart from the actual
experimental treatment?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
108.
Was the subject follow-up time
sufficiently long to answer the
question(s) posed by the research?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
109.
Did all the subjects originally
enrolled complete the study?
a. If not how many subjects were
lost?
b. What, if anything, did the
authors do about this attrition?
c. What are the implications of the
attrition and the way it was
handled with respect to the
study’s findings?
110.
Were all patients analyzed in the
groups to which they were randomized
(i.e. was there an intention to treat
analysis)?
During their stay in the hospital, all pts received a
standardized PT treatment, involving 20 minutes
of PT and 4 hours of CPM use daily for 4 days.
CPM was initially applied in the recovery room and
was then used for 2 consecutive hours, twice
daily. ROM was set to pt tolerance. After d/c, all
pts were randomly assigned to one of the following
groups: a control group which received semistandardized regular PT and an experimental
group which received the same PT intervention in
combination with 2 extra weeks of CPM treatment
for 4 hours daily. Patients were able to increase
CPM ROM by themselves, and they kept a pt log
where they wrote the parameters of their CPM and
PT treatments, medication use and pain. Patients
received regular PT treatment from day 18
onward, until pts and PT were satisfied with their
functioning. The post-acute PT was standardized
in terms of treatment objectives, but all pts
received active and passive mobilization of knee,
active strengthening of quadriceps, and ADL
training. The mean duration of the treatment
sessions was 30 minutes.
Outcome measures were assessed at 17 days, 6
weeks and 3 months after surgery,
Yes, all subjects originally enrolled completed the
study. However, one subject in the experimental
group reduced CPM use to 2 hours from day 10
onwards, because her knee ROM was over 105
degrees, and she felt uncomfortable with 4 hours
of CPM use when reaching high degrees of
flexion. Also, one subject in each group had to
undergo knee manipulation under anesthesia
between six weeks and 3 months after surgery.
Yes, all patients were analyzed in the groups to
which they were randomized.
87
a. If not, what did the authors do
with the data from these
subjects?
b. If the data were excluded, what
are the potential consequences
for this study’s results?
Are the valid results of this RCT important?
Appraisal Criterion
111.
What were the statistical
findings of this study?
a. When appropriate use the
calculation forms below to
determine these values
b. Include: tests of differences
With p-values and CI
c. Include effect size with p-values
and CI
d. Include ARR/ABI and RRR/RBI
with p-values and CI
e. Include NNT and CI
f. Other stats should be included
here
Reader’s Comments
A trend in favor of prolonged CPM use was found
at the end of the treatment period. In terms of total
ROM, the CPM group achieved 5 degrees more
ROM than the PT group. ROM in the CPM group
improved 6 degrees more during the active
treatment period. However, at follow-up, these
differences had faded; there was no significant
differences between the two groups at 6 weeks
and 3 months. The experimental group scored
slightly better on the KSS functional status score
and WOMAC functional difficulty score, no
significant differences were found between the 2
groups, neither at day 17 nor at either of the
follow-up measurements. No significant
differences were found on any of the secondary
outcome measures at any single outcome
measurement.
112.
What is the meaning of these
This means that although CPM use may have
statistical findings for your
positive effects on short-term ROM, these benefits
patient/client’s case? What does this
do not carry over. Therefore, there is no lasting
mean to your practice?
benefit to CPM post-acutely. Therefore, pts should
not be sent home with a CPM.
113.
Do these findings exceed a
The study states that there was no difference in
minimally important difference? Was
the numbers of patients achieving the clinically
this brought up or discussed?
important benchmarks of 95 and 105 degrees of
a. If the MCID was not met, will
flexion, at the end of the treatment period nor at
you still use this evidence?
follow-up. Therefore it is doubtful whether the
additional degrees of ROM are of clinical
importance.
Can you apply this valid, important evidence about an intervention in caring for your
patient/client? What is the external validity?
Appraisal Criterion
Reader’s Comments
114.
Does this intervention sound
Yes, the intervention sounds appropriate for use in
appropriate for use (available,
the acute care setting. However, this study looks
affordable) in your clinical setting? Do
at the use of CPM in the home environment. This
you have the facilities, skill set, time, 3rd treatment needs to be more carefully examined,
party coverage to provide this
as this study did not show any long-term benefit;
treatment?
therefore, if there is no benefit, costs could be cut
88
and better therapy could be provided to pts by not
providing them with a home CPM.
115.
Are the study subjects similar to Yes, the subjects were similar to my patient
your patient/ client?
because they had knee OA, had undergone TKA,
a. If not, how different? Can you
and were experiencing early postoperative flexion
use this intervention in spite of
impairment. The difference is that these pts had
the differences?
undergone tx in the acute care setting and the
experimental group was then sent home with a
CPM. My patient was treated in the acute care
environment and not sent home with a CPM.
116.
Do the potential benefits
Yes, I believe the potential benefits of using a
outweigh the potential risks using this
CPM machine, especially with a client like mine,
intervention with your patient/client?
who has extremely limited ROM outweigh the
potential risks because the CPM protocol is not
risky or harmful.
117.
Does the intervention fit within
Yes, the intervention fits within my patient’s values
your patient/client’s stated values or
to increase her ROM and functional outcomes.
expectations?
a. If not, what will you do now?
118.
Are there any threats to external
validity in this study?
What is the bottom line?
Appraisal Criterion
PEDRO score (see scoring at end of form)
Summarize your findings and relate this back
to clinical significance
The fact that the authors chose to include pts with
limited ROM at the end of the in-hospital period
Reader’s Comments
8/10
This study demonstrated improvement in total
ROM at the end of the prolonged period of CPM
use. However, this did not translate into functional
benefits. Therefore, although CPM produces
benefits in knee ROM in the short term, it does not
result in additional ROM in the long term, nor in
functional gain. The results of this study indicate
that prolonged CPM use has a short-term effect on
ROM. However, implementation of prolonged CPM
use at hospital d/c should be reconsidered, since
neither long-term effects nor transfer to better
functional outcomes have been detected.
89
Intervention – Evidence Appraisal Worksheet
Citation (use AMA or APA format):
Maniar, R. N., Baviskar, J. V., Singhi, T., & Rathi, S. S. (2012). To use or not to use continuous passive
Motion post-total knee arthroplasty. The Journal of Arthroplasty 27 (2), 193-201. doi:
10.1016/j.arth.2011.04.009
Level of Evidence (Oxford scale): 1b
Is the purpose and background information sufficient?
Appraisal Criterion
Reader’s Comments
Study Purpose
Yes, the purpose to this study is to evaluate in a
Stated clearly?
prospective, randomized manner the effect of
Usually stated briefly in abstract and in greater
using CPM by assessing specific parameters. The
detail in introduction. May be phrased as a
TUG test was used to evaluate the functional
question or hypothesis.
outcome of using a CPM. This study also
A clear statement helps you determine if topic is
hypothesizes that CPM may be useful in initializing
important, relevant and of interest to you. Consider knee flexion so that further active and passive
how the study can be applied to PT and/or your
motion training becomes easier and better
own situation. What is the purpose of this study?
tolerated. Therefore, a 1-day CPM application
group was formed. This group received CPM only
for the 1 day when knee ROM exercises were
initiated.
Literature
Relevant background presented?
A review of the literature should provide
background for the study by synthesizing relevant
information such as previous research and gaps in
current knowledge, along with the clinical
importance of the topic.
Describe the justification of the need for this study
Yes, relevant background is presented. The
benefits of CPM use are controversial. Most
studies have shown no long term benefit of CPM
use. Also, earlier studies have evaluated the
benefits of CPM use based on outcome measures
of ROM, length of stay, volume of drain, pain, and
functional and knee scores like the WOMAC,
Osteoarthritis Index, and SF-36. This study argues
that besides ROM these other parameters are not
indicative of function. Therefore, this study is
unique because it includes the TUG test. Also,
previous studies have varied in their frequency and
duration of CPM use and some have used different
protocols for the CPM vs non-CPM groups. This
study has maintained the same protocol for the
groups with the only variant being the use of CPM
and the duration of its use.
Does the research design have strong internal validity?
90
Appraisal Criterion
 Discuss possible threats to internal
validity in the research design. Include:
 Assignment
 Attrition
 History
 Instrumentation
 Maturation
 Testing
 Compensatory Equalization of
treatments
 Compensatory rivalry
 Statistical Regression
Are the results of this therapeutic trial valid?
Appraisal Criterion
119.
Did the investigators randomly
assign subjects to treatment groups?
a. If no, describe what was done
b. What are the potential
consequences of this
assignment process for the
study’s results?
120.
Did the investigators know who
was being assigned to which group
prior to the allocation?
a. If they were not blind, what are
the potential consequences of
this knowledge for the study’s
results?
Reader’s Comments
All subjects were randomly assigned after surgery,
using sealed envelopes to 1 of 3 groups: 1) control
group, which received conventional PT only; 2) 1day-CPM, who received conventional PT and 2
CPM applications of 15 mins each on day 2 after
TKA; 3) 3-day-CPM group, which received
conventional PT and 2 CPM applications of 15
mins each daily for 3 days (days 2, 3, & 4 after
TKA). Since groups were randomly assigned, this
should not be a threat to internal validity.
Instrumentation could be a threat to internal
validity because ROM was an outcome measure,
and goniometry is not always a reliable measure,
so this could be a threat to internal validity. Also
suprapatellar and calf girths could threaten internal
validity because these measurements are not
always reliable. Maturation should not be a threat
because outcomes were only measured for 5 days
after surgery. Statistical regression should not be
an issue because there were not many initially
extreme measurements. Compensatory rivalry
could have been an issue because the participants
knew which group they belonged to.
Reader’s Comments
Yes, they did. All subjects were randomly
assigned after surgery, using sealed envelopes to
1 of 3 groups: 1) control group, which received
conventional PT only; 2) 1-day-CPM, who
received conventional PT and 2 CPM applications
of 15 mins each on day 2 after TKA; 3) 3-day-CPM
group, which received conventional PT and 2 CPM
applications of 15 mins each daily for 3 days (days
2, 3, & 4 after TKA).
No, they did not. There was concealed allocation.
91
121.
Were the groups similar at the
start of the trial? Did they report the
demographics of the study groups?
a. If they were not similar – what
differences existed?
b. Do you consider these
differences a threat to the
research validity? How might
the differences between groups
affect the results of the study?
122.
Did the subjects know to which
treatment group they were assign?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
123.
Did the investigators know to
which treatment group subjects were
assigned ?
a. If yes, what are the potential
consequences of the subjects’
knowledge for this study’s
results
124.
Were the groups managed
equally, apart from the actual
experimental treatment?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
125.
Was the subject follow-up time
sufficiently long to answer the
question(s) posed by the research?
a. If not, what are the potential
consequences of this
knowledge for the study’s
results?
126.
Did all the subjects originally
enrolled complete the study?
a. If not how many subjects were
lost?
b. What, if anything, did the
authors do about this attrition?
c. What are the implications of the
attrition and the way it was
Yes, the groups were similar in all demographics
at the start of the trial. There were no significant
differences between them. A chart is included
showing these results.
Yes, the subjects knew to which group they were
assigned. It was written in their concealed
envelope. This could have decreased internal
validity, by leading to compensatory rivalry.
This study does not specifically state whether
investigators knew to which treatment group
subjects were assigned, but I would assume they
did, due to the nature of the CPM machine.
Therefore, this could have decreased internal
validity and lead to compensatory equalization or
measurement errors.
Yes, all the groups performed the same PT
protocol. The 2 CPM groups also received the
CPM treatment.
Yes, because this study is examining the short
term benefits of using a CPM machine, the follow
up time of 3 months is sufficiently long to answer
the questions posed by this research.
During the 3 months of this study, 90 patients
underwent primary TKA. 6 of these patients did
not conform to the study’s selection criteria-2 had
Parkinsonism, 2 had RA but were non-ambulatory
preoperatively, and 2 were from another country
and unavailable for follow up. Therefore, 84
patients completed the study and were spread in 3
groups of 28 patients. Each of the groups had 23
unilateral TKAs and 5 bilateral TKAs. Therefore,
92
handled with respect to the
study’s findings?
127.
Were all patients analyzed in the
groups to which they were randomized
(i.e. was there an intention to treat
analysis)?
a. If not, what did the authors do
with the data from these
subjects?
b. If the data were excluded, what
are the potential consequences
for this study’s results?
Are the valid results of this RCT important?
Appraisal Criterion
128.
What were the statistical
findings of this study?
a. When appropriate use the
calculation forms below to
determine these values
b. Include: tests of differences
With p-values and CI
c. Include effect size with p-values
and CI
d. Include ARR/ABI and RRR/RBI
with p-values and CI
e. Include NNT and CI
f. Other stats should be included
here
the results from the patients who were not eligible
or did not complete the study were not included in
the study’s findings and all the groups were the
same size with similar demographics, so this
should not affect the findings.
Yes, all patients were analyzed in the groups to
which they were randomized.
Reader’s Comments
Pain at rest on the VAS showed no statistically
significant differences between the 3 groups at all
time intervals, p>.05. However, at day 5, 1-dayCPM group patients scored less pain on the VAS,
with a p value=.0669, which is nearing
significance. This may indicate that initialization of
knee bending with CPM might lead to better pain
relief and exercise tolerance in the initial
postoperative period. However, further studies
need to be done. ROM was the was also not
statistically significantly different among the 3
groups, with all three averaging similar ROM on
the same time intervals. It was found that ROM in
each group returned to preoperative value of 110
degrees, by day 42. For the TUG, all 3 groups
showed a statistically significant improvement at
post-op day 90, compared to pre-operative values,
but the values were not statistically significantly
different among the groups. Therefore, the authors
conclude from this that CPM application whether
for 1 or 3 days does not have any influence in the
early functional recovery post-primary TKA.
WOMAC and SF-12 scores were comparable in
the 3 groups pre-operatively. However, they were
again scored at days 42 and 90, but not all
patients could carry out all the activities required
for these scores at da 42, making them
inappropriate for comparison. At 90 days, there
was significant improvement in both these scores
93
129.
What is the meaning of these
statistical findings for your
patient/client’s case? What does this
mean to your practice?
within individual groups, as compared to
preoperative values. However, there was no
statistical significant difference between the 3
groups. Wound staining was higher in both CPM
groups compared to the control. Although, it was
not statistically significant. Also, suprapatellar girth
took much longer to reduce to the preoperative
status in both CPM groups compared to the
control. In the 2 CPM groups, a statistically
significant swelling persisted at day 42 (p=.009 in
1-day-CPM group and p<.001 in 3-day CPM
group). At day 90, the swelling in both CPM
groups returned to within no significant difference
of preoperative values.
These findings suggest that CPM use does not
influence the early functional recovery post TKA.
Therefore, this study suggests that my patient will
not benefit, in the short-term, from use of a CPM in
the acute care setting. Therefore, to give her one
would only be a waste of time and resources for
no additional benefit.
This was not discussed in this study.
130.
Do these findings exceed a
minimally important difference? Was
this brought up or discussed?
a. If the MCID was not met, will
you still use this evidence?
Can you apply this valid, important evidence about an intervention in caring for your
patient/client? What is the external validity?
Appraisal Criterion
Reader’s Comments
131.
Does this intervention sound
Yes, the PT protocol is appropriate for use in my
appropriate for use (available,
clinical setting. The CPM protocol also is.
affordable) in your clinical setting? Do
However, further studies need to be done to make
you have the facilities, skill set, time, 3rd sure that it does not benefit patients before time
party coverage to provide this
and money is wasted on CPM use and set-up.
treatment?
132.
Are the study subjects similar to Yes, these subjects were similar in that they had a
your patient/ client?
pre-operative diagnosis of knee OA or RA, were
a. If not, how different? Can you
expecting a TKA, and were ambulatory and able to
use this intervention in spite of
walk a distance of 3m and back.
the differences?
133.
Do the potential benefits
CPM use is not a risky procedure. Therefore, more
outweigh the potential risks using this
studies need to be conducted to determine if
intervention with your patient/client?
indeed it does not benefit patients to use the CPM.
134.
Does the intervention fit within
Yes, PT alone and PT plus the use of a CPM fit
your patient/client’s stated values or
within my patient’s stated values and expectations,
expectations?
94
a. If not, what will you do now?
135.
Are there any threats to external
validity in this study?
What is the bottom line?
Appraisal Criterion
PEDRO score (see scoring at end of form)
Summarize your findings and relate this back
to clinical significance
which are to improve ROM and functional outcome
post-TKA.
No, I did not identify any threats to external validity
in this study.
Reader’s Comments
7/10
The outcome measurements in this study showed
no statistically significant difference among the 3
groups in each parameter, pre-operatively and
postoperatively on days 3, 5, 14, 42, and 90.
Therefore, this study concluded that CPM offers no
benefit in immediate functional recovery post-TKA,
and found that postoperative knee swelling actually
lasted longer. No significant beneficial role of CPM
in the immediate functional recovery after TKA was
found, including no improvement in ROM or
functional outcomes like TUG. However, there was
an indication of better pain relief with just 1 day of
CPM application. However, wound staining was
higher and postoperative supra-patellar swelling
took longer to reduce in patients in the CPM
groups, even though this was not shown to be
statistically significant. Therefore, the indications of
using a CPM according to this study would be for 1
day to reduce pain. Otherwise, CPM use does not
improve ROM or functional outcomes in the shortterm, as compared to traditional PT.