The American Journal of Sports
Medicine
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Loss of Normal Knee Motion After Anterior Cruciate Ligament Reconstruction Is Associated With
Radiographic Arthritic Changes After Surgery
K. Donald Shelbourne, Scott E. Urch, Tinker Gray and Heather Freeman
Am J Sports Med 2012 40: 108 originally published online October 11, 2011
DOI: 10.1177/0363546511423639
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Loss of Normal Knee Motion After
Anterior Cruciate Ligament Reconstruction
Is Associated With Radiographic
Arthritic Changes After Surgery
K. Donald Shelbourne,*y MD, Scott E. Urch,y MD,
Tinker Gray,y MA, and Heather Freeman,y PT, DHS
Investigation performed at Shelbourne Knee Center, Indianapolis, Indiana
Background: Meniscectomy and articular cartilage damage have been found to increase the prevalence of osteoarthritis after
anterior cruciate ligament reconstruction, but the effect of knee range of motion has not been extensively studied.
Hypothesis: The prevalence of osteoarthritis as observed on radiographs would be higher in patients who had abnormal knee range
of motion compared with patients with normal knee motion, even when grouped for like meniscal or articular cartilage lesions.
Study Design: Cohort study; Level of evidence, 3.
Methods: We prospectively followed patients at a minimum of 5 years after surgery. The constant goal of rehabilitation was to
obtain full knee range of motion as quickly as possible after surgery and maintain it in the long term. Range of motion and radiographs were evaluated at the time of initial return to full activities (early follow-up) and final follow-up according to International
Knee Documentation Committee (IKDC) objective criteria. A patient was considered to have normal range of motion if extension
was within 2° of the opposite knee including hyperextension and knee flexion was within 5°. Radiograph findings were rated as
abnormal if any signs of joint space narrowing, sclerosis, or osteophytes were present.
Results: Follow-up was obtained for 780 patients at a mean of 10.5 6 4.2 years after surgery. Of these, 539 had either normal or
abnormal motion at both early and final follow-up. In 479 patients who had normal extension and flexion at both early and final
follow-up, 188 (39%) had radiographic evidence of osteoarthritis versus 32 of 60 (53%) patients who had less than normal extension
or flexion at early and final follow-up (P = .036). In subgroups of patients with like meniscal status, the prevalence of normal radiograph
findings was significantly higher in patients with normal motion at final follow-up versus patients with motion deficits. Multivariate logistic regression analysis of categorical variables showed that abnormal knee flexion at early follow-up, abnormal knee extension at final
follow-up, abnormal knee flexion at final follow-up, partial medial meniscectomy, and articular cartilage damage were significant factors
related to the presence of osteoarthritis on radiographs. Abnormal knee extension at early follow-up showed a trend toward statistical
significance (P = .0544). Logistic regression showed the odds of having osteoarthritis were 2 times more for patients with abnormal
range of motion at final follow-up; these odds were similar for those with partial medial meniscectomy and articular cartilage damage.
Conclusion: The prevalence of osteoarthritis on radiographs in the long term after anterior cruciate ligament reconstruction is
lower in patients who achieve and maintain normal knee motion, regardless of the status of the meniscus.
Keywords: anterior cruciate ligament; range of motion; meniscus; radiographs; long-term results
tomy and articular cartilage damage.z A few studies
have examined the association between loss of knee
range of motion (ROM) and arthritic changes on radiographs. Roe et al21 stated that flexion contractures
were associated with early osteoarthritic changes at
a mean of 7 years after ACL reconstruction. Salmon
et al23 found that loss of knee extension at 13 years after
surgery and lateral or medial meniscectomy at the time
of ACL reconstruction were related to a higher incidence
of OA at follow-up. In a minimum 10-year follow-up
study of 502 patients, Shelbourne and Gray27 found
that patients who had less than normal ROM were about
Several studies have established that major risk factors
for the development of osteoarthritis (OA) after anterior
cruciate ligament (ACL) reconstruction are meniscec*Address correspondence to K. Donald Shelbourne, MD, Shelbourne
Knee Center, 1815 North Capitol Avenue, Indianapolis, IN 46202 (e-mail:
tgray@aclmd.com).
y
Shelbourne Knee Center, Indianapolis, Indiana.
Presented at the 37th annual meeting of the AOSSM, San Diego, California, July 2011.
The authors declared that they have no conflicts of interest in the
authorship and publication of this contribution.
The American Journal of Sports Medicine, Vol. 40, No. 1
DOI: 10.1177/0363546511423639
Ó 2012 The Author(s)
z
References 1, 5-8, 10, 13, 15, 17, 20, 21, 23, 25, 27, 28.
108
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Vol. 40, No. 1, 2012
ROM Loss and OA After ACL Reconstruction
2.5 times as likely to have abnormal radiograph findings
as patients with normal ROM.
Rehabilitation programs with ACL reconstruction have
evolved through the years from restricting ROM after surgery for a determined amount of time to more current
times when unrestricted ROM immediately after surgery
is allowed and encouraged. Regardless of the rehabilitation
plan for achieving full knee ROM, deficits in ROM compared with the opposite knee still exist in many patients
after ACL reconstruction.
The purpose of this study was to determine how knee
ROM deficits would correlate with the prevalence of
arthritic changes observed on radiographs after ACL
reconstruction. We hypothesized that the prevalence of
OA as observed on radiographs would be higher in a group
of patients who had loss of normal knee ROM than in
patients with normal knee ROM, even when grouped for
like meniscal or articular cartilage abnormality.
109
Figure 1 To measure knee hyperextension, the heel of the
foot is placed on a bolster so the knee can fall into hyperextension, if it is present. Knee range of motion is measured
with a goniometer.
MATERIALS AND METHODS
Between 1987 and 2004, 3243 patients were prospectively
enrolled in a long-term outcome study after ACL reconstruction with an autogenous patellar tendon graft. All
patients gave informed consent to participate in the study,
and the study was approved by the institutional review
board. Patients were evaluated at regular intervals after
surgery to include 2, 5, 10, and 20 years after surgery.
Patients were excluded from this analysis if they had bilateral ACL injuries (n = 749), had arthritic changes on radiographs before surgery (n = 419), were deceased (n = 91), or
had a subsequent ACL graft tear after surgery (n = 175). Of
1809 patients who met the criteria for the study, 780
patients had a minimum of 5 years of objective and subjective follow-up after surgery and are the focus of this study.
At the time of surgery, an arthroscopic procedure was
performed to evaluate and treat, if needed, any meniscal
injuries or articular cartilage damage. The articular cartilage was graded for the femur and tibia in the medial and
lateral compartments and for the patella according to the
Outerbridge scale.19 Rehabilitation after surgery emphasized obtaining full knee ROM as soon as possible after surgery, and this program has been described previously.26,30
Knee ROM was evaluated with the patient lying supine
and was measured with a goniometer as described by Norkin and White.16 The patient’s heel was elevated on a bolster to allow the knee to go into hyperextension if present
(Figure 1). Knee flexion was measured by having the
patient bend the knee to slide the heel toward the buttocks
as far as possible.
According to International Knee Documentation Committee (IKDC) criteria, normal knee extension is considered within 2° of the opposite normal knee, and normal
flexion is considered to be within 5° of the opposite normal
knee. Although IKDC criteria use 4 grades of normal,
nearly normal, abnormal, and severely abnormal, we categorized knee extension and flexion as ‘‘abnormal’’ for any
grade less than normal. Patients were also assigned an
IKDC overall ROM rating, in which normal ROM was
defined as the patient having both normal extension and
flexion; abnormal was defined as the patient having less
than normal extension or flexion.
For this study, IKDC categories for ROM were evaluated at 2 time frames. The first time was when the patient
was released to return to activities (early follow-up), and
this time varied between patients depending on when
they reached their rehabilitation goals. The mean time of
this observation was 6.2 6 2.1 months after surgery. The
second time when ROM data were evaluated was at the
latest follow-up visit at greater than 5 years after surgery
(final follow-up).
Ligament stability was evaluated with a KT-1000
arthrometer, and the manual maximum difference
between knees was measured. Radiographs obtained
included bilateral knee views to include a 45° posteroanterior weightbearing view,22 Merchant view,14 and lateral
view. Radiographs were graded according to criteria
described by the IKDC.2 A grade of normal (A) means
that there was no evidence of arthritic changes in the joint.
A grade of nearly normal (B) indicates the presence of
small osteophytes, slight sclerosis, flattening of the femoral
condyles, and/or narrowing of the joint space that is just
detectable. A grade of abnormal (C) indicates similar
arthritic changes but also includes joint space narrowing
up to 50% of the joint space. A grade of severely abnormal
(D) indicated arthritic changes and includes joint space
narrowing greater than 50%. Although the specific IKDC
radiographic grade was recorded at the time of evaluation,
we used only 2 categories of normal or abnormal in our
analysis. If the knee was graded less than ‘‘A’’ in any compartment, it received a grade of abnormal for this analysis.
Data Analysis
Descriptive statistics were obtained. Multivariate logistic
regression was performed on categorical variables, and
univariate logistic regression was performed on continuous
variables to determine their relationship to the presence of
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110
Shelbourne et al
The American Journal of Sports Medicine
TABLE 1
Multivariate Logistic Regression Analysis of Categorical Variables Related to Radiographic Osteoarthritis at Follow-up
Variable
Early extension, abnormala
Early flexion, abnormala
Final follow-up extension, abnormal
Final follow-up flexion, abnormal
Medial meniscus removed
Lateral meniscus removed
Articular cartilage, abnormal
Coefficient
Standard Error
P Value
Odds Ratio
95% Confidence Interval
.1077
.4616
.4913
.6268
.6339
.1858
.7423
.1513
.1788
.2246
.1796
.1472
.1768
.1722
.0544
.0098
.0287
.041
.0012
.294
\.01
1.1
1.6
1.9
1.8
1.8
1.1
2.1
0.83-1.5
1.1-2.3
1.3-2.9
1.3-2.6
1.4-2.5
0.85-1.7
1.5-2.9
a
Early follow-up time when the patient was released to return to full activities.
OA on radiographs at final follow-up. The x2 test was used
to determine whether there was a statistically significant
difference in the number of patients who had abnormal
radiographic ratings based on whether they had an IKDC
overall ROM rating of abnormal or normal ROM at both
follow-up times.
Further subanalysis was performed based on the status
of the medial and lateral meniscus at the time of surgery or
at the time of a subsequent arthroscopic procedure after
ACL reconstruction, with the 4 categories being both
menisci intact, partial medial meniscectomy, partial lateral meniscectomy, or partial medial and lateral meniscectomy. Subanalysis based on the status of the articular
cartilage was performed by using 2 categories of normal
(grade 2 or less in all compartments) or abnormal (grade
3 or 4 in any compartment). Statistical significance was
set at P \ .05. The data were analyzed using Base SAS,
SAS Access, and SAS Stat statistical software (SAS Institute, Cary, North Carolina).
RESULTS
The mean age for patients at the time of surgery was 25.4 6
9.2 years. The mean time for latest follow-up evaluation was
10.5 6 4.5 years (range, 5-21.2 years). The mean KT-1000
arthrometer manual maximum difference between knees
was 1.9 6 1.3 mm, with 91% of patients with 3 mm, 8%
with 4 to 5 mm, and 1% with .5 mm.
At final follow-up, the IKDC rating for knee extension
was ‘‘A’’ for 89% of patients, ‘‘B’’ for 10%, and ‘‘C’’ for 1%.
The IKDC rating for knee flexion was ‘‘A’’ for 79% of
patients, ‘‘B’’ for 16%, ‘‘C’’ for 3%, and ‘‘D’’ for 2%. The percentage of patients who had both normal knee extension
and flexion was 68% at final follow-up. Ninety-two percent
of patients had some degree of hyperextension (range, 1°14°), with the average being 5°. Thirty-three patients
(4.2%) did not obtain at least 0° (neutral) knee extension.
The IKDC category for overall ROM remained the same
for 69% of patients from early follow-up to final follow-up
(479 remained as normal, and 60 remained as abnormal).
The overall IKDC ROM category changed from normal to
abnormal in 13% (102 patients) and from abnormal to normal in 18% (139 patients). In 479 patients who had both
normal extension and flexion from early to final follow-up,
188 (39%) had radiographic evidence of OA versus 32 of
60 (53%) patients who had less than normal extension or
flexion throughout follow-up (P = .036).
Multivariate logistic regression analysis of categorical
variables showed that abnormal knee flexion at early
follow-up, abnormal knee extension at final follow-up,
abnormal knee flexion at final follow-up, partial medial
meniscectomy, and articular cartilage damage were significant factors correlating with the presence of OA on
radiographs (Table 1). Abnormal knee extension at early
follow-up showed a trend toward statistical significance
(P = .0544). The multivariate logistic regression analysis
showed that ROM loss at final follow-up, partial medial
meniscectomy, and articular cartilage damage each had
about 2 times the odds of having OA. Univariate logistic
regression analysis showed that older age at time of surgery
(P \ .1) and longer follow-up time (P \ .01) were statistically significant factors correlating with OA on radiographs.
In patients who had both menisci intact, the radiograph
results were rated as normal in all joint compartments in
88% of patients versus 63% in patients who had both
a medial and lateral meniscectomy (see the Appendix,
available in the online version of this article at http://
ajs.sagepub.com/supplemental/). The percentage of
patients with normal radiograph results was 69% in
patients with normal knee extension at final follow-up
and 70% in patients with normal knee flexion at final
follow-up, which was statistically significantly higher
than patients who had abnormal extension or flexion at
final follow-up (P \ .001) (Figure 2). Overall, the percentage of patients who had normal radiograph results was
71% in patients with both normal extension and flexion
(normal ROM) at final follow-up and 55% for patients
who had any deficit in ROM at final follow-up (P \ .001).
The percentage of patients who had normal radiograph
results was statistically significantly higher for patients
with normal ROM at final follow-up within each meniscus
tear group (Figure 3).
In the group of patients with normal articular cartilage
at the time of surgery (n = 611), normal radiograph findings were found for 328 of 427 (77%) patients with normal
ROM at final follow-up versus 114 of 184 (62%) patients
with abnormal ROM (P \ .001). In patients with abnormal
articular cartilage at the time of surgery (n = 169), normal
radiograph results were found for 48 of 100 (48%) patients
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Vol. 40, No. 1, 2012
100
90
80
70
60
50
40
30
20
10
0
%
ROM Loss and OA After ACL Reconstruction
Extension
69
Flexion
70
57
50
50
43
42
Normal
Nearly Normal
Abnormal Severely Abnormal
Extension and Flexion Rating
Figure 2 The number of patients with no evidence of osteoarthritis (normal radiographic rating) was statistically significantly higher in patients with normal extension and normal
flexion versus those with less than normal range of motion
ratings. (There were no patients who had a knee extension
rating of severely abnormal.)
100
90
80
70
60
50
40
30
20
10
0
%
Normal ROM*
77
74
67
Abnormal ROM*
56
56
41
38
24
Intact
Medial
Meniscectomy
Lateral
Medial and Lateral
Meniscectomy Meniscectomy
Meniscus Group
Figure 3 There was a statistically significant difference in the
number of patients with normal radiograph findings versus
abnormal radiograph findings within each meniscus group:
intact menisci (P = .01), medial meniscectomy (P = .035), lateral meniscectomy (P \ .01), and both medial and lateral
meniscectomy (P = .021). ROM, range of motion.
if they had normal ROM at final follow-up versus 25 of 69
(36%) patients with abnormal ROM (P = .12).
DISCUSSION
The results of this study showed that, when the factors of
the meniscus status or articular cartilage damage are equalized, loss of normal knee ROM at final follow-up was associated with a higher prevalence of OA on radiographs in the
long term. In patients with partial meniscectomy and/or
articular cartilage damage, the loss of ROM was associated
with a further increase in prevalence of OA. Furthermore,
patients with loss of knee ROM of .5° of extension or
.15° of flexion at final follow-up (IKDC ROM rating of
abnormal or severely abnormal) had the highest prevalence
of radiographic evidence of OA, as illustrated in Figure 2.
The radiographic rating scale used in this study was the
IKDC criteria. The IKDC scale is similar to the Kellgren
111
and Lawrence (K&L) classification system for grading
radiographs.9 The IKDC classification of ‘‘B’’ is similar to
K&L grade 2. The IKDC grade ‘‘C’’ is similar to K&L grade
3, and IKDC grade ‘‘D’’ is similar to K&L grade 4. Of studies evaluating posteroanterior weightbearing radiographs
at 5 years or more after surgery and using the criteria
for OA as either the IKDC radiographic grade of B, C, or
D or the K&L grade of 2 or higher, the prevalence of OA
in the long term after ACL reconstruction ranges from
18% to 80%.§ The major factors found to be related to
a higher prevalence of OA in these studies were meniscectomy, time from injury to surgery, and articular cartilage
damage. The wide range for the prevalence of radiographic
OA between studies could be because of different follow-up
times, the patients’ ages at the time of surgery, and the
number of patients who underwent meniscectomy or who
had existing OA before undergoing ACL reconstruction.
The results of our study show that having a ROM deficit
is a major factor associated with a higher prevalence of OA
after ACL reconstruction. However, knee ROM in other
studies is not always consistently evaluated or reported
with regard to whether the measurement is compared to
the noninvolved knee or whether knee hyperextension is
included in the evaluation. Unless investigators specifically
state how the patient was positioned and how ROM was
measured, it is unknown whether knee hyperextension
was included in the comparison between knees. Subtle differences for critically measuring passive knee hyperextension can be observed when the heels are placed on
a bolster with the patient lying supine on the examination
table. Another technique for observing differences in knee
hyperextension is looking for heel height differences with
the patient lying prone with his or her lower legs off the
end of the examination table.24 However, patients with
extension deficits are typically more uncomfortable in this
position, and it is common for them to tilt their pelvis, which
can affect the measurement. Another way to feel a difference
in extension kinesthetically is to passively extend the
patient’s knee by holding the thigh in place with one hand
and using the other hand to hold the ball of the foot to lift
the heel off the examination table (Figure 4).
The average degree of hyperextension in normal knees
is 6° in women and 5° in men, and 95% of people have
some degree of hyperextension in their knees.4 The results
in our study showed that 92% of patients had some degree
of hyperextension, with the average being 5°. If passive
hyperextension is not included as part of a regular physical
examination, the subtle difference of 3° to 5° between
knees (IKDC grade ‘‘B’’) may not be observed.
Questions that are difficult to answer are did the ROM
deficit contribute to OA or did the development of OA cause
a ROM deficit? Salmon et al,23 in a study that evaluated
patients at 5, 7, and 13 years after ACL reconstruction, found
an increase in the percentage of patients who had a loss of
normal knee extension from 2% at 5 years postoperatively
to 44% at 13 years postoperatively. Similarly, the percentage
of patients who had a loss of normal knee flexion increased
§
References 1, 11, 17, 18, 20, 23, 27, 28.
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112
Shelbourne et al
The American Journal of Sports Medicine
Figure 4 To feel a difference in extension kinesthetically, the
examiner passively extends the patient’s knee by holding the
thigh in place with one hand and using the other hand to hold
the ball of the foot to lift the heel off the examination table.
from 6% at 5 years to 21% at 13 years after surgery. They
also found a progression of OA with greater time after surgery, and a regression analysis determined that the loss of
knee extension was a factor related to OA.23 Conversely,
we found that very few patients (13%) lost knee ROM from
the time they were released to activities to the time of final
follow-up, and there were more patients (18%) who had
ROM deficits early that improved to the normal category at
follow-up. The prevalence of OA in this current study was
statistically significantly higher (53%) for patients who had
an overall IKDC ROM grade of abnormal at both early and
final follow-up compared with patients who maintained an
overall IKDC ROM grade as normal (39%). This finding leads
us to believe that ROM deficits that a patient has early after
surgery and continues to have with time may contribute to
OA in the long term.
The multivariate logistic regression analysis showed that
abnormal knee extension at final follow-up and abnormal
knee flexion at both early and final follow-up were equally
as significant as having a partial medial meniscectomy,
with patients having almost 2 times the odds of having OA.
The most important factor in the regression model was damaged articular cartilage with 2.1 times the odds of developing
OA. While each of these factors is important, rehabilitation to
achieve normal knee ROM may be easier to achieve than controlling the status of the meniscus or articular cartilage.
Most rehabilitation programs today with ACL reconstruction ‘‘allow’’ full ROM immediately after surgery. However,
there is a difference between allowing full ROM and emphasizing that full ROM needs to be obtained to achieve the optimal outcome after surgery. The senior author has used the
‘‘accelerated’’ rehabilitation program30 after ACL reconstruction since 1987; however, the program was meant to accelerate the return of ROM and strength, and the quicker return
to sports was a direct result of patients achieving those 2
specific rehabilitation goals. Regardless of the time restriction surgeons decide is appropriate for their patients to
return to activities, the goal of achieving full knee ROM, to
include hyperextension, can be a common goal for all
because patients who achieve full ROM and maintain it
through time may have less OA in the long term.
Throughout the years of the study, the methods used to
achieve full knee ROM were refined. We believe that there
were 2 main factors that helped patients achieve full ROM
after surgery: (1) delaying surgery after an acute injury so
patients could perform rehabilitation exercises to obtain
full ROM before surgery and (2) limiting the development
of a hemarthrosis after surgery. The protocol to limit
a hemarthrosis and pain after surgery has been
described26,29 and includes adequate pain control with
intravenous ketorolac and cold/compression with elevation
of the knee. An advantage to limiting a hemarthrosis is
that hemarthrosis can cause a quadriceps muscle shutdown, which further complicates obtaining terminal knee
extension and achieving good leg control. The goal of limiting an intra-articular hemarthrosis or effusion was central
to the progression of rehabilitation during the first year
after surgery. If a patient experienced increased swelling
with increased exercises or activities, he or she was told
to reduce the level of activity to eliminate the swelling
and to make sure full knee ROM was maintained.
Surgical procedures are being done with the intent to
prevent or minimize the development of OA after ACL
reconstruction, and the major surgical efforts being performed include double-bundle ACL reconstruction, meniscal transplant, and articular cartilage repair or
restoration.3,12,31 Given the results of this current study
showing that even a 3° to 5° extension loss or 5° flexion
loss can be associated with the prevalence of OA in the
long term, the results of these other surgical procedures
to reduce OA should also include a critical evaluation of
knee ROM as a factor for success or failure from surgery.
A limitation of this study is that we had 5-year objective
follow-up on 43% of patients. While, ideally, we would like to
achieve long-term follow-up on all patients, this goal is difficult to achieve in clinical practice. However, a previous
study28 of our patient population showed that the subjective
results of patients who could not return for long-term objective evaluation were not statistically significantly different
than the patients who did return. Therefore, we believe
the results of this study show a representative sample of
our total patient population.
CONCLUSION
The data in this study show that the prevalence of OA on
radiographs in the long term after ACL reconstruction is
lower in patients who achieve and maintain normal knee
ROM after ACL reconstruction, regardless of the status
of the meniscus. Proper perioperative rehabilitation to
achieve normal knee ROM may reduce the effect of partial
meniscectomy for developing OA after surgery.
ACKNOWLEDGMENT
We thank Kanitha Phalakornkule, MS, for her statistical
analysis of the data.
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Vol. 40, No. 1, 2012
ROM Loss and OA After ACL Reconstruction
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