[
RESEARCH REPORT
]
THOMAS G. SUTLIVE, PT, PhD, OCS¹š>;7J>;HF$BEF;P" DPT²š:7D?;$I9>D?JA;H"DPT²šI7H7>;$O7MD" DPT²
HE8;HJ@$>7BB;"DPT²šB?;CJ$C7DI<?;B:"MD³šHE8;HJ;$8EOB;I"PT, DSc, OCS, FAAOMPT4
@E>D:$9>?B:I"PT, PhD, MBA, OCS, FAAOMPT5
Development of a Clinical Prediction
Rule for Diagnosing Hip Osteoarthritis in
Individuals With Unilateral Hip Pain
steoarthritis (OA) is the most common form of arthritic
disorders and one of the most common reasons for visiting
a health care practitioner.27 The estimated annual cost of
managing OA in the United States is immense, accounting for
billions of dollars in healthcare expenditures.11,13,17 The hip is a common
site for OA, affecting 10% to 25% of the population over the age of
55.13,41 In addition to the economic impacts, decreased function
associated with hip OA can have a substantial detrimental effect on
O
TIJK:O:;I?=D0 Prospective cohort/predictive
validity study.
TE8@;9J?L;0 To determine the diagnostic accuracy of common clinical examination items and
to construct a preliminary clinical prediction rule
for diagnosing hip osteoarthritis (OA) in individuals
with unilateral hip pain.
T879A=HEKD:0 The current gold standard for
the diagnosis of hip OA is a standing anteroposterior (AP) radiograph of the pelvis. Other than for
Altman’s criteria, little research has been done to
determine the accuracy of clinical examination
findings for diagnosing hip OA.
TC;J>E:I7D:C;7IKH;I0 Seventy-two
subjects completed the study. Each subject
received a standardized history, physical examination, and standing AP radiograph of the pelvis.
Subjects with a Kellgren and Lawrence score of 2
or higher based on the radiographs were considered to have definitive hip OA. Likelihood ratios
(LRs) were computed to determine which clinical
examination findings were most diagnostic of hip
OA. Potential predictor variables were entered
into a logistic regression model to determine the
most accurate set of clinical examination items for
diagnosing hip OA.
TH;IKBJI0 Twenty-one (29%) of the 72 subjects
had radiographic evidence of hip OA. A clinical prediction rule consisting of 5 examination
variables was identified. If at least 4 of 5 variables
were present, the positive LR was equal to 24.3
(95% confidence interval: 4.4-142.1), increasing
the probability of hip OA to 91%.
T9ED9BKI?ED0 The preliminary clinical prediction rule provides the ability to a priori identify patients with hip pain who are likely to have hip OA.
A validation study should be done before the rule
can be implemented in routine clinical practice.
TB;L;BE<;L?:;D9;0 Diagnosis, level 2b.
J Orthop Sports Phys Ther 2008;38(9):542-550.
doi:10.2519/jospt.2008.2753
TA;OMEH:I0 arthritis, diagnosis, OA, predictive validity
quality of life. Although there is no cure
for hip OA, various forms of nonsurgical treatment have proven effective, including weight reduction, exercise, and
manual therapy interventions.20-22,43
Therefore, accurate diagnosis and timely
intervention is essential to minimize the
deleterious effects of OA and to maximize
functional abilities.9,25,40
Radiographs represent the current
gold standard for diagnosing hip OA.37
Osteoarthritis severity is determined
based on the presence of hallmark radiographic findings, such as joint space narrowing, osteophytes, bony changes at the
joint margins, and alterations of subchondral bone, according to the Kellgren and
Lawrence scale.26,37 Although radiographs
are relatively inexpensive, understanding
the diagnostic accuracy of key clinical examination findings would assist the clinician in expediting the evaluation process,
initiating early management, and making
appropriate referrals to specialty providers, and may obviate unnecessary radiation exposure.
Altman and colleagues1 identified several elements of the clinical examination
that are diagnostic of hip OA in patients
with hip pain. Although these criteria have
proven to be valuable for decision mak-
1
Associate Professor, US Army-Baylor University Doctoral Program in Physical Therapy, San Antonio, TX. 2 Doctoral student, US Army-Baylor University Doctoral Program in
Physical Therapy, San Antonio, TX. 3 Chief, Musculoskeletal Section, Department of Radiology and Radiology Residency Program Director, Brooke Army Medical Center, San
Antonio, TX. 4 Assistant Professor, US Army-Baylor University Doctoral Program in Physical Therapy, San Antonio, TX. 5 Assistant Professor and Director of Research, US ArmyBaylor University Doctoral Program in Physical Therapy, San Antonio, TX. The protocol for this study was approved by The Institutional Review Board of Brooke Army Medical
Center. The opinions or assertions herein are the private views of the authors and are not to be construed as official or as reflecting the views of the United States Army or the
Department of Defense. Address correspondence to Thomas G. Sutlive, US Army-Baylor University Doctoral Program in Physical Therapy, 3150 Stanley Road, Room 1303, ATTN:
MCCS-HMT, Fort Sam Houston, TX 78234. E-mail: thomas.sutlive@amedd.army.mil
542 | september 2008 | volume 38 | number 9 | journal of orthopaedic & sports physical therapy
the diagnostic accuracy of commonly used
clinical examination procedures thought
to be suggestive of hip OA, but that may
have not previously been considered by
Altman’s criteria, and to develop a preliminary clinical prediction rule that maximizes the accuracy of diagnosing hip OA,
based on clinical examination findings.
METHODS
<?=KH;'$Measurement of the Patrick’s test using an
inclinometer.
ing,2,21,22,35,40 their utilization may require
laboratory testing, such as erythrocyte
sedimentation rate (ESR). Additionally,
the development of these criteria did not
include several clinical examination findings commonly thought to be associated
with hip OA, such as the presence of a
capsular pattern of motion restriction,
identification of certain abnormal end
feels at the end range of passive rangeof-motion testing, and reproduction of
a patient’s pain with provocative testing.
Cyriax10 stated that a capsular pattern is
a unique pattern of range-of-motion restrictions that is suggestive of OA. For
the hip, Cyriax stated that the capsular
pattern consisted of a gross limitation in
internal rotation, flexion, and abduction.
It was also suggested that an early capsular end feel, a spasm end feel (in the
absence of acute trauma), and a boneto-bone end feel may indicate possible
degenerative changes at the hip.10 Clinical examination procedures, such as the
Patrick’s test, hip flexion test, scour test,
and squat test, are also commonly used
by clinicians in the assessment of patients
with hip pain31 and designed to reproduce a patient’s symptoms (“provocative
tests”). These tests are frequently used to
determine the location and irritability of
a patient’s symptoms and to select appropriate treatment interventions.
Although preliminary evidence suggests that positive findings from these
procedures may be useful in diagnosing
hip OA, their diagnostic accuracy has not
been thoroughly studied. Therefore, the
purposes of this study were to determine
Subjects
M
e utilized a single-group,
cross-sectional study design to
determine the diagnostic accuracy of selected special tests and measures
for the diagnosis of hip OA. Seventyeight subjects were recruited from the
military healthcare beneficiary system at
Fort Sam Houston in San Antonio, TX.
Volunteers were required to be over 40
years of age and have a chief complaint
of unilateral pain in the buttock, groin,
or anterior thigh. We excluded patients
with a current diagnosis of cancer, history of hip surgery, and females who were
pregnant at the time of the study. Urine
pregnancy tests were performed on all
premenopausal females. The study was
approved by the Brooke Army Medical
Center (San Antonio, Texas) Institutional
Review Board, and all patients provided
consent prior to their participation.
;nWc_dWj_edFheY[Zkh[i
Each subject received a standardized history and physical examination by physical
therapists in the US Army-Baylor University Doctoral Program in Physical Therapy. Examiner teams were comprised of 2
physical therapist doctoral students, with
one serving as the examiner and the other
as a recorder. Examiners underwent a
standardized training regimen prior to
the beginning of data collection to develop consistent measurements based on
the operational definitions for the clinical
examination procedures. Examiners completed several training sessions to standardize the measurements in accordance
with the operational definitions, followed
by a final testing session to establish pilot
<?=KH;($Measurement of passive hip internal
rotation using an inclinometer.
reliability data in a sample of 10 healthy
subjects. The first 30 subjects enrolled in
the study were also assessed by teams of
2 examiner blinded to each other’s findings to establish definitive reliability
of the testing procedures. The physical
examination included range-of-motion
measurements, end feel testing according
to Cyriax, and 3 provocative maneuvers:
Patrick’s test (<?=KH;'), the scour test, and
the squat test. Operational definitions of
the physical examination items are provided in the 7FF;D:?N to facilitate replication of our study. The positional order of
testing (ie, standing, supine, prone) was
counterbalanced to mitigate the potential
for an order effect to occur.
Range of motion for hip flexion, extension, abduction, and adduction were
obtained using a standard 18-cm plastic
goniometer. An inclinometer was used
to assess range of motion for hip internal and external rotation (<?=KH;(). Immediately following each measurement,
subjects were asked whether the movement changed their symptoms. To assess
end feels, examiners utilized standardized passive range-of-motion assessment
techniques with overpressure. End feels
were recorded into 1 of 7 categories as
defined by Cyriax10: bone to bone, spasm,
early capsular, capsular, tissue approximation, empty, and springy. For the
purposes of data analysis, end feels were
dichotomized into capsular and noncapsular. According to Cyriax,10 the end feels
of early capsular, spasm, and bone-tobone are considered capsular end feels
and indicative of degenerative changes of
journal of orthopaedic & sports physical therapy | volume 38 | number 9 | september 2008 | 543
[
RESEARCH REPORT
J78B;'
=hWZ[
]
Kellgren and Lawrence Grading Scale
for Hip Osteoarthritis26
HWZ_e]hWf^_Y<_dZ_d]i
0
No evidence of joint space narrowing, osteophyte formation, or sclerosis (normal radiograph)
1
Possible narrowing of the joint space medially and possible osteophytes around the femoral head
2
Definite narrowing of the joint space, definite osteophytes, and slight sclerosis
3
Marked narrowing of the joint space, slight osteophytes, some sclerosis, and cyst formation, and deformity of
4
Gross loss of joint space with sclerosis and cysts, marked deformity of femoral head and acetabulum,
the femoral head and acetabulum
<?=KH;)$Standing antero-posterior radiograph of
the pelvis, with evidence of Kellgren and Lawrence
grade 4 osteoarthritis in both hips.
the joint. End feels classified as noncapsular included soft tissue approximation,
capsular (ie, normal resistance of the
capsule at the end range of some joints),
springy block, and empty end feels. We
also recorded the effect of the movement
on the patient’s symptoms, such as pain
location (verified by the subject pointing
to the site of pain) and replication of previous pain for each measurement.
Cyriax10 stated that the capsular pattern of restriction for the hip was gross
limitation of internal rotation, flexion,
and abduction, and that this pattern was
suggestive of hip OA. He also stated that
in very early hip arthrosis, internal rotation is the first movement to become
restricted, followed by flexion.10 Based
on Cyriax’s definitions, we determined
whether a capsular pattern of restriction
existed in our subjects based on fulfillment of 1 of the 2 following conditions: (1)
loss of hip internal rotation greater than
loss of hip flexion greater than loss of hip
abduction, or (2) loss of hip internal rotation greater than loss of hip abduction
greater than loss of hip flexion. Loss of
each range of motion was expressed as a
percentage of restricted motion based on
published normal values.15 For example,
based on a published normal value of 45°,
a subject with 35° of hip internal rotation
was considered to have a 10° restriction
or a 22% (10/45) loss of motion.15
HWZ_e]hWf^i
Following the physical examination, each
subject received a standing antero-poste-
large osteophytes
Demographics and Baseline
Characteristics of Subjects
J78B;(
LWh_WXb[
7bbIkX`[Yji
d3-(
>_fE7Fh[i[dj
d3('
>_fE77Xi[dj
d3+'
P Value*
Age, mean y (SD)
58.6 (11.2)
61.1 (12.7)
58.3 (10.6)
.36
Gender, n (%) females
40 (56%)
7 (10%)
33 (46%)
.02
2.8 (2.3)
3.4 (2.8)
2.5 (2.1)
Current pain, mean (SD)†
Duration of symptoms, n
6 wk
2
0
2
6 wk-6 mo
9
0
9
6 mo-1 y
7
3
4
1-5 y
32
10
22
5 y
22
8
14
46
14
32
Mode of onset, n
Gradual
.03
.22
.05
Sudden (minutes with no perturbation)
14
1
13
Sudden (traumatic)
12
6
6
Lumbar spine
45
16
29
.42
Buttock
36
14
22
.14
Groin
15
8
7
.04
Anterior thigh
19
7
12
.43
Posterior thigh
18
5
13
.38
Lower leg/foot
24
9
15
.61
Location of symptoms, n
Abbreviation: OA, osteoarthritis.
* Difference between groups.
†
Numeric pain rating scale: 0 to 10, with 0 as no pain and 10 as the worst possible pain.
rior (AP) radiograph of the pelvis (<?=KH;
3). The average SD number of days between the physical examination and radiographic testing was 5.8 9.5 days (range,
0-46 days), and the median was 1.5 days.
All radiographs were examined and scored
by the same staff radiologist who had more
than 15 years of experience in musculoskeletal imaging. Scoring was based on
the Kellgren and Lawrence scale (J78B;
1).26 The Kellgren and Lawrence grading
scheme has proven to be reliable16 and has
been accepted by the World Health Organization as the reference standard for
cross-sectional and longitudinal studies
of hip OA.37 Subjects with a Kellgren and
Lawrence score of 2 or higher were considered to have hip OA.24,34,37 The radiologist
and examiners were blinded to each other’s findings to eliminate the potential for
544 | september 2008 | volume 38 | number 9 | journal of orthopaedic & sports physical therapy
J78B;)
Interrater Reliability (ICC2,1), SEM, and
MDC for Hip Range of Motion Measurements,
the Squat, and Patrick’s Test
?992,1/+9?
I;C
Flexion
LWh_WXb[
0.85 (0.64 to 0.93)
2.0°
C:9
5.5°
Abduction
0.85 (0.68 to 0.93)
1.6°
4.4°
Adduction
0.54 (–0.19 to 0.81)
0.9°
2.5°
External rotation
0.77 (0.53 to 0.89)
1.7°
4.7°
Internal rotation
0.88 (0.74 to 0.94)
1.8°
5.0°
Extension
0.68 (0.32 to 0.85)
0.7°
1.9°
Squat
0.80 (0.59 to 0.91)
1.4°
3.9°
Patrick’s test
0.90 (0.78 to 0.96)
2.6°
7.2°
Abbreviations: CI, confidence interval; ICC, intraclass correlation coefficient; MDC, minimum detectable change; SEM, standard error of the measurement.
J78B;*
Percent Agreement for Hip End
Feel Dichotomized Into Capsular and
Noncapsular End Feels
LWh_WXb[
AWffW9e[øY_[dj/+9?
F[hY[dj7]h[[c[dj
Flexion (involved side)
0.21 (–0.22 to 0.64)
70.0
Internal rotation (involved side)
0.51 (0.19 to 0.83)
76.7
Scour test (involved side)
0.52 (0.08 to 0.96)
86.7
Patrick’s test (involved side)
0.47 (0.12 to 0.81)
76.7
Hip flexion test (involved side)
0.52 (0.09 to 0.96)
86.7
Abbreviation: CI, confidence interval.
rater bias. Only clinical examination data
from the patient’s self-reported symptomatic side were considered for subjects who
were judged to have bilateral radiographic
evidence of hip OA.
Data Analysis
All statistical analyses were performed
using SPSS software, Version 12.0 (SPSS
Inc, Chicago, IL). Descriptive statistics
and measures of central tendency and
variability were calculated to summarize the demographic characteristics of
the sample. Descriptive statistics and
interrater reliability coefficients were
determined for each of the physical examination items. Interrater reliability
coefficients were calculated using Cohen’s
kappa coefficient and percent agreement
for categorical variables and intraclass
correlation coefficients (ICC2,1) for continuous variables. Standard errors of the
measurement (SEM) were determined
for each of the continuous variables according to the following equation: SD
•(1 – ICC). The minimum detectable
change (MDC) was calculated as SEM 1.96 (z score for 95% confidence) •2.
Individual variables from the history
and physical examination were tested for
their association with the radiograph reference criterion using independent-samples t tests for continuous variables and
D2 tests for categorical variables. Variables
with a significance level of P.10 were
retained as potential predictors. A more
liberal P value was utilized to avoid eliminating potentially meaningful variables
during the initial screening process. For
continuous variables with a significant
univariate relationship, sensitivity and
specificity values were calculated for all
possible cutoff points and then plotted as
a receiver operator characteristic (ROC)
curve. The point on the curve nearest the
upper left-hand corner represented the
value with the best diagnostic accuracy,
and this point was selected as the cut-off
defining a positive test. Sensitivity, specificity, and positive and negative likelihood
ratios (LR) were calculated for potential
predictor variables. Potential predictor
variables were entered into a stepwise logistic regression model to determine the
most accurate set of variables for prediction of diagnostic success. A significance
level of greater than .10 was required for
removal from the equation to minimize
the likelihood of excluding potentially
helpful variables. Variables retained in
the regression model were used to formulate the clinical prediction rule.
H;IKBJI
S
eventy-eight volunteers were
recruited for this study. Six subjects
failed to complete their radiograph
examination. Seventy-two subjects (40
female, 32 male; mean SD age, 58.6 11.2 years) completed the study. Demographic and baseline characteristics are
shown in J78B; (. Twenty-one of the 72
subjects were classified as having hip OA,
resulting in a pretest probability of 29%
(21/72). The number of subjects who had
Kellgren and Lawrence scores of 0, 1, 2, 3,
and 4 were 19 (26%), 32 (44%), 13 (18%),
3 (4%), and 5 (7%), respectively.
H[b_WX_b_jo
Interrater reliability (ICC2,1) and 95% confidence intervals (CIs) for range-of-motion
measurements, squat test, and Patrick’s
tests are shown in J78B;). Values ranged
from 0.54 to 0.90. The kappa coefficients
with 95% CIs for end feel testing ranged
from 0.21 to 0.52 (J78B;*). Because of the
low prevalence of some end feel categories
and limited variability between examiners,
kappa coefficients might have been artificially deflated.39 Therefore, we also calculated percent agreement, which ranged
from 70.0% to 86.7% (J78B;*).39
:_W]deij_Y7YYkhWYo
The sensitivity, specificity, and positive
likelihood ratios for individual variables
journal of orthopaedic & sports physical therapy | volume 38 | number 9 | september 2008 | 545
[
J78B;+
]
RESEARCH REPORT
Sensitivity, Specificity, and Likelihood Ratios (95% CI) for Individual Variables
With a Significant Relationship With Positive Radiographic Findings
LWh_WXb[
I[di_j_l_jo
If[Y_ÓY_jo
Fei_j_l[B_a[b_^eeZHWj_e
D[]Wj_l[B_a[b_^eeZHWj_e
0.52 (0.28 to 0.96)
Gender
0.67 (0.43 to 0.85)
0.65 (0.50 to 0.77)
1.9 (1.1 to 3.0)
Constant LBP/buttock pain
0.52 (0.30 to 0.74)
0.92 (0.80 to 0.97)
6.4 (2.4 to 17.4)
0.52 (0.33 to 0.81)
Groin pain same side
0.29 (0.12 to 0.52)
0.92 (0.80 to 0.97)
3.6 (1.2 to 11.0)
0.78 (0.59 to 1.00)
Self-reported squatting as aggravating factor
0.76 (0.52 to 0.91)
0.57 (0.42 to 0.70)
1.8 (1.2 to 2.6)
0.42 (0.19 to 0.93)
Squat causing posterior pain
0.24 (0.09 to 0.48)
0.96 (0.85 to 0.99)
6.1 (1.5 to 25.6)
0.79 (0.62 to 1.00)
Active hip flexion causing lateral pain
0.43 (0.23 to 0.66)
0.88 (0.75 to 0.95)
3.6 (1.5 to 8.7)
0.65 (0.44 to 0.94)
Scour with adduction causing lateral or groin pain
0.62 (0.39 to 0.81)
0.75 (0.60 to 0.85)
2.4 (1.4 to 4.3)
0.51 (0.29 to 0.89)
Passive IR g25°
0.76 (0.52 to 0.91)
0.61 (0.46 to 0.74)
1.9 (1.3 to 3.0)
0.39 (0.18 to 0.86)
Patrick’s 60°
0.57 (0.34 to 0.77)
0.71 (0.56 to 0.82)
1.9 (1.1 to 3.4)
0.61 (0.36 to 1.00)
Active hip extension causing hip pain
0.52 (0.30 to 0.74)
0.80 (0.66 to 0.90)
2.7 (1.3 to 5.3)
0.59 (0.37 to 0.94)
Abduction or adduction causing groin pain
0.33 (0.15 to 0.57)
0.94 (0.83 to 0.98)
5.7 (1.7 to 18.6)
0.71 (0.52 to 0.96)
Abbreviations: CI, confidence interval; IR, internal rotation; LBP, low back pain.
demonstrating a significant relationship
with positive radiographic findings are
shown in J78B; +. The 5 variables that
emerged from the subsequent logistic regression analysis were used to form the
preliminary clinical prediction rule: (1)
self-reported squatting as an aggravating factor; (2) active hip flexion causing
lateral hip pain; (3) scour test with adduction causing lateral hip or groin pain;
(4) active hip extension causing pain; and
(5) passive internal rotation of less than
or equal to 25° (J78B;I, and -). Having at
least 3 out of the 5 predictor variables resulted in a positive likelihood ratio equal
to 5.2 (95% CI: 2.6-10.9), increasing the
likelihood of having hip OA from a pretest probability of 29% to a 68% posttest
probability. If at least 4 out of 5 variables
were present, the positive likelihood ratio was equal to 24.3 (95% CI: 4.4-142.1),
increasing the posttest probability of having hip OA to 91%.
DISCUSSION
T
he ability to identify patients
with hip OA based on key clinical examination findings is useful to guide
diagnostic decision making and to assist
clinicians in determining which patients
require further testing and evaluation,
and when to initiate early management,
which may minimize the deleterious ef-
The Number of Subjects in
Each Group at Each Level*
J78B;,
DkcX[he\Fh[Z_YjehLWh_WXb[iFh[i[dj
AB=hWZ[(
5
1 (1.4%)
AB=hWZ[l2
3 (4.2%)
l4
1 (1.4%)
10 (13.9%)
l3
7 (9.7%)
15 (20.1%)
l2
20 (27.8%)
17 (23.6%)
l1
42 (58.3%)
20 (27.8%)
0
9 (12.5%)
1 (1.4%)
Abbreviation: K & L, Kellgren and Lawrence.
* The 5 variables forming the clinical prediction rule are (1) self-reported squatting as an aggravating
factor, (2) scour test with adduction causing groin or lateral pain, (3) active hip flexion causing lateral
pain, (4) active hip extension causing hip pain, and (5) passive hip internal rotation less than or
equal to 25°. Scores are n (%).
fects of hip OA and maximize function.
Improving the clinical diagnosis of hip
OA may also minimize the costs associated with unnecessary radiographic
procedures and avoid the risks of radiation exposure. Each variable retained in
the final clinical prediction rule demonstrated moderate to good reliability,29,36
falling within the ranges of those previously reported.9,12,18,23 We chose to report
the positive likelihood ratio because the
purpose of this study was to maximize the
potential of making an accurate diagnosis
of hip OA, while minimizing the potential
of false positive findings.6,14 Furthermore,
requiring that subjects had at least Kellgren and Lawrence grade 2 radiographic
changes increased the likelihood that
they would experience clinically relevant
symptoms and might benefit from nonsurgical management.
Twenty-one of the 72 subjects in our
study had a Kellgren and Lawrence score
of equal or greater to 2, based on their
radiographs. Thus the pretest probability of having hip OA in our sample was
29%. If a subject exhibited only 1 or 2 of
the predictor variables, the posttest probability of having hip OA only increased
to 33% and 46%, respectively (J78B;,).
However, if a subject had at least 3 predictors present, the likelihood of having
hip OA increased from 29% to 68%. If a
subject exhibited at least 4 of the 5 predictors, the posttest probability increased
further to 91%. However, this latter com-
546 | september 2008 | volume 38 | number 9 | journal of orthopaedic & sports physical therapy
Combination of Predictor Variables and Associated Accuracy
Statistics With 95% Confidence Intervals
J78B;DkcX[he\
Fh[Z_YjehiFh[i[dj
I[di_j_l_jo/+9?
If[Y_ÓY_jo/+9?
Fei_j_l[B_a[b_^eeZ
HWj_e/+9?
D[]Wj_l[B_a[b_^eeZ
HWj_e/+9?
Feij#j[ijFheXWX_b_jo
e\>_fE7/+9?
75 (25 to 96)
5
.14 (.04 to .37)
.98 (.88 to 1.0)
7.3 (1.1 to 49.1)
.87 (.73 to 1.1)
l4
.48 (.26 to .70)
.98 (.88 to 1.0)
24.3 (4.4 to 142.1)
.53 (.35 to .80)
91 (58 to 99)
l3
.71 (.48 to .88)
.86 (.73 to .94)
5.2 (2.6 to 10.9)
.33 (.17 to .66)
68 (51 to 82)
l2
.81 (.57 to .94)
.61 (.46 to .74)
2.1 (1.4 to 3.1)
.31 (.13 to .78)
46 (36 to 56)
l1
.95 (.74 to 1.0)
.18 (.09 to .31)
1.2 (.99 to 1.4)
.27 (.04 to 2.0)
33 (29 to 36)
Abbreviations: CI, confidence interval; OA, osteoarthritis.
* The posttest probability of diagnosis of hip OA is calculated using the positive likelihood ratio and assumes 29% of patients have hip OA (our study prevalence) regardless of number of predictors present.
bination of predictors was associated
with a wide 95% CI, creating uncertainty
as to the stability of this point estimate.
If the intent is to conservatively estimate
when to order imaging studies, refer patients to specialty providers, or to initiate
appropriate nonsurgical management, a
reasonably sufficient degree of diagnostic
accuracy exists based on the presence of
at least 3 predictors.
Altman and colleagues1 described
clinical examination variables that are
commonly used for establishing a diagnosis of patients with hip OA. According
to their study, a patient was classified as
having hip OA if they presented with hip
pain and either (1) hip internal rotation
greater than or equal to 15°, pain present
on internal rotation of the hip, morning
stiffness of the hip for less than or equal to
60 minutes, and an age of greater than 50
years, or (2) hip internal rotation of less
than 15° and an ESR less than or equal
to 45 mm/h. If no ESR was obtained, hip
flexion less than or equal to 115° was substituted. Either of these sets of criteria had
a sensitivity of 86%, a specificity of 75%,
and a positive likelihood ratio of 3.4 for
the diagnosis of hip OA, with radiographs
serving as the reference standard. However, Altman et al’s criteria were based on a
limited examination and did not consider
a number of routinely used tests and measures that are thought to be diagnostic of
hip OA. Therefore, we believed that it was
necessary to examine the diagnostic accuracy of these additional clinical examination procedures. Hip pain and limited hip
internal rotation were common predictors
of hip OA in both our study (J78B;,) and
the clinical criteria reported by Altman
and colleagues.1 Although a limitation
of hip flexion range of motion was one of
Altman et al’s criteria, it was not retained
as a variable in our final rule. However,
active hip flexion that reproduced symptoms was predictive of hip OA.
Cyriax10 proposed that each joint
might have a characteristic proportional
pattern of motion restriction that, when
detected, indicates the presence of a capsular pattern, which is suggestive of a
lesion to the synovial membrane of the
joint. Cyriax described the capsular pattern of the hip to be a marked limitation
of internal rotation followed by losses of
flexion and abduction. He further postulated that in the early onset of hip OA,
internal rotation is the first movement to
be measurably restricted, followed by a
slight flexion limitation.10 The emphasis
on internal rotation followed by flexion
appears to correlate with the results of
recent studies on clinical indicators of
hip joint OA.1,42 While limited hip internal rotation emerged as a predictor
of hip OA in our study, the presence of
a capsular pattern of restriction did not
emerge in the final rule. This finding is
consistent with previous reports questioning the concept of a capsular pattern
of restriction of the hip.4,28 Klassbo and
colleagues28 examined 168 patients with a
variety of hip disorders and found no evidence to support the existence of a capsular pattern in their subjects who had hip
OA. Similarly, Bijl et al4 examined the
validity of the concept of a capsular pattern in patients with a clinical diagnosis
of hip or knee OA, and concluded that the
capsular pattern cannot be regarded as a
valid test for the diagnosis of OA in either
of these patient populations.
To our knowledge, no previous investigation has determined reliability for
the end feel assessment of hip motions.
Prior studies have shown that intrarater
reliability for the determination of knee
and shoulder end feels is moderate and
that interrater reliability is low.5,19 Chesworth et al5 reported moderate intrarater
kappa coefficients and substantial interrater kappa values for the assessment of
shoulder lateral rotation in patients with
shoulder disorders. Hayes and Petersen5,19
reported kappa values ranging from –0.01
to 0.70 in their study of subjects with unilateral knee or shoulder pain. However,
their values for percent agreement were
generally high, which was consistent with
our findings for end feel assessment of
hip internal rotation and flexion (J78B;)).
Although end feel assessment of hip internal rotation or flexion did not emerge
as a predictor of hip OA, the interrater
reliability established in this study may
help to improve the clinician’s confidence
in utilizing these techniques during the
examination of patients with hip pain.
Our study includes several limitations.
It is important to note that the diagnostic
accuracy of the rule actually diminished
when all 5 predictors were present. However, only 4 subjects had all 5 criteria
journal of orthopaedic & sports physical therapy | volume 38 | number 9 | september 2008 | 547
[
present. Because 1 of these subjects did
not have hip OA, the low total number
of subjects magnified this error. Larger
studies with more individuals having all 5
criteria present would likely demonstrate
higher levels of diagnostic accuracy were
all 5 criteria present. Additionally, while
11 variables were entered into the logistic
regression analysis, only 21 subjects exhibited a positive response to those variables. It is possible that the small sample
of positive findings and the number of
variables entered into the logistic regression may have resulted in overfitting of
the model, which could have led to spurious findings. However, in the development stage of a clinical prediction rule it
is important and necessary to include all
the potential predictor variables, and any
variable that may have been identified
as a predictor should be re-examined in
future validation studies.8 We also considered a limited number of examination
procedures performed primarily by physical therapists and other practitioners who
examine patients in a musculoskeletal or
orthopedic clinical setting. The clinical
examination procedures included in this
study were chosen because they are routinely performed during the examination
of patients with hip pain, allowing comparison of our results with previous work.1
It is also possible that some of the predictor variables emerged by chance. Therefore, future studies done in a variety of
clinical practice settings and populations
are necessary to replicate and validate
our findings before being recommended
for widespread use in clinical practice.32
If the rule is validated, an impact analysis should be conducted to determine the
impact of the rule on decreasing radiographic utilization, clinical practice patterns, outcomes, and costs of care. The
eventual value of the rule may be to help
clinicians determine when to initiate nonsurgical management strategies, such as
physical therapy, that have proven to be
effective for patients with hip OA.21,22,30
Alternatively, clinicians may be interested in ruling out hip OA as a significant
contributor to hip pain. Therefore, future
RESEARCH REPORT
investigations may also explore the best
combination of clinical factors for ruling
out the diagnosis of hip OA.
CONCLUSION
M
e have completed the first
step in the development of a
preliminary rule that identifies
patients with hip OA. We believe that
the results of this study may assist clinicians in expediting the evaluation process, initiating early management, and
making appropriate referrals to specialty
providers in this patient population. Future studies to replicate and validate our
findings are necessary before the rule can
be recommended for widespread use in
clinical practice. T
A;OFE?DJI
<?D:?D=I0 A preliminary clinical predic-
tion rule was developed for identifying
patients with hip osteoarthritis (OA)
based on key clinical examination criteria.
?CFB?97J?ED0 The clinical prediction rule
developed in this study may assist clinicians in expediting the evaluation process, initiating early management, and
making appropriate referrals of patients
with hip OA.
97KJ?ED0 This study involved a small
sample size (n = 72) and must be validated in replication studies in a variety
of clinical settings and populations before it can be advocated for widespread
clinical use.
H;<;H;D9;I
1. Altman R, Alarcon G, Appelrouth D, et al. The
American College of Rheumatology criteria for
the classification and reporting of osteoarthritis
of the hip. Arthritis Rheum. 1991;34:505-514.
2. Bierma-Zeinstra S, Bohnen A, Ginai A, Prins A,
Verhaar J. Validity of American College of Rheumatology criteria for diagnosing hip osteoarthritis in primary care research. J Rheumatol.
1999;26:1129-1133.
3. Bierma-Zeinstra SM, Bohnen AM, Ramlal R,
Ridderikhoff J, Verhaar JA, Prins A. Comparison
between two devices for measuring hip joint mo-
]
tions. Clin Rehabil. 1998;12:497-505.
4. Bijl D, Dekker J, van Baar ME, et al. Validity of
Cyriax’s concept capsular pattern for the diagnosis of osteoarthritis of hip and/or knee. Scand
J Rheumatol. 1998;27:347-351.
5. Chesworth BM, MacDermid JC, Roth JH, Patterson SD. Movement diagram and “end-feel”
reliability when measuring passive lateral rotation of the shoulder in patients with shoulder
pathology. Phys Ther. 1998;78:593-601.
,$ Childs JD, Cleland JA. Development and application of clinical prediction rules to improve
decision making in physical therapist practice.
Phys Ther. 2006;86:122-131.
-$ Cliborne AV, Wainner RS, Rhon DI, et al. Clinical
hip tests and a functional squat test in patients
with knee osteoarthritis: reliability, prevalence of
positive test findings, and short-term response
to hip mobilization. J Orthop Sports Phys Ther.
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8. Concato J, Feinstein AR, Holford TR. The risk of
determining risk with multivariable models. Ann
Intern Med. 1993;118:201-210.
/$ Croft P, Cooper C, Wickham C, Coggon D. Defining osteoarthritis of the hip for epidemiologic
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11. Elders MJ. The increasing impact of arthritis on
public health. J Rheumatol Suppl. 2000;60:6-8.
12. Ellison JB, Rose SJ, Sahrmann SA. Patterns
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between healthy subjects and patients with low
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13. Felson DT. Epidemiology of hip and knee osteoarthritis. Epidemiol Rev. 1988;10:1-28.
14. Flynn T, Fritz J, Whitman J, et al. A clinical
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low back pain who demonstrate short-term
improvement with spinal manipulation.
Spine. 2002;27:2835-2843. http://dx.doi.
org/10.1097/01.BRS.0000035681.33747.8D
15. Greene WB, Heckman J. Clinical Measurement
of Joint Motion. Chapel Hill, NC: American Academy of Orthopedic Surgeons; 1994.
',$ Gunther KP, Sun Y. Reliability of radiographic
assessment in hip and knee osteoarthritis.
Osteoarthritis Cartilage. 1999;7:239-246. http://
dx.doi.org/10.1053/joca.1998.0152
'-$ Gupta S, Hawker GA, Laporte A, Croxford R,
Coyte PC. The economic burden of disabling hip
and knee osteoarthritis (OA) from the perspective of individuals living with this condition.
Rheumatology (Oxford). 2005;44:1531-1537.
http://dx.doi.org/10.1093/rheumatology/kei049
18. Hayes KW, Petersen C, Falconer J. An examination of Cyriax’s passive motion tests with
patients having osteoarthritis of the knee. Phys
Ther. 1994;74:697-707; discussion 707-699.
'/$ Hayes KW, Petersen CM. Reliability of assessing
end-feel and pain and resistance sequence in
subjects with painful shoulders and knees. J
Orthop Sports Phys Ther. 2001;31:432-445.
20. Hochberg MC, Altman RD, Brandt KD, et al.
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22.
23.
24.
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(,$
(-$
28.
Guidelines for the medical management of
osteoarthritis. Part I. Osteoarthritis of the hip.
American College of Rheumatology. Arthritis
Rheum. 1995;38:1535-1540.
Hoeksma HL, Dekker J, Ronday HK, Breedveld
FC, Van den Ende CH. Manual therapy in osteoarthritis of the hip: outcome in subgroups of
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keh482
Hoeksma HL, Dekker J, Ronday HK, et al. Comparison of manual therapy and exercise therapy
in osteoarthritis of the hip: a randomized clinical
trial. Arthritis Rheum. 2004;51:722-729. http://
dx.doi.org/10.1002/art.20685
Holm I, Bolstad B, Lutken T, Ervik A, Rokkum
M, Steen H. Reliability of goniometric measurements and visual estimates of hip ROM in
patients with osteoarthrosis. Physiother Res Int.
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Ingvarsson T, Hagglund G, Lindberg H, Lohmander LS. Assessment of primary hip osteoarthritis: comparison of radiographic methods
using colon radiographs. Ann Rheum Dis.
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Klassbo M, Harms-Ringdahl K, Larsson G.
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(/$ Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33:159-174.
30. MacDonald CW, Whitman JM, Cleland JA, Smith
M, Hoeksma HL. Clinical outcomes following
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osteoarthritis: a case series. J Orthop Sports
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32. McGinn TG, Guyatt GH, Wyer PC, Naylor CD,
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),$ Portney L, Watkins M. Foundations of Clinical
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@
CEH;?D<EHC7J?ED
WWW.JOSPT.ORG
7FF;D:?N
EF;H7J?ED7B:;<?D?J?EDIE<J;IJI7D:C;7IKH;I
The physical examination included range-of-motion measurements, end feel
testing according to Cyriax,10 and provocative tests such as the scour test,
Patrick’s test, and squat test. Range of motion for hip flexion, extension,
abduction, and adduction was obtained using a standard 18-cm plastic
goniometer.3 An inclinometer was used to assess range of motion for hip
internal and external rotation.12 Before each of the range-of-motion measurements was taken, an assessment of mobility of the involved hip relative
to the uninvolved hip (normal, hypomobile, hypermobile) and end feel assessment was made. The effect of the movement on the patient’s symptoms
was also recorded (pain, no pain, location of pain).
Squat Test
The patient was standing with the feet aligned on a 20-cm strip of tape
placed on the floor. The big toe of each foot was positioned at each end
of the tape. With the patient in upright stance, the therapist “zeroed out”
the inclinometer along the tibial shaft approximately 1 to 2 cm below the
tibial tuberosity on the involved side. While looking straight ahead, patients
were instructed to keep the trunk upright, with hands on hips, and squat
as if they were trying to lower their buttocks between their feet as far as
possible, keeping the knees in line with the second toe and the heels on the
floor. Maximum squat was achieved either when the patient reported being
unable to go further due to pain limitations, was noticed to begin leaning
forward, or if the heels began to lift off the ground. Once maximum squat
was achieved, the range-of-motion measurement was recorded to the nearest degree, and any change in symptoms was recorded.7
IYekhJ[ij
The subject was supine. The hip was passively flexed to 90º and comfortable knee flexion was allowed to follow. The knee was then moved toward
the opposite shoulder and an axial load was applied in a direction parallel
to the long axis of the femur. The examiner judged the test to be positive or
negative based on the provocation of the patient’s symptoms in the groin.
Internal rotation and axial compression and then adduction and axial compression were added, with overpressure applied to the lateral surface of
journal of orthopaedic & sports physical therapy | volume 38 | number 9 | september 2008 | 549
[
RESEARCH REPORT
]
7FF;D:?N9EDJ?DK;:
the knee. The examiner also judged this part of the test to be positive or
negative based on the provocation of the subject’s symptoms in the hip or
groin.31
>_f<b[n_ed
The patient was supine. The hip was maintained in neutral abduction/adduction and rotation. The patient was instructed to flex the knee and hip of
the opposite extremity to be measured to maintain a neutral lumbar spine
position during the measurement. The lower extremity was held in that
position, and the subject was then instructed to actively flex the tested hip
as far as possible. The examiner observed the motion, making sure that the
patient did not rotate the hips posteriorly or externally rotate at the hip. The
range of motion was measured for each hip using a universal goniometer.
The fulcrum was centered over the greater trochanter, the proximal arm
along the midline of the pelvis, and the distal arm along the midline of the
femur, in line with the lateral femoral epicondyle.3,33
>_f7XZkYj_ed
The patient was supine. The hip was maintained in neutral flexion/extension
and rotation. The patient was instructed to actively move his/her hip to a
position of maximum abduction. Next, the range of motion was measured
using a universal goniometer. The fulcrum was centered over the anterior
superior iliac spine (ASIS) of the side being measured, the proximal arm
along a line joining the ASIS, and the distal arm along the midline of the
thigh.3,33
>_f7ZZkYj_ed
The patient was supine. The hip was maintained in neutral flexion/extension and rotation. The patient was instructed to actively move the hip to a
position of maximum adduction. Next, the range of motion was measured
using a universal goniometer. The fulcrum was centered over the ASIS, the
proximal arm along a line joining the ASIS, and the distal arm along the
midline of the femur. A second examiner held the untested extremity in hip
flexion to allow for full motion of the measured hip.3,33
FWjh_YaÊiJ[ij
The patient was supine. The hip was moved to a position of flexion, abduction, and external rotation by placing the lateral malleolus on the contralateral knee. Slight overpressure was applied to stabilize the opposite ASIS.
The effect of the movement on the patient’s symptoms was also recorded
(pain, no pain, location of pain).31,38 The examiner next assessed the Patrick’s
test in a similar manner on the involved hip. In addition to the traditional
performance of the Patrick’s test, an assessment of mobility of the involved
hip relative to the uninvolved hip (normal, hypomobile, hypermobile) was
made. After zeroing a bubble inclinometer against a wall, the range of motion was measured for each hip with the inclinometer placed approximately
2.5 cm proximal to the patient’s flexed knee.
>_f?dj[hdWbHejWj_ed
The patient was prone. The hip was maintained in neutral flexion/extension
and adduction/abduction. The knee was flexed to 90º, and the hip was
passively moved to a position of maximum internal rotation. The examiner
noted maximal internal rotation when the patient’s opposite hip/buttock
began to rise from the table. The range of motion was measured for each hip
using a bubble inclinometer placed just proximal to the lateral malleolus.12
>_f;nj[hdWbHejWj_ed
The patient was prone. The hip was maintained in neutral flexion/extension
and adduction/abduction. The opposite hip was passively placed in slight
abduction to avoid impeding motion of the tested hip. The knee was flexed
to approximately 90°, and the hip was passively moved to a position of
maximum external rotation. The examiner noted maximal external rotation
when the patient’s hip began to rise from the table. The range of motion was
measured using a bubble inclinometer placed just proximal to the lateral
malleolus.12
>_f;nj[di_ed
The patient was prone. The hip was maintained in neutral abduction/adduction and rotation. The knee was extended and the patient was instructed
to actively move his/her hip into a position of maximum extension, while
maintaining ASIS contact with the table. The examiner observed the motion making sure the patient did not contract his/her back musculature
when attempting maximum hip extension. The range of motion was measured using a universal goniometer. The fulcrum was centered over the
greater trochanter, the proximal arm along the midline of the pelvis, and
the distal arm along the midline of the femur, in line with the lateral femoral
epicondyle.3,33
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550 | september 2008 | volume 38 | number 9 | journal of orthopaedic & sports physical therapy