ArticlePDF AvailableLiterature Review

The Knee injury and Osteoarthritis Outcome Score (KOOS): From joint injury to osteoarthritis

Authors:

Abstract and Figures

The Knee injury and Osteoarthritis Outcome Score (KOOS) was developed as an extension of the WOMAC Osteoarthritis Index with the purpose of evaluating short-term and long-term symptoms and function in subjects with knee injury and osteoarthritis. The KOOS holds five separately scored subscales: Pain, other Symptoms, Function in daily living (ADL), Function in Sport and Recreation (Sport/Rec), and knee-related Quality of Life (QOL). The KOOS has been validated for several orthopaedic interventions such as anterior cruciate ligament reconstruction, meniscectomy and total knee replacement. In addition the instrument has been used to evaluate physical therapy, nutritional supplementation and glucosamine supplementation. The effect size is generally largest for the subscale QOL followed by the subscale Pain. The KOOS is a valid, reliable and responsive self-administered instrument that can be used for short-term and long-term follow-up of several types of knee injury including osteoarthritis. The measure is relatively new and further use of the instrument will add knowledge and suggest areas that need to be further explored and improved.
Content may be subject to copyright.
BioMed Central
Page 1 of 8
(page number not for citation purposes)
Health and Quality of Life Outcomes
Open Access
Review
The Knee injury and Osteoarthritis Outcome Score (KOOS): from
joint injury to osteoarthritis
EwaMRoos*
1,2
and L Stefan Lohmander
1
Address:
1
Department of Orthopaedics, Lund University Hospital, SE-221 85 Lund, Sweden and
2
Center for Research and Development, Spenshult
Hospital for Rheumatic Diseases, SE-313 92 Oskarström, Sweden
Email: Ewa M Roos* - Ewa.Roos@ort.lu.se; L Stefan Lohmander - stefan.lohmander@ort.lu.se
* Corresponding author
Abstract
The Knee injury and Osteoarthritis Outcome Score (KOOS) was developed as an extension of the
WOMAC Osteoarthritis Index with the purpose of evaluating short-term and long-term symptoms
and function in subjects with knee injury and osteoarthritis. The KOOS holds five separately scored
subscales: Pain, other Symptoms, Function in daily living (ADL), Function in Sport and Recreation
(Sport/Rec), and knee-related Quality of Life (QOL). The KOOS has been validated for several
orthopaedic interventions such as anterior cruciate ligament reconstruction, meniscectomy and
total knee replacement. In addition the instrument has been used to evaluate physical therapy,
nutritional supplementation and glucosamine supplementation. The effect size is generally largest
for the subscale QOL followed by the subscale Pain. The KOOS is a valid, reliable and responsive
self-administered instrument that can be used for short-term and long-term follow-up of several
types of knee injury including osteoarthritis. The measure is relatively new and further use of the
instrument will add knowledge and suggest areas that need to be further explored and improved.
The Knee injury and Osteoarthritis Outcome
Score (KOOS)
Why assess Health-Related Quality of Life with the Knee
Injury and Osteoarthritis Outcome Score (KOOS)?
The main reason for developing a single instrument with
the purpose of covering several types of knee injury and
including osteoarthritis (OA), was that traumatic knee
injuries often causes concomitant damage to multiple
structures (ligaments, menisci, cartilage, etc.) and fre-
quently lead to the later development of OA. To be able to
follow patients after a trauma and to gain insight into the
change of symptoms, function etc. over time, a question-
naire which covers both the short-term and long-term
consequences is needed. Prior instruments such as the
Lysholm knee scoring scale [1] have focused only on the
short-term consequences and instruments such as the
WOMAC Osteoarthritis Index [2] only on the long-term
consequences. An instrument intended for follow-up of
these patients needs to adequately monitor both the acute
injury consequences in the physically active and younger
patients, and the chronic outcome in the older.
What is the KOOS?
The KOOS is a knee-specific instrument, developed to
assess the patients' opinion about their knee and associ-
ated problems. The KOOS evaluates both short-term and
long-term consequences of knee injury. It holds 42 items
in 5 separately scored subscales; Pain, other Symptoms,
Function in daily living (ADL), Function in Sport and Rec-
reation (Sport/Rec), and knee-related Quality of Life
(QOL).
Published: 03 November 2003
Health and Quality of Life Outcomes 2003, 1:64
Received: 30 June 2003
Accepted: 03 November 2003
This article is available from: http://www.hqlo.com/content/1/1/64
© 2003 Roos and Lohmander; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permit-
ted in all media for any purpose, provided this notice is preserved along with the article's original URL.
Health and Quality of Life Outcomes 2003, 1 http://www.hqlo.com/content/1/1/64
Page 2 of 8
(page number not for citation purposes)
How was the KOOS developed?
The KOOS was originally developed in 1995 by Ewa M
Roos and colleagues at the Departments of Orthopaedics
at Lund University, Sweden and at the University of Ver-
mont, USA. Thus, the American-English and Swedish ver-
sions were developed simultaneously.
To ensure content validity for subjects with ACL injury,
meniscus injury, and early OA, we reviewed the literature,
consulted an expert panel, and conducted a pilot study
(Fig. 1). The literature indicated three principal areas of
patient-relevant outcomes: symptoms, functional status,
and satisfaction. An expert panel comprised of patients
referred to physical therapy because of knee injuries,
orthopaedic surgeons, and physical therapists from both
Sweden and the United States, was asked to identify short-
and long-term symptoms and functional disabilities
resulting from a meniscus or ACL injury. Seven factors
were identified by the panel: pain, early disease-specific
symptoms, late disease-specific symptoms (e.g. symptoms
of OA), function, quality of life, activity level, and
satisfaction.
Development and evaluation of the KOOSFigure 1
Development and evaluation of the KOOS.
Literature
review
Expert panel;
Patients,MD,PT
Pilot study
KOOS
American/English
version
Pre-testing
Reliability
Validity
Responsive-
ness
Knee
arthroscopy
TKR
Reliability
Validity
Responsive-
ness
ACL re-
construction
Pre-testing
Swedish version
Step 1.
Item generation
Step 2.
Linguistic validation
&
Cultural adaptation
Step 3.
Evaluation
Health and Quality of Life Outcomes 2003, 1 http://www.hqlo.com/content/1/1/64
Page 3 of 8
(page number not for citation purposes)
A pilot study was then conducted to identify the subjec-
tively most relevant factors among patients with post-trau-
matic osteoarthritis. Seventy-five individuals who had
had meniscus surgery 20 years previously were asked to
respond to two questionnaires, both self-administered.
The participants ranged in age from 35 to 76 (mean 56),
and showed radiological signs of knee OA, defined as
joint space narrowing and osteophytes. One of the ques-
tionnaires, by Flandry et al. [3], was constructed to assess
symptoms of anterior cruciate ligament (ACL) injury and
the other, WOMAC Osteoarthritis Index [2], for assessing
symptoms of knee OA Questions that most frequently
received high responses, and were thus considered to
reflect the most predominant symptoms, included those
relating to pain, swelling, stiffness, and the ability to run,
jump, kneel, and squat.
To be able to calculate WOMAC scores from the KOOS,
the questions from the WOMAC Osteoarthritis Index LK
3.0 [2] were included in their full and original form in the
KOOS questionnaire (with permission, Nicholas Bellamy
personal communication 1995). The KOOS dimension of
Activities of Daily Living is equivalent to that of Function
in the WOMAC Osteoarthritis Index. Questions included
in the subscales Sport and Recreational Function and
knee-related Quality of Life were adopted, in their original
form or with some modification, from other outcome
measures used to assess ACL injury [3,4]. Satisfaction and
activity level, two dimensions also considered relevant by
the panel of experts, were not included in the KOOS, since
it was not possible to agree on wording that would be
applicable for all situations.
How was the KOOS validated?
The KOOS has been validated in several different popula-
tions having surgical procedures due to knee complaints.
To ensure the instrument being valid for both short-term
and long-term consequences, validations have been car-
ried out in different populations with varying diseases and
durations and at varying ages and activity levels. Firstly,
the American-English version was validated in subjects
(age range 18–46) undergoing surgical reconstruction of
the ACL [5]. Secondly, the Swedish version was validated
in subjects (age range 16–79) undergoing knee arthros-
copy [6]. Thirdly, the KOOS was compared to the
WOMAC in subjects meniscectomized 16 years previously
(age range 38–76) with and without OA [7]. Fourthly, a
validation study was carried out in subjects (age range 43–
86) treated with total knee replacement for OA [8]. For
patients on the waiting-list for total knee replacement for
OA, content validity was assessed before surgery by asking
the patients to rate the importance of improvement in
each of the five KOOS subscales on a 5-point Likert-scale
as extremely important, very important, moderately
important, somewhat important, or not important at all.
For each subscale examples of questions within the sub-
scale were given. Over 90% reported that improvement in
the four subscales Pain, Symptoms, Activities of Daily Liv-
ing, and knee-related Quality of Life was extremely or very
important when deciding to have their knee operated on.
51% reported that improvement in functions included in
the subscale Sport and Recreation Function such as squat-
ting, kneeling, jumping, turning/twisting and running
was extremely or very important when deciding to have
their knee operated on. Postoperatively, patients tended
to start doing physical functions they did not do prior to
the operation.
Convergent and divergent construct validity was deter-
mined in comparison to the SF-36 [9], and when applica-
ble also to the Lysholm knee scoring scale [1].
What translations are available?
The KOOS has been formally validated in American-Eng-
lish [5], Swedish [6] and German [10]. Translations are
also available in Danish, Russian and Italian. Spanish,
French, Icelandic, Polish, Estonian and Greek versions are
pending.
What modifications for other joints and diseases are
available?
The KOOS has been modified to assess problems associ-
ated with the foot and ankle (FAOS) [11] and with the hip
HOOS [12]. A modification intended for evaluation of
lower extremity problems (hip, knee and foot) in subjects
with rheumatoid arthritis and other inflammatory joint
diseases (RAOS) has recently been published [13].
Symptoms experienced from the hip differs to some
extent from symptoms experiences from the knee and foot
which is reflected by differences in the symptoms subscale
of the HOOS compared to the other modifications. Swell-
ing, range of motion, and mechanical symptoms were not
included in the HOOS due to low relevance and respon-
sivenss. With regard to physical activities however there
were only minor differences between the HOOS and the
other modifications.
Why is the KOOS a good instrument to consider using?
The KOOS is a comprehensive instrument including five
subscales assessing aspects of knee injury and knee OA
considered important by patients. Most other instruments
used for acute knee injury aggregate items measuring dif-
ferent aspects into one score. This procedure flattens the
results and makes interpretation more difficult since the
included items do not always correlate. The KOOS is self-
administered and takes approximately 10 minutes to fill
out. It is a feasible instrument as illustrated by few missing
items, 0.8% for subjects having knee arthroscopy and
3.2% for subjects having total knee replacement, when
Health and Quality of Life Outcomes 2003, 1 http://www.hqlo.com/content/1/1/64
Page 4 of 8
(page number not for citation purposes)
administered by mail [6,8]. Since a subscore can be calcu-
lated when two or less items are missing for each subscale,
it was only in a few cases a subscore could not be
calculated.
Patients sustaining knee joint injury are often young and
physically active. An advantage when using the KOOS for
studies of the long-term consequences of joint injury in
such patients is that the KOOS assesses sport and recrea-
tion function and knee-related quality of life and has a
greater responsiveness compared to other more generic
instruments such as the WOMAC and the SF-36 (Fig 2).
What are the applications of the KOOS?
The KOOS is intended to be used over short and long time
intervals; to assess changes from week to week induced by
treatment (medication, surgery, physical therapy) or over
the years due to a primary knee injury, posttraumatic OA
or primary OA.
What areas of health does it measure?
The KOOS collects data on five knee-specific patient-cen-
tered outcomes: (1) pain; (2) other symptoms such as
swelling, restricted range of motion and mechanical
symptoms; (3) disability on the level of daily activities;
(4) disability on a level physically more demanding than
activities of daily living; (5) mental and social aspects
such as awareness and lifestyle changes.
Who answers it?
The KOOS is self-administered and filled out by the
patient. In the Swedish validation studies the question-
naires have been sent and returned by mail. In the Ameri-
can validation study the questionnaires were either filled
Effect sizes of KOOS, WOMAC and SF-36 six months after ACL-reconstructionFigure 2
Effect sizes of KOOS, WOMAC and SF-36 six months after ACL-reconstruction. Comparison of effect sizes of
KOOS, WOMAC and SF-36 six months after surgical reconstruction of the ruptured anterior cruciate ligament. Effect size was
defined as mean score change divided by the pre-operative standard deviation. The data are previously published (n = 21, mean
age 32 years) [5]. Placebo or sham treatment results have not been subtracted to generate effect sizes. It should be noted that
the effect size displayed here will be influenced by the preoperative within-group variation of the score dimension measured.
0
0.5
1
1.5
2
P
a
i
n
S
y
m
p
to
m
s
A
D
L
S
p
o
r
t/
R
e
c
Q
O
L
KOOS
WOMAC
SF-36
Effect size
Health and Quality of Life Outcomes 2003, 1 http://www.hqlo.com/content/1/1/64
Page 5 of 8
(page number not for citation purposes)
out prior to a doctors visit or by mail. No interview or
phone formats are available.
How long does it take to complete the KOOS?
The KOOS takes about 10 minutes to fill out.
How is the KOOS administered?
The KOOS is self-explanatory and can be administered in
the waiting room or used as a mailed survey.
How is the KOOS scored?
The five patient-relevant subscales of KOOS are scored
separately: Pain (nine items); Symptoms (seven items);
ADL Function (17 items); Sport and Recreation Function
(five items); Quality of Life (four items). A Likert scale is
used and all items have five possible answer options
scored from 0 (No Problems) to 4 (Extreme Problems)
and each of the five scores is calculated as the sum of the
items included. Scores are transformed to a 0–100 scale,
with zero representing extreme knee problems and 100
representing no knee problems as common in orthopae-
dic assessment scales and generic measures. Scores
between 0 and 100 represent the percentage of total pos-
sible score achieved. An aggregate score is not calculated
since it is regarded desirable to analyze and interpret the
five dimensions separately.
Is there automated administration or scoring software?
Scoring software is available in Microsoft Excel-format
and can be downloaded from http://www.koos.nu
How are the KOOS scores interpreted?
The score is a percentage score from 0 to 100, 0 represent-
ing extreme problems and 100 representing no problems.
This direction, 100 indicating no problems, is common in
orthopaedic instruments and generic measures like the SF-
36. In measures developed by rheumatologists, like the
WOMAC, 100 usually represents worst possible result.
Is the KOOS responsive to change?
Change over time
The effect sizes following surgical procedures vary both
with regard to the procedure being undertaken and the
specific KOOS subscale. Generally, the subscale QOL is
the most responsive, followed by the subscale Pain. The
highest effect sizes observed were obtained after total knee
replacement (Figure 3).
Between-group differences
Several randomized trials using the KOOS have been pub-
lished. In a trial comparing two methods of reconstruc-
tion of the ACL, significant differences between groups
were found in ADL, Sport/Rec and QOL at various postop-
erative time points [14]. In a trial of glucosamine supple-
mentation, significant group differences were found in
Pain and ADL [15]. In a trial of a nutritional supplement
significant between-group differences were found for ADL
[16]. In all trials, significant improvement was detected in
the treatment groups over time. The number of subjects in
each treatment arm in these RCT:s ranged from 15 to 27.
In a study on continuous passive motion as supplemental
treatment following total knee replacement, no signifi-
cant differences were found between groups [17].
What is the meaningful change for the instrument?
The minimal perceptible clinical improvement (MPCI)
represents the difference on the measurement scale asso-
ciated with the smallest change in the health status detect-
able by the patient. The MPCI of the KOOS has not been
formally assessed. Since the KOOS questionnaire contains
the full and original version of the WOMAC index and
WOMAC scores can easily be calculated, the MPCI of
approximately 10 obtained for the WOMAC [18] has been
applied to KOOS in power analyses and when determin-
ing cut-offs for improvement and deterioration (Parad-
owski P et al., personal communication 2003).
Accordingly, a level of 10 points or more of improvement
or decline was suggested as a cut-off representing a clini-
cally significant difference.
In support of this suggestion, we compared KOOS data
after ACL reconstruction with the clinical knowledge of
rehabilitation phases following ACL reconstruction. Three
months postoperatively, the patients experienced some
pain, swelling and restriction in range of motion and had
not pushed their knee during sporting activities. This was
reflected by (statistically non-significant) changes of 1 to
7 KOOS score points in pain, symptoms, and sport and
recreation function over this time interval, compared to
preoperative scores. Six months postoperatively, the
patients were back at more vigorous activities including
sport and had few symptoms, reflected by (statistically sig-
nificant) changes of 8–23 score points in all subscale
scores. Thus, it seems that a change in score of 8 points or
more may represent a clinically significant change follow-
ing ACL reconstruction. We thus suggest that 8–10 points
may represent the minimal perceptible clinical improve-
ment (MPCI) of the KOOS. However, to further explore
this difficult question, additional studies including differ-
ent treatments and patient groups should be undertaken.
Has the KOOS been used in individual patients?
The test-retest reliability has been sufficient for most sub-
scales in most studies to allow assessment of change over
time in individual patients. The KOOS is frequently used
in the clinic to help patients and therapists follow the
progress after interventions due to knee problems.
Health and Quality of Life Outcomes 2003, 1 http://www.hqlo.com/content/1/1/64
Page 6 of 8
(page number not for citation purposes)
In which populations has the KOOS been used?
The KOOS is intended to be used in knee injury that can
result in post traumatic OA or in primary OA. The KOOS
has been used in men and women ranging from 14–79
years in age with varying disorders resulting in knee com-
plaints such as anterior cruciate ligament tear, meniscus
tear, and mild, moderate and severe OA. The KOOS has
been used to follow the immediate post-operative period
and in 10 to 20 year follow-ups of knee injury. The KOOS
was published in 1998, and in prospective studies of knee
injury no longer follow-ups than 2 years have been pub-
lished to date. The KOOS has also been used in healthy
female soccer players [19]. By others, the KOOS has been
used to assess the effects of anterior cruciate ligament
Effect size for different surgical interventions measured by KOOSFigure 3
Effect size for different surgical interventions measured by KOOS. KOOS effect sizes 6 months following surgical
knee interventions. Effect size was defined as mean score change divided by the pre-operative standard deviation. The data
from total knee replacement [8] (n = 105, mean age 71.3 years) and anterior cruciate ligament reconstruction [5] (n = 21,
mean age 32 years) are previously published. The data from tibial osteotomy concerns 50 patients (mean age 54 years) under-
going hemicallotasis osteotomy (W-Dahl A, Lund University, personal communication 2001). The data from cartilage repair
concerns 50 patients (mean age 34 years) undergoing autologus cartilage transplant (Olsson M, University of Gothenburg, per-
sonal communication 2002). The data for meniscectomy concern 66 patients (mean age 44 years) undergoing arthroscopic par-
tial meniscectomy (Roos E, Lund University, personal communication 2003). Placebo or sham treatment results have not been
subtracted to generate effect sizes. It should be noted that the effect size displayed here will be influenced by the preoperative
within-group variation of the score dimension measured. This may vary between the different study groups. All data are pub-
lished with permission from the authors.
-0.5
0
0.5
1
1.5
2
2.5
3
Pain
Symptoms
ADL
Sport/Rec
QOL
Effect size
A
r
t
h
r
o
p
l
a
s
t
y
T
i
b
i
a
l
O
s
t
e
o
t
o
m
y
A
C
L
-
r
e
c
o
n
s
t
r
u
c
t
i
o
n
M
e
n
i
s
c
e
c
t
o
m
y
A
u
t
o
l
o
g
o
u
s
C
a
r
t
i
l
a
g
e
T
r
a
n
s
p
l
a
n
t
a
t
i
o
n
Health and Quality of Life Outcomes 2003, 1 http://www.hqlo.com/content/1/1/64
Page 7 of 8
(page number not for citation purposes)
reconstruction [14], glucosamine supplementation [15],
and nutritional supplementation [16].
Do we need permission to use it?
Permission is not required to use the KOOS.
Who may I contact to obtain a copy of the KOOS?
The KOOS questionnaire including modifications for the
foot and ankle (FAOS), hip (HOOS) and rheumatoid and
other types of arthritis (RAOS) can be downloaded from
http://www.koos.nu
How can we obtain more information about the KOOS?
Please go to http://www.koos.nu
How much does it cost to purchase the KOOS itself?
The KOOS is free of charge.
How can we obtain a scientific support during our study?
Information is available at http://www.koos.nu
Discussion
The KOOS was first published in 1998, and is thus a rela-
tively new instrument. Its use in several different patient
groups is supported by the currently available literature.
However, further use of the instrument will add knowl-
edge and suggest areas that need to be further explored
and improved.
KOOS vs. WOMAC
The KOOS was developed as an extension of the WOMAC
Osteoarthritis Index with the overall purpose to evaluate
short- and long-term symptoms and function after knee
injury and OA. The reason for developing one instrument
covering several types of knee injury and OA was that
these structural damages often coincide within patients.
All the questions of the WOMAC LK 3.0 were retained so
that a WOMAC score might be calculated separately and
compared with the KOOS score. This would also facilitate
comparison of outcomes with previous studies using
WOMAC on other patient populations.
Knee injury most often includes damage to the ligaments,
the menisci, or the cartilage. These injuries can be isolated
but are frequently combined, and often result in the later
development of OA. About 10–15 years after an injury to
the menisci or anterior cruciate ligament, approximately
every other patient has developed radiographic OA [20–
23]. To increase sensitivity for patients with knee injury,
items were added to the WOMAC pain and stiffness sec-
tions and two new subscales were added, resulting in a 42
item questionnaire with five subscales; Pain (9 items),
Other symptoms (7 items), ADL Function (17 items),
Sport and Recreation Function (5 items), and knee-related
Quality of Life (4 items).
As expected, larger effect sizes of the KOOS compared to
the WOMAC was found in younger subjects (age 18–46)
with knee injury [5]. Increased sensitivity of the KOOS
compared with the WOMAC was also shown in previ-
ously meniscectomized subjects with and without radio-
graphic knee OA aged 38–76 [7]. However, a more
unexpected finding was that larger effect sizes were found
for the KOOS compared to the WOMAC in elderly sub-
jects (age 43–86) treated with a total knee replacement
because of severe knee OA [8]. Increased sensitivity may
yield larger score changes over time, resulting in larger
effect sizes. This in turn may allow smaller patient study
groups when comparing treatments.
Conclusions
KOOS was developed as an extension of the WOMAC
Osteoarthritis Index with the purpose of evaluating short-
and long-term symptoms and function in young and
physically active subjects with knee injury and OA. The
questions of the WOMAC LK 3.0 were retained so that a
WOMAC score might be calculated separately and com-
pared with the KOOS score. As expected, larger effect sizes
for KOOS as compared with WOMAC were shown for
young subjects with knee injury. The use of KOOS with
different patient groups is supported by the available liter-
ature. However, further use of the instrument will suggest
areas that need to be further improved.
Authors' contributions
ER drafted the manuscript. SL contributed significantly to
the manuscript. Both authors read and approved the final
manuscript.
References
1. Tegner Y and Lysholm J: Rating systems in the evaluation of
knee ligament injuries. Clin Orthop 1985:43-49.
2. Bellamy N, Buchanan WW, Goldsmith CH, Campbell J and Stitt LW:
Validation study of WOMAC: a health status instrument for
measuring clinically important patient relevant outcomes to
antirheumatic drug therapy in patients with osteoarthritis of
the hip or knee. J Rheumatol 1988, 15:1833-1840.
3. Flandry F, Hunt JP, Terry GC and Hughston JC: Analysis of subjec-
tive knee complaints using visual analog scales. Am J Sports Med
1991, 19:112-118.
4. Mohtadi N: Development and validation of the quality of life
outcome measure (questionnaire) for chronic anterior cru-
ciate ligament deficiency. Am J Sports Med 1998, 26:350-359.
5. Roos EM, Roos HP, Lohmander LS, Ekdahl C and Beynnon BD: Knee
Injury and Osteoarthritis Outcome Score (KOOS)--develop-
ment of a self-administered outcome measure. J Orthop Sports
Phys Ther 1998, 28:88-96.
6. Roos EM, Roos HP, Ekdahl C and Lohmander LS: Knee injury and
Osteoarthritis Outcome Score (KOOS)--validation of a
Swedish version. Scand J Med Sci Sports 1998, 8:439-448.
7. Roos EM, Roos HP and Lohmander LS: WOMAC Osteoarthritis
Index--additional dimensions for use in subjects with post-
traumatic osteoarthritis of the knee. Western Ontario and
MacMaster Universities. Osteoarthritis Cartilage 1999, 7:216-221.
8. Roos EM and Toksvig-Larsen S: Knee injury and Osteoarthritis
Outcome Score (KOOS) - validation and comparison to the
WOMAC in total knee replacement. Health Qual Life Outcomes
2003, 1:17.
Publish with BioMed Central and every
scientist can read your work free of charge
"BioMed Central will be the most significant development for
disseminating the results of biomedical research in our lifetime."
Sir Paul Nurse, Cancer Research UK
Your research papers will be:
available free of charge to the entire biomedical community
peer reviewed and published immediately upon acceptance
cited in PubMed and archived on PubMed Central
yours — you keep the copyright
Submit your manuscript here:
http://www.biomedcentral.com/info/publishing_adv.asp
BioMedcentral
Health and Quality of Life Outcomes 2003, 1 http://www.hqlo.com/content/1/1/64
Page 8 of 8
(page number not for citation purposes)
9. Ware J. E., Jr. and Sherbourne CD: The MOS 36-item short-form
health survey (SF-36). I. Conceptual framework and item
selection. Med Care 1992, 30:473-483.
10. Kessler S, Lang S, Puhl W and Stove J: [The knee injury and oste-
oarthritis outcome score - a multifunctional questionnaire
to measure outcome in knee arthroplasty]. Z Orthop Ihre
Grenzgeb 2003, 141:277-282.
11. Roos EM, Brandsson S and Karlsson J: Validation of the foot and
ankle outcome score for ankle ligament reconstruction. Foot
Ankle Int 2001, 22:788-794.
12. Nilsdotter AK, Lohmander SL, Klassbo M and Roos EM: Hip Disabil-
ity and Osteoarthritis Outcome Score (HOOS) - Validity
and responsiveness in total hip replacement. BMC Musculoske-
let Disord 2003, 4:10.
13. Bremander AB, Petersson IF and Roos EM: Validation of the Rheu-
matoid and Arthritis Outcome Score (RAOS) for the lower
extremity. Health Qual Life Outcomes 2003, 1:55.
14. Nau T, Lavoie P and Duval N: A new generation of artificial lig-
aments in reconstruction of the anterior cruciate ligament.
Two-year follow-up of a randomised trial. J Bone Joint Surg Br
2002, 84:356-360.
15. Braham R, Dawson B and Goodman C: The effect of glucosamine
supplementation on people experiencing regular knee pain.
Br J Sports Med 2003, 37:45-49.
16. Colker CM, Swain M, Lynch L and Gingerich DA: Effects of a milk-
based bioactive micronutrient beverage on pain symptoms
and activity of adults with osteoarthritis: a double-blind, pla-
cebo-controlled clinical evaluation. Nutrition 2002, 18:388-392.
17. Ask S, Lindmark B and Johansson A: [Evaluation of the use of con-
tinuous passive motion (CPM) in rehabilitation following
total knee replacement]. Nordisk Fysioterapi 2003, 7:29-39.
18. Ehrich EW, Davies GM, Watson DJ, Bolognese JA, Seidenberg BC and
Bellamy N: Minimal perceptible clinical improvement with the
Western Ontario and McMaster Universities osteoarthritis
index questionnaire and global assessments in patients with
osteoarthritis. J Rheumatol 2000, 27:2635-2641.
19. Ostenberg A, Roos E, Ekdahl C and Roos H: Physical capacity in
female soccer players -does age make a difference? Advances
in Physiotherapy 2000, 2:39-48.
20. Roos H, Lauren M, Adalberth T, Roos EM, Jonsson K and Lohmander
LS: Knee osteoarthritis after meniscectomy: prevalence of
radiographic changes after twenty-one years, compared
with matched controls. Arthritis Rheum 1998, 41:687-693.
21. Lohmander LS and Roos H: Knee ligament injury, surgery and
osteoarthrosis. Truth or consequences? Acta Orthop Scand 1994,
65:605-609.
22. Englund M, Roos EM and Lohmander LS: Impact of type of menis-
cal tear on radiographic and symptomatic knee osteoarthri-
tis: a sixteen-year followup of meniscectomy with matched
controls. Arthritis Rheum 2003, 48:2178-2187.
23. von Porat A, Roos EM and Roos H: High prevalence of osteoar-
thritis 14 years after an anterior cruciate ligament tear in
male soccer players - A study of radiographic and patient-
relevant outcomes. Ann Rheum Dis 2003, In press:.
... A total score has not been validated and is not recommended. Scores are then converted to a 0-100 scale (percentage of total possible score obtained), where 0 represents extreme knee problems and 100 represents no knee problems (32). This questionnaire was completed by those who reported knee pain and established cut-off score of ≤86 for any of the domains is used to classify individuals with symptomatic knees (33). ...
... Our recent systematic review on the existing clinical trials concluded that both GSM lipid extract or whole meat powder products provide a clinically meaningful improvement in VAS pain for OA symptoms (44). In terms of knee related symptoms, the GSM group showed a greater improvement in KOOS symptoms domain overtime, although the change was not significant and did not reach the suggested minimal clinical improvement (at least eight points improvement) (32). ...
Full-text available
Article
Objective To investigate the effect of whole greenshell mussel (GSM) powder on biomarkers of cartilage metabolism, inflammatory cytokines, and joint symptoms in postmenopausal women with overweight/obesity and joint discomfort.DesignFifty-five postmenopausal women with overweight/obesity were randomly assigned to receive 3 g/day whole GSM powder or placebo for 12 weeks. Cartilage turnover biomarkers urinary C-telopeptide of type II collagen (CTX-II) and serum cartilage oligomeric matrix protein (COMP) were measured at baseline, week 6 and 12. Plasma cytokines were measured at baseline and week 12. Joint pain and knee-related problems were assessed at baseline and week 12 using a 100 mm Visual Analogue Scale (VAS) and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire, respectively.ResultsForty-nine participants completed the study (GSM n = 25, placebo n = 24). After 12 weeks, urinary CTX-II showed no significant change over time or between the groups (interaction effect P = 0.1). However, in women with symptomatic knees, a significant difference was noted between the group (treatment effect P = 0.04), as it was lower in the GSM group compared to placebo group at week 6 (P = 0.04) and week 12 (P = 0.03). Serum COMP and plasma cytokines were not affected. GSM supplementation showed greater reduction in the VAS pain score than placebo (−13.2 ± 20.3 vs. −2.9 ± 15.9; P = 0.04). No significant change in KOOS domains between the two groups was observed.Conclusion Oral supplementation of whole GSM powder at 3 g/day may slow down the degradation of type II collagen in postmenopausal women with symptomatic knees. GSM treatment conferred clinical benefit on overall joint pain. No significant effect was noted for inflammatory cytokines, suggesting that GSM may act within the joint microenvironment rather than at the systemic level.Clinical trial registration[www.australianclinicaltrials.gov.au/clinical-trialregistries], identifier [ACTRN12620000413921p].
... A prospective study of patients undergoing cartilage repair with microfracture fracture and BST-CarGel [Smith and Nephew, Watford, England] at our institution from 2016 to 2019 was performed. Clinical outcomes were determined using two clinically validated patient-reported questionnaires: Lysholm Knee Scoring System 7 and Knee Injury and Osteoarthritis Outcome Score (KOOS) 8 . These questionnaires were administered before surgery and at a minimum of two years after surgery. ...
... Reference values for KL grading scale [83] and the statistical distributions of KL scores of HKOA patients in our dataset are shown in Figure 6. Patients with OA completed the HOOS or KOOS to assess self-reported functioning [17,18]. Table 2 presents the list of HOOS and KOOS pain-related questions. ...
Full-text available
Article
Joint pain is a prominent symptom of Hip and Knee Osteoarthritis (OA), impairing patients’ movements and affecting the joint mechanics of walking. Self-report questionnaires are currently the gold standard for Hip OA and Knee OA pain assessment, presenting several problems, including the fact that older individuals often fail to provide accurate self-pain reports. Passive methods to assess pain are desirable. This study aims to explore the feasibility of OA-Pain-Sense, a passive, automatic Machine Learning-based approach that predicts patients’ self-reported pain levels using SpatioTemporal Gait features extracted from the accelerometer signal gathered from an anterior-posterior wearable sensor. To mitigate inter-subject variability, we investigated two types of data rescaling: subject-level and dataset-level. We explored six different binary machine learning classification models for discriminating pain in patients with Hip OA or Knee OA from healthy controls. In rigorous evaluation, OA-Pain-Sense achieved an average accuracy of 86.79% using the Decision Tree and 83.57% using Support Vector Machine classifiers for distinguishing Hip OA and Knee OA patients from healthy subjects, respectively. Our results demonstrate that OA-Pain-Sense is feasible, paving the way for the development of a pain assessment algorithm that can support clinical decision-making and be used on any wearable device, such as smartphones.
... In cases where email contact was not possible, patients filled out the questionnaire over a telephone interview. The survey itself consisted of relevant questions extracted from the KOOS (Knee Injury and Osteoarthritis Outcome Score [21]. ...
Full-text available
Article
Purpose Joint dynamics following Total Knee Arthroplasty (TKA) may influence patient-reported outcome. Simulations allow many knee alignment approaches to a single patient to be considered prior to surgery. The simulated kinematics can be matched to patient-reported outcome to predict kinematic patterns most likely to give the best outcome. This study aims to validate one such previously developed algorithm based on a simulated deep knee bend (the Dynamic Knee Score, DKS). Methods 1074 TKA patients with pre- and post-operative Computerised Tomography (CT) scans and 12-month post-operative Knee Injury and Osteoarthritis Outcomes (KOOS) Scores were identified from the 360 Med Care Joint Registry. Landmarking and registration of implant position was performed on all CT scans, and each of the achieved TKAs was computationally simulated and received a predictive outcome score from the DKS. In addition, a set of potential alternative surgical plans which might have been followed were simulated. Comparison of patient-reported issues and DKS score was evaluated in a counter-factual study design. Results Patient-reported impairment with the knee catching and squatting was shown to be 30% lower ( p = 0.005) and 22% lower ( p = 0.026) in patients where the best possible DKS result was the one surgically achieved. Similar findings were found relating attainment of the best tibial slope and posterior femoral resection DKS plans to patient-reported difficulty straightening the knee (40% less likely, p < 0.001) and descending stairs (35% less likely, p = 0.006). Conclusion The DKS has been shown to correlate with presence of patient-reported impairments post-TKA and the resultant algorithm can be applied in a pre-operative planning setting. Outcome optimization in the future may come from patient-specific selection of an alignment strategy and simulations may be a technological enabler of this trend. Level of evidence III (Retrospective Cohort Study).
Article
Falls represent an important adverse effect associated with knee osteoarthritis and result in a significant financial burden on the healthcare system. Therefore, identification of fall predictors is essential to minimize fall incidence. However, few studies have investigated falls and fall predictors, particularly focused on the fear of falls and proprioception. In this study, we investigated significant fall predictors in patients with knee osteoarthritis in Malang, Indonesia. Our findings may serve as useful guidelines to develop geriatric fall prevention programs. This cross-sectional survey using purposive sampling was performed between April and July 2021 and included 372 participants. We recorded the following data: sociodemographic and medical history questionnaire responses, visual analog scale scores, Hopkins falls grading scale scores, Fall Efficacy Scale-International scores, proprioception test findings, knee injury and osteoarthritis outcome score (KOOS), range of motion (ROM), chair stand test and the timed up and go test performance. Data were analyzed using the chi-square and t tests, and multivariate logistic regression to determine significant fall predictors. Multivariate logistic regression analysis showed a lower risk of falls in patients with better proprioception and ROM than in the other groups (odds ratio 0.55 vs 0.96). The risk of falls was higher in patients with higher KOOS symptoms, fear of falls, diagnosis of low back pain and diabetes mellitus, and increased body mass index than in the other groups (odds ratio 1.41, 2.65, 1.27, 3.45, and 1.10, respectively. Our study shows that knee proprioception and ROM serve as protective factors against falls, whereas KOOS symptoms, fear of falls, low back pain, diabetes mellitus, and body mass index were associated with a high risk of falls, with diabetes mellitus and fear of falls being the most significant risk factors. These findings may be useful to policy makers to develop a fall prevention program that can be implemented in community health care centers across Indonesia to deliver individualized, person-centered care and improve fall prevention strategies through a systematic process comprising evaluation, intervention, and monitoring to minimize fall risk.
Article
Despite increased pressure to capture patient-reported outcome measures for at least 1 year following total joint arthroplasty (TJA), follow-up rates during the first year after TJA are typically lower than desired and may result in biased findings if data are not missing at random. We conducted a retrospective review of medical records of primary total knee arthroplasty patients treated by a single surgeon at an urban academic private hospital. Main measures were demographics (sex, age, race, and insurance), body mass index, travel distance to clinic, and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Multivariable regression analyses were performed to identify patient characteristics associated with attendance at follow-up visits and predictors of attendance at 6-month follow-up. Among the 205 study patients, follow-up visit attendance declined from a high of 95.7% at day 14 to lows of 69.2% at 6 months and 64.4% at 1 year. Attendance at the previously scheduled follow-up visit was a statistically significant predictor of attendance at 3-month (P=.0015), 6-month (P=.0002), and 1-year (P<.0001) follow-up visits, and travel distance was significantly associated with attending the 1-year follow-up visit (P=.042). Patients with the most favorable KOOS Symptom, Pain, and Function in daily living subscale scores at 3-month follow-up were significantly less likely to attend the 6-month follow-up visit than patients with the least favorable KOOS scores. Prospective studies are needed to identify the full range of factors that may contribute to high rates of loss to follow-up after TJA, which should be of concern to researchers, clinicians, and hospitals. [Orthopedics. 20XX;XX(X):xx-xx.].
Article
Background Psychological patient-reported outcomes (PROs) are recommended for use in test batteries to aid in decision-making, regarding whether patients are well prepared to return to sports (RTS) after anterior cruciate ligament (ACL) reconstruction. However, the values that should be regarded as “pass” or “fail” are still unclear. Purpose This study aimed to identify cut-off values for three commonly used psychological PROs that could differentiate patients who suffer a second ACL injury from patients who do not within two years of RTS in patients after ACL reconstruction with respect to recovery of symmetrical quadriceps strength. Study design Diagnostic/prognostic study Methods Demographic data, isokinetic strength test data for quadriceps, as well as results for the ACL-Return to Sport after Injury scale (ACL-RSI), Knee Injury and Osteoarthritis Outcome Score (KOOS) Quality of Life, and Function in Sport and Recreation sub-scales, and the 18-item version of the Knee Self-Efficacy Scale (K-SES 18 ) were extracted from a registry. Receiver operating characteristic (ROC) curves were calculated for each PRO. Accuracy of the cut-offs was presented with two summary measures for the ROC: the area under the curve (AUC) and Youden index. Results In total, 641 (355 men, 61%) patients (24.8 [SD 7.6] year old at ACL reconstruction) were included. The cut-off values were not able to differentiate patients who suffered a second ACL injury up to 24 months after RTS and ACL reconstruction from patients who did not. Additionally, achieving symmetrical quadriceps strength did not improve the cut-off psychometric properties. Conclusion Since cut-off values could not differentiate between patients who suffered a second ACL injury and those who did not, clinicians should not rely only on cut-off values or a single PRO of those analyzed in this study when making decisions on which patients are at risk of experiencing a second ACL injury when returning to sports after ACL reconstruction. Level of Evidence Level 3
Full-text available
Article
Objectives The main objective was to investigate 5-year outcomes in patients with knee osteoarthritis, randomised to one of two non-surgical treatments. Setting Two outpatient clinics. Participants At baseline, 100 patients with radiographic and symptomatic knee osteoarthritis not found eligible for knee replacement (KR) were included. Main exclusion criteria were average score above 75 of the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales pain, symptoms, function of daily living and quality of life; KOOS 4 and average knee pain the previous week greater than 60 mm on a 100 mm visual analogue scale. Interventions Patients were randomised to supervised non-surgical treatment consisting of patient education, supervised exercise, weight loss, insoles, and pain medication (the MEDIC treatment) or written advice. The 12-week MEDIC treatment included patient education, neuromuscular exercise, insoles and a dietary weight loss programme and/or pain medication if needed and written advice consisted of two leaflets. Primary and secondary outcome measures Primary outcome was 5-year mean change for KOOS 4 . Secondary outcomes included KOOS subscales, self-reported health, usage of pain medication and self-reported physical activity. Results Thirty-nine (78%) and 36 (72%) from the MEDIC and written advice groups responded at 5 years. There were no between-group differences in KOOS 4 (difference 5.3 (95% CI −1.5 to 12.1) or any secondary outcomes. However, the 95% CI included the minimal clinically important difference for the main outcome. Seventy-six percent of the MEDIC group and 66% of the written advice group experienced clinically important improvements in KOOS 4 . Fifteen patients (30%) from the MEDIC group and 17 (34%) from the written advice group received KR in the index knee. Undergoing KR did not result in a statistically significant greater improvement in KOOS 4 (difference 6.1 (95% CI −1.1 to 13.4). Conclusions No statistically significant differences between supervised non-surgical treatment and written advice were demonstrated at 5 years. Most patients experienced clinically important improvements, irrespective of initial treatment strategy or KR. Trial registration number NCT01535001 ; ClinicalTrials.gov.
Article
This Position Statement is an update to the existing statement. It is intended for all health practitioners who manage people with hip/knee osteoarthritis (OA). It synthesises the most recent evidence (with a focus on clinical guidelines and systematic reviews) for exercise in people with hip/knee OA, and provides guidance to practitioners about how best to implement exercise in clinical practice. Clinical practice guidelines for hip/knee OA advocate physical activity and exercise as fundamental core components of evidence-based management. Research evidence indicates that exercise can reduce joint pain, increase physical function, and improve quality of life in hip/knee OA, and that a range of exercise types (both supervised and unsupervised) may be beneficial. Exercise dosage should be guided by the principles of the American College of Sports Medicine. As people with OA experience many barriers to exercise, practitioners should take an active role in monitoring and promoting adherence to exercise in order to optimise therapeutic benefits.
Full-text available
Article
A 36-item short-form (SF-36) was constructed to survey health status in the Medical Outcomes Study. The SF-36 was designed for use in clinical practice and research, health policy evaluations, and general population surveys. The SF-36 includes one multi-item scale that assesses eight health concepts: 1) limitations in physical activities because of health problems; 2) limitations in social activities because of physical or emotional problems; 3) limitations in usual role activities because of physical health problems; 4) bodily pain; 5) general mental health (psychological distress and well-being); 6) limitations in usual role activities because of emotional problems; 7) vitality (energy and fatigue); and 8) general health perceptions. The survey was constructed for self-administration by persons 14 years of age and older, and for administration by a trained interviewer in person or by telephone. The history of the development of the SF-36, the origin of specific items, and the logic underlying their selection are summarized. The content and features of the SF-36 are compared with the 20-item Medical Outcomes Study short-form.
Full-text available
Article
A 36-item short-form (SF-36) was constructed to survey health status in the Medical Outcomes Study. The SF-36 was designed for use in clinical practice and research, health policy evaluations, and general population surveys. The SF-36 includes one multi-item scale that assesses eight health concepts: 1) limitations in physical activities because of health problems; 2) limitations in social activities because of physical or emotional problems; 3) limitations in usual role activities because of physical health problems; 4) bodily pain; 5) general mental health (psychological distress and well-being); 6) limitations in usual role activities because of emotional problems; 7) vitality (energy and fatigue); and 8) general health perceptions. The survey was constructed for self-administration by persons 14 years of age and older, and for administration by a trained interviewer in person or by telephone. The history of the development of the SF-36, the origin of specific items, and the logic underlying their selection are summarized. The content and features of the SF-36 are compared with the 20-item Medical Outcomes Study short-form.
Full-text available
Article
A questionnaire using a system of visual analog scales was developed for analyzing subjective knee com plaints. This system was tested on 117 consecutive patients who had undergone knee surgery and 65 patients at their initial office evaluation of a knee disor der. The validity of and patient affinity for this type of questionnaire was compared with that of three other established subjective evaluation methods. The visual analog scale system was shown to be valid and comparable to other methods while offering several advantages. It brought greater sensitivity and greater statistical power to data collection and analysis by allowing a broader range of responses than did traditional categorical responses. It removed bias that was introduced by examiner questioning, and it allowed graphic temporal comparisons. Most importantly, pa tient affinity was higher for this type of subjective evaluation than for other methods.
Full-text available
Article
Many different methods of evaluating disability after knee ligament injury exist. Most of them differ in design. Some are based on only patients' symptoms. Other include patients' symptoms, activity grading, performance in a test, and clinical findings. The rating in these evaluating systems can be either numerical, as in a score, or binary, with yes/no answers. Comparison between a symptom-related score and a score of more complex design showed that the symptom-related score gave a more differentiated picture of the disability. It was also shown that the binary rating system gave less detailed information than a score and that differences in a binary rating can depend on at what level the symptoms are regarded as "significant." A new activity grading scale, where work and sport activities were graded numerically, was constructed as complement to the functional score. When evaluating knee ligament injuries, stability testing, functional knee score, performance test, and activity grading are all important. However, the relative importance varies during the course of treatment, and therefore they should not all be included in one and the same score.
Full-text available
Article
We reviewed reports that describe development of osteoarthrosis of the knee after anterior cruciate ligament or meniscus injury. The occurrence of posttraumatic osteoarthrosis varied considerably from one report to another. The literature does not lend support to the efficacy of cruciate ligament repair or reconstruction in retarding the progression of osteoarthrosis after knee injury. We encourage prospective, controlled, randomized and masked studies that aim to evaluate the utility of ligament reconstruction, meniscus suture or meniscus transplantation for preventing posttraumatic osteoarthrosis.
Article
There is an increased risk of injuries, especially knee injuries, in young female soccer players. If age-related differences in physical capacity could be identified, the possibilities for injury prevention may increase. The objective was to study possible age-related differences in isokinetic muscle strength, aerobic capacity, functional performance, and general joint laxity in female soccer players. Body mass index (BMI) (kg × m-2) was also measured. In total 108 players, recruited from seven soccer teams, were tested. The mean age was 20.2 years (SD=4.1, range=14-30). Players aged 20 years and>20 years were compared. The following tests were employed: isokinetic knee extensor and flexor strength at velocities of 60 °/s and 180°/s, one-leg hop, triple jump, vertical jump, square-hop, and aerobic capacity. The older group had greater isokinetic strength for the flexor muscles at a peak torque of 60°/s (p=0.04), and total work at 60°/s and 180°/s (p=0.04 and 0.03). The older group had a higher BMI and more years of soccer playing (p0.001). The results revealed no significant differences between the age groups regarding, functional performance, aerobic capacity, or general joint laxity. Further studies are needed on intrinsic risk factors to identify variables explaining the difference in injury rate between younger and older players.
Article
SummaryVariable use is made of continuous passive motion (CPM) as a modality in rehabilitation after total knee replacement. The literature regarding the value of using CPM in addition to exercise is reviewed. The claimed beneficial effects of CPM on reducing pain, helping wound healing, maintaining circulation, gaining range of motion, reducing length of hospital stay and reducing the need for manipulation under anaesthetic are discussed. Perceived disadvantages of CPM including cost and the development of extension lag are also considered, as is the issue of optimal duration of application of CPM. The results of the studies are inconclusive, but several trends are identified and their implications for rehabilitation discussed.
Article
Within the context of a double blind randomized controlled parallel trial of 2 nonsteroidal antiinflammatory drugs, we validated WOMAC, a new multidimensional, self-administered health status instrument for patients with osteoarthritis of the hip or knee. The pain, stiffness and physical function subscales fulfil conventional criteria for face, content and construct validity, reliability, responsiveness and relative efficiency. WOMAC is a disease-specific purpose built high performance instrument for evaluative research in osteoarthritis clinical trials.
Article
To study the long-term outcome of surgical removal of a meniscus in the knee with regard to radiographic signs of osteoarthritis (OA). Of the 123 patients who underwent an open meniscectomy due to an isolated meniscus tear in 1973 at Lund University Hospital, 107 were followed up 21 years later by clinical examination and by review of knee radiographs obtained with weight bearing. Seventy-nine of the 107 patients were men, and the mean age of the total study group at examination was 55 years (range 35-77). Sixty-eight sex- and age-matched individuals with healthy knees served as controls. Mild radiographic changes were found in 76 (71%) of the knees, while more advanced changes, comparable with a Kellgren-Lawrence grade of 2 or higher, were seen in 51 (48%). The corresponding prevalence values in the control group were 12 (18%) and 5 (7%), respectively. The relative risk for the presence of the more advanced radiographic changes representing definite radiographic tibiofemoral OA was 14.0 (95% confidence interval 3.5-121.2), using age- and sex-matched pairs for comparison. No correlation with sex, localization to compartment, type of meniscus tear, or work load was found. Knee symptoms were reported twice as often in the study group as in the controls. Surgical removal of a meniscus following knee injury represents a significant risk factor for radiographic tibiofemoral OA, with a relative risk of 14.0 after 21 years.
Article
A patient-based, subjective outcome measure for chronic anterior cruciate ligament deficiency was developed, pretested, and validated. The development of the outcome measure was completed in four stages: 1) item generation (167 items), 2) item reduction (by surveying 79 patients), 3) questionnaire formation and pretesting (20 patients), and 4) reliability, responsiveness, and validity assessment (100 patients). This disease-specific quality of life measure is a 32-item questionnaire using a 100-mm visual analog scale response format. Face validity was derived from extensive direct patient input. Content validity was determined by consensus among 20 knee surgeons. There was no significant difference on test-retest reliability, with an overall average error of 6%. The outcome measure demonstrated responsiveness to clinical change correctly in 21 of 25 patients (84%). Construct validity was shown by the ability of the questionnaire to measure the full spectrum of disease; scores ranged from 8 to 99 out of a maximum score of 100. The questionnaire was able to distinguish patients who went on to have surgery (average score, 31) from those who would be treated nonoperatively (average score, 79). The quality of life outcome measure for chronic anterior cruciate ligament deficiency is the first subjective knee scale of its kind to be validated to measure quality of life in patients with chronic anterior cruciate ligament deficiency.