Assessing activity participation in the ACL injured population: a systematic review of activity rating scale measurement properties

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Assessing activity participation in the ACL injured
population: a systematic review of activity rating
scale measurement properties
Robert Letchford, Kate Button, Valerie Sparkes & Robert W M van Deursen
To cite this article: Robert Letchford, Kate Button, Valerie Sparkes & Robert W M van Deursen
(2012) Assessing activity participation in the ACL injured population: a systematic review of
activity rating scale measurement properties, Physical Therapy Reviews, 17:2, 99-109, DOI:
10.1179/1743288X11Y.0000000053
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Systematic Review
Assessing activity participation in the ACL
injured population: a systematic review of
activity rating scale measurement properties
Robert Letchford
1,2,3
, Kate Button
1,2,4
, Valerie Sparkes
1,2
, Robert WM van
Deursen
1,2
1
Research Centre for Clinical Kinaesiology, School of Healthcare Studies, Cardiff University, UK,
2
Arthritis
Research UK Biomechanics and Bioengineering Centre, Cardiff University, UK,
3
Aneurin Bevan Health Board,
Royal Gwent Hospital, UK,
4
Cardiff and Vale University Health Board, University Hospital of Wales, UK
Background: Participation is an important factor in assessing both the requirement for and outcome from
anterior cruciate ligament reconstruction. Many patient-reported rating scales exist; however, measure-
ment properties have not been well established.
Objective: To provide a systematic review to identify currently available activity rating scales for anterior
cruciate ligament injured subjects and to evaluate current knowledge of their measurement properties.
Methods: Systematic searches of four databases (Medline, AMED, EMBASE, and CINAHL) without date or
language restriction, using terms structured around the PICOS system were completed on 1st March 2011.
Citation tracking, reference screening and contact with lead authors of key papers completed the search
strategy. Studies using participation rating scales were identified to assess frequency of reporting and
cited validation. Studies assessing one or more psychometric properties of the identified rating scales were
subject to independent data extraction and critical appraisal by two independent authors using published
tools.
Results: Thirty-one rating scales were identified from 241 outcome studies. Most scales were inadequately
developed or validated prior to use. Only three scales (Tegner, CSAS, and Marx) had psychometric
analysis in eight studies of mixed quality. Only the Tegner scale has adequate assessment of reliability,
validity, and responsiveness. The use of type, intensity, and frequency variables in the identified scales is
discussed.
Conclusions: The Tegner scale has been adequately validated; however, other rating scales require further
validation. A comprehensive comparative analysis of clinical applicability and psychometric testing of
existing scales, including clinically useful statistics, is required.
Keywords: Anterior cruciate ligament, Participation, Patient-reported outcome, Systematic review
Introduction
The World Health Organization International Classi-
fication of Functioning, Disability and Health (WHO
ICF) describes four core measures of health: structure,
function, activity, and participation.
1
The outcome of
anterior cruciate ligament (ACL) reconstruction is
reported with robustly validated measurement tools for
structure (e.g. magnetic resonance imaging),
2
function
(e.g. International Knee Documentation Committee
subjective knee form),
3
and activity (e.g. functional hop
tests).
4
However, participation is more complex to
measure, and tools are less clearly validated.
Outcomes in the participation domain assess
‘involvement in life situations’
1
a measure of what a
person is doing. This is important in ACL injury since
both clinicians
5
and patients
6
consider participation
restrictions an important factor when deciding on
management and resolution of these restrictions is an
expected outcome of surgical reconstruction
7,8
that is
related to patient satisfaction.
9
For researchers
participation is important since it may influence the
significance of outcomes from other domains of the
ICF.
7
For instance, outcomes from the function
domain are frequently based on symptoms which can
be dependent on the type and intensity of activities in
which a person participates. Similarly, activity based
measures are only significant if the ability to execute a
task also translates into the ability to participate in
Correspondence to: Robert Letchford, School of Healthcare Studies, Ty
Dewi Sant, Heath Park Campus, Cardiff University, Cardiff, Wales CF14
4XN, UK. Email: letchfordrh@cf.ac.uk
ßW. S. Maney & Son Ltd 2012
DOI 10.1179/1743288X11Y.0000000053 Physical Therapy Reviews 2012 VOL.17 NO.2 99

that task. Accurate assessment and reporting of
participation is therefore required for clinical decision
making and appropriate interpretation of clinical and
research outcomes.
10–12
Whilst many methods for assessing participation
have been suggested, patient-reported outcomes have
gained acceptance in the ACL literature and clinic.
These tools are commonly referred to as activity
rating scales, a name that was established prior to the
current ICF classification that can lead to confusion
over which ICF domain is being assessed. Despite
their name, activity rating scales provide a quantifi-
cation of what a person is doing and therefore fulfil
the participation domain of the ICF. The commonly
stated aim of anterior cruciate ligament reconstruc-
tion, to restore participation at pre-injury levels,
13
can be assessed adequately with a yes or no grading
to define success for that individual. However, given
that many patients may not share this aim,
14
or will
never achieve it
15,16
a more sophisticated tool is often
required. Similarly, when considering the impact
which activity participation may have on the outcome
of an intervention the tool must be capable of both
quantifying an individual’s level of participation and
defining groups for comparative analysis.
17
Authors of the first rating scales
10,11,18–20
should be
commended for identifying the importance of asses-
sing participation in the ACL injured population and
for developing rating scales. However, by current
standards, many were poorly developed and insuffi-
ciently investigated before being introduced. There
are fears that inadequately validated patient-report-
ed outcomes may in part be responsible for the
large variations seen in published outcomes.
21
Psychometric testing has been applied to a range of
outcome instruments and now forms the standard by
which such tools are assessed.
22,23
This assessment
should include clinical practicality and applicabi-
lity, reliability, validity and responsiveness as mini-
mum requirements.
22,23
Many reviews of pa-
tient-reported knee rating instruments have been
conducted,
24–30
few have addressed participation
rating
31
and none have focused on measurement
properties of activity rating scales.
A well validated measurement tool must also be
useful in the clinical setting and capable of influencing
intervention decisions. For this the tool must measure
those aspects of participation that are of most concern
to patient and clinician. The components of participa-
tion assessed by each tool need to be understood in the
context of how each may influence the outcome, and
therefore how they can be appropriately applied in the
clinical environment.
This systematic review will identify activity rating
scales used in the ACL injured population, examine
the available evidence for psychometric properties,
and discuss the clinical implications of tools based
around different components of participation.
Study Aims
1. Systematically identify all currently available activ-
ity rating scales for assessment of participation in
ACL injured subjects.
2. Where evidence exists, provide a systematic critical
appraisal of each scale which will include an
evaluation of design, psychometric properties, and
clinical implications of the components assessed.
Methods
A two stage systematic search was conducted with no
date or language restriction in four medical databases
(Medline, AMED, EMBASE, and Cinahl) up to the 1st
March 2011. Keywords were developed using the
PICOS (participants, interventions, comparators, out-
comes, and study design) system and adapted for each
database to account for differences in index terms. The
full search strategy for Medline is detailed in Table 1.
Keywords included; participants: Anterior Cruciate
Ligament, ACL, Anterior Cruciate Ligament recon-
struction, Anterior Cruciate Ligament rupture;
interventions: outcome assessment, questionnaire, mea-
surement, treatment outcome; comparators: none were
specified; outcomes: sport, participation, exercise, phy-
sical activity, return to sports; study design: reliability,
validity, responsiveness and psychometrics.
The first search combined participant, intervention
and outcome keywords to identify all studies report-
ing activity participation as an outcome of interven-
tions for ACL injury. Studies were abstract filtered
for appropriateness on the following criteria; a study
that includes a patient-reported tool or questionnaire,
measuring physical activity participation in adult
Table 1 Full search strategy used in Medline
1 Exp*Anterior cruciate ligament 7652
2 ACL.mp{6456
3 1 OR 2 10 289
4 Exp ‘reproducibility of results’ 207 148
5 Reliability.mp 71 199
6 Validity.mp 76 552
7 Responsiveness.mp 67 759
8 EXP Psychometrics 43 078
9 4 OR 5 OR 6 OR 7 OR 8 348 327
10 EXP Outcomes assessment (healthcare) 505 855
11 EXP Questionnaires 227 746
12 Rating scales.mp 50 927
13 Measurement.mp 330 919
14 EXP treatment outcome 471 671
15 10 OR 11 OR 12 OR 13 OR 14 1 056 053
16 EXP Sports 88 865
17 Return to sport.mp 208
18 EXP recovery of function 19 977
19 Participation.mp 92 438
20 Physical activity.mp 34 869
21 EXP exercise 53 931
22 16 OR 17 OR 18 OR 19 OR 20 OR 21 259 219
23 3 AND 15 AND 22 362
24 3 AND 9 AND 15 AND 22 22
Note:*EXP5explode search term; {mp5keyword search.
Letchford et al. Assessing activity participationintheACLinjuredpopulation
100 Physical Therapy Reviews 2012 VOL.17 NO.2

ACL injured or reconstructed subjects. Full text
articles were collected only for those studies where
the rating scale was not identifiable from the abstract.
Rating scales were extracted and registered in an
electronic database. Reference screening for addi-
tional outcome studies and papers of psychometric
testing was completed.
The second search strategy was to identify studies
reporting psychometric properties of the identified
rating scales. Scales were accepted on the basis of
frequent use or the presence of reference to psycho-
metric analysis. The initial search was combined with
the study design keywords, and reference screening;
additional searches using keyword, title and author
were completed for each of the accepted scales. Papers
were reference screened and the initial publication of
each tool was citation tracked. Authors of accepted
scales were contacted by e-mail with the search results
and a request for information of any further published
or unpublished material. Each psychometric study was
abstract screened for appropriateness for one or more
of the following criteria; describing tool development;
detailing instructions for use of the tool; or reporting
at least one psychometric property. Full text articles
were obtained for all psychometric studies.
Critical appraisal and data extraction were com-
pleted using published tools designed specifically for
psychometric studies; a detailed description of their use
has been previously described.
23
Both tools have been
used in recent reviews of patient-reported outcome
instruments; for neck pain,
23
shoulder function,
32
and
obesity management.
33
They have been investigated
for inter-rater agreement (k50.43 to 0.92) and in-
ter-rater reliability (ICC50.91: 95%CI50.86–0.94).
23
Appraisal and extraction processes were completed
separately, by two independent reviewers (RL and
KB). If disagreement was irresolvable by a consensus
on a second review of the manuscripts, plans were
made for a third reviewer to be consulted and con-
sensus agreed.
The critical appraisal tool assesses the quality of
reporting for 12 criteria spread across five categories:
study question; study design; measurement; analysis;
and recommendation (see Table 2). Each criterion is
scored 0, 1 or 2 points with a high score indicating
high quality of reporting. The scores can be summed
and expressed on a scale from excellent to poor,
although analysis of each individual criterion is
encouraged.
23
The following data were extracted from each study
following the published guidance;
23
population, inter-
vention, clinical usefulness/practicality (readability,
interpretability, time to administer, administration
burden, and cultural applicability), reliability [relative
reliability reported with intraclass correlation coeffi-
cient (ICC), absolute reliability reported with standard
error of the mean (SEM) and minimal detectable
change (MDC)], content/structural validity (internal
consistency, content validity, floor and ceiling effects,
factorial validity, item response, and Rasch analysis),
construct/criterion validity (known groups, conver-
gent, divergent, longitudinal, concurrent criterion,
Table 2 Evaluation criteria from the critical appraisal tool. Reproduced with permission from MacDermid et al.
23
Evaluation criteria Score
Study question 210
1. Was the relevant background work cited to define what is currently known about the
psychometric properties of measures under study, and the potential contributions of the
current research question?
Study design
2. Were appropriate inclusion/exclusion criteria defined?
3. Were specific psychometric hypothesis identified?
4. Was an appropriate scope of psychometric properties considered?
5. Was an appropriate sample size calculated?
6. Was an appropriate retention/follow up obtained?
Measurements
7. Were specific descriptions provided of the techniques used to collect the
measurements reported?
8. Did measurement procedures use standardized techniques (and other
methods required) to minimize potential sources of error/misinterpretation in
the individual measures taken from the study?
Analysis
9. Were analyses conducted for each specific hypothesis or purpose?
10. Were appropriate statistical tests conducted to obtain point estimates of
the psychometric property?
11. Were appropriate ancillary analysis done to describe properties beyond
the point estimates (CI, benchmark comparisons, SEM/MID)
Recommendations
12. Were the conclusions/clinical recommendations supported by the study
objectives, analysis and results?
Subtotals (of columns 1 and 2)
Total score (sum of subtotals/246100)
If an item is deemed appropriate then you can sum the score of items/26number of items 6100.
Letchford et al. Assessing activity participationintheACLinjuredpopulation
Physical Therapy Reviews 2012 VOL.17 NO.2 101

and predictive criterion) and responsiveness/clinical
change [responsiveness reported with effect size (ES),
standard response mean (SRM) and minimal clinically
important difference (MCID)].
Previous appraisal of activity rating scales has
provided well reasoned and valid criticism.
31
Two of
these criticisms are of particular importance, are
unrelated to psychometrics, and would not be captured
by the data extraction tool. These are the ability to
detect the knee abuser (a person who participates in a
high level of activity despite significant knee symp-
toms) and the ability to detect alterations in activity
unrelated to the knee. These two criteria were assessed
during data extraction on a simple yes/no scale.
Results
Results of the search strategy are presented in Fig. 1.
After initial title and abstract screening 325 outcome
studies were reviewed, nine were excluded (five review
papers, one discussion paper, one retracted by pub-
lisher, one not available in British library, and one
French language paper), leaving 316. Of these 75
(24%) did not report activity participation, leaving 241
studies using 37 different rating scales. Six scales did
not meet inclusion criteria and were excluded; four
rated symptoms with activity (Knee Outcome Survey
Sports Activity Scale, Knee Osteoarthritis Outcome
Scale, Orthopadischen Arbeitsgruppe Knie, ACL
Return to Sport Index); the activity participation
Figure 1 Flowchart showing systematic search process
Letchford et al. Assessing activity participationintheACLinjuredpopulation
102 Physical Therapy Reviews 2012 VOL.17 NO.2

rating was not reportable as a separate subscale in one
(ACL Quality of Life); and one was not published in
English (Innsbruck).
A total of 31 rating scales were identified. They can
be grouped into three themes; scales that assess
return to sport based on either pre-injury compar-
isons or time,
9,10,34–50
scales which rank sports or
activities
7,18,19,51,52
and those which rank knee
motions and forces.
10,17,20,53,54
Only five scales take
account of frequency of participation,
10,17,42,47,52
and
only three the intensity.
7,18,19
The most frequently used scale is the Tegner
activity rating scale (n5121), followed by IKDC
activity rating (n538), Marx activity rating scale
(n57) and Cincinnati sports activity scale (n55).
Twenty-five authors used their own scales with no
reference to validation of psychometric properties.
The Marshall score was used in three studies
34,55,56
and the University of California activity scale in
one
57
with no cited validation.
Studies of psychometric properties (n58) were
identified for just three of the scales; Tegner activity
rating scale (n55),
11,12,58–60
Cincinnati sports activity
rating scale (n52),
10,61
and Marx activity rating scale
(n51).
17
The authors of each of these scales were
contacted by e-mail for missing publications or
unpublished data, all replied but no new material
was identified. Due to the high reporting rate of the
IKDC activity scale and the international standing of
the authors, this scale was included in the second
search strategy and an IKDC team member was
contacted (Dr JJ Irrgang), but no study specifically
assessing the activity rating scale was identified.
During critical appraisal there was agreement
between the two reviewers on 70 of the 84 questions
(83%); where there was disagreement it was by a
maximum of one point and all were fully resolved by
consensus. The quality of the studies was variable (see
Table 3), with none scoring greater than 90% which is
the criteria to be classified as excellent. Three were
ranked as very good (71–90%);
58–60
two as good (51–
70%);
12,61
one as fair (31–50%);
17
and two poor
((30%).
10,11
There were no disagreements between the reviewers
in the data extraction. The results are presented in
Table 4 and data for the two additional criteria in
Table 5. The results will be described in detail for
each of the tools below.
International Knee Documentation Committee
(IKDC) Activity Rating Scale
The IKDC activity rating scale did not meet the
primary inclusion criteria for the review since there
were no psychometric studies available. However, as
the second most reported tool, used in 15.8% (n538)
of the identified outcome studies, it was entered into
search two to assess its validation status. The IKDC
was formed in 1987 by a group of leading knee
surgeons with the goal of determining a common
terminology for the evaluation of knee ligament
injuries. Activity participation was included on the
resulting knee evaluation form
54
and the subse-
quently developed subjective knee form.
3
The scale
uses a four point scale (Level 1 jumping, pivoting,
hard cutting, football, soccer; Level 2 heavy manual
work, skiing, tennis; Level 3 light manual work,
jogging, running; level 4 sedentary work and activities
of daily living) to describe activity participation pre-
injury, pre-treatment and present, with a yes/no
statement to establish whether changes are knee
related. Whilst both the evaluation form and
subjective knee form has received appropriate valida-
tion, no papers assessing psychometric properties of
the activity rating section as an independent measure
were identified. The scale will detect knee abusers
when used in conjunction with the subjective knee
form and will identify non-knee related changes.
Tegner Activity Rating Scale
The Tegner activity rating scale was introduced in
1985 as a measure of handicap as described by the
World Health Organization international classi-
fication of impairment, disability and handicap.
7
Designed to complement the Lysholm knee scale
11
it
was intended to assess changes in activity participation
for a single subject over time rather than differences
between subjects.
7,62
The authors should be praised as
Table 3 Results of the systematic critical appraisal of each psychometric paper
Study Scale
Item evaluation criteria
Total %12345 6 789101112
Barber-Westin et al. (1999)
61
CSAS 2 1 1 1 1 2 1 0 0 1 1 2 54
Briggs et al. (2006)
58
Tegner 1 1 2 2 1 2 1 1 2 2 2 2 79
Briggs et al. (2009)
59
Tegner 2 1 2 1 1 2 2 1 2 2 2 2 83
Briggs et al. (2009)
60
Tegner 2 2 0 1 1 NA 2 2 2 2 1 2 77
Noyes (1989)
10
CSAS 1 0 0 0 0 0 2 0 1 0 0 0 17
Marx et al. (2001)
17
Marx 1 1 1 1 0 1 1 0 1 1 0 1 38
Paxton et al. (2003)
12
Tegner 1 2 1 1 0 1 1 1 2 2 0 2 58
Tegner and Lysholm (1985)
11
Tegner 0 1 0 0 0 0 0 0 1 1 0 1 16
Note: Each of the 12 questions scored from a maximum 2 and minimum 0.
Letchford et al. Assessing activity participationintheACLinjuredpopulation
Physical Therapy Reviews 2012 VOL.17 NO.2 103

Table 4 Psychometric data extracted from each of the included studies
Study
Tegner and
Lysholm
(1985)
11
Paxton et al.
(2003)
12
Briggs et al.
(2006)
58
Briggs et al.
(2009)
59
Briggs et al.
(2009)
60
Noyes
(1989)
10
Barber-Westin
et al. (1999)
61
Marx et al.
(2001)
17
Population ACL
deficient
(n573)
Acute (n5110)
and
recurrent
(n543)
patellofemoral
dislocation
Meniscal
injury
ACL
reconstruction
(n5505)
Healthy
(n5500)
Chronic
knee
injured
(n559)
Knee
injured
(n550)
Knee injured
(n550)
255 M;
245 F
55 M; 21 F Isolated or
combined
(n5122)
Age 37 years
(18–77 years)
Age 41
years
(18–85 years)
28 M; 22 F 27 M; 23 F
77 M; 45 F Age 36 years
(13–65 years)
Age 32.8 years
(12–57 years)
item
generation/
reduction only
Age 48 years
(14–76 years)
Healthy
(n550)
Healthy (n540)
22 M; 28 F 27 M; 13 F
Age 34 years
(20–59 years)
Age 33.7 years
(18–50 years)
Reliability N576 N5119 N5122 N550 – – N5100 N540
Retest Retest 21
days
(13–42)
Retest
,4 weeks
Retest
,4 weeks
Retest
4–13 days
Retest 1 week
ICC5
0.90–0.97
ICC50.92 ICC50.817
(95%CI5
0.75–0.87)
ICC50.82
(95%CI5
0.66–0.89)
ICC50.98 ICC50.97
SEM50.4 SEM50.64
MDC51 MDC51
Content
validity
–N5153 N580 N5687 – – – Excellent item
generation and
reduction process
Floor50% Floor52.5–5.5% Floor58%
Ceiling50% Ceiling50–2% Ceiling53%
Known
groups
validity
–– N580 N5687 – – –
All 8 hypothesis
significant
at P,0.05
All 6 hypothesis
significant
at P,0.05
Convergent
validity
– – – – Lysholm
stairs
(p50.20;
P50.01)
and squat
(p50.14;
P50.001)
–– AllatP,0.05
Tegner r50.66
Daniel r50.52
CSAS r50.67
Divergent
validity
– Knee rating
scales
r50.20–0.54
– – Inverse
correlation
with age
P520.44
P50.01
– – Age r520.42;
P50.02
Differed by
gender
P50.001
Criterion
validity
–– N580 N5170 – – – –
SF-12
physical
score
SF-12
physical
score
r50.46;
P,0.05
p50.2;
P,0.05
IKDC p50.22;
P,0.001
Responsiveness – – N580 N5505 – – – –
Isolated
ES50.61
ES51.0–1.1
SRM 0.6 SRM50.84–1.2
Combined
ES50.83
SRM 0.704
Note:N5number of subjects; M5male; F5female; ICC5intraclass correlation coefficient; SEM5standard error of measurement;
MDC5minimal detectable change; ES5effect size; SRM5standard response mean; IKDC5international knee documentation committee.
Blank sections indicate that no data were presented.
Letchford et al. Assessing activity participationintheACLinjuredpopulation
104 Physical Therapy Reviews 2012 VOL.17 NO.2

being the first to develop such a tool, which has now
become the most frequently used participation rating
scale for various knee disorders.
58
The original manuscript
11
contains a briefly
explained rationale. The development process is
inadequately described with no literature review
presented. Whilst patients were used in the item
generation there is minimal description of item
reduction. The text states the use of a troublesome
rating which is not clearly defined. The scale is scored
out of 10 points using the Gutman method. This
method is applied to ranked scales, the score is given
to the highest selected level, and it is inferred that
lower ranked levels are also included. Brief descrip-
tors of competitive and/or recreational sports, occu-
pations and activities of daily living are provided to
describe each level. Participation in national and
international soccer defines the top score of 10 and
currently on sick leave due to knee injury a low score
of 0. It is suggested that results should be presented as
a retrospectively reported pre-injury and prospec-
tively reported post-injury and post-intervention
score.
7
Rodkey et al.
62
have proposed a method to
enable changes in the results to be normalized across
diverse populations, which they term a Tegner
index.
62
The index is calculated from pre-injury,
preoperative and postoperative scores and indicates
the percentage of lost activity level that is regained
following an intervention.
Five studies reporting psychometric properties of the
Tegner scale were identified, of which three were
assessed as very good;
58–60
one good;
12
and one poor.
11
Study samples included healthy individuals,
60
and
patient groups with ACL injury and reconstruction,
59
meniscal injury
58
and patellofemoral dislocation.
12
There is no evidence for clinical usefulness/practicality
of the tool. Whilst it has been suggested that the
European bias of the listed sports and activities may
hinder understanding particularly in the USA,
no evidence for administration burden, readability
or interpretation is presented. There is evidence
of excellent test–retest reliability from four
studies,
11,12,58,59
with reported ICCs ranging from 0.82
to 0.97, SEM from 0.4 to 0.64 and MDC of 1. There is
good evidence for validity of the scale with reports of
acceptable (,30%) floor and ceiling effects in three
studies,
12,58,59
known groups validity in two studies,
58,59
convergent validity (Lysholm stairs and squat sub-
scales) in one study,
59
divergent validity (knee rating
scales, age, and gender) in two studies
12,59
and criterion
validity (SF-12 physical and IKDC) in two studies.
58,59
There is evidence for acceptable responsiveness with
moderate to large effect sizes and SRMs reported in two
studies.
58,59
Usefulness and practicality are inade-
quately investigated and reports of responsiveness lack
the clinically useful statistic of minimal clinically
important difference. The scales developer was involved
in two of the studies whilst three were performed by
independent groups.
The scale has been criticized for: ill defined use
of arbitrary descriptors such as competitive and
recreational;
31
the ill defined method in which sports
are ranked;
31
simultaneous assessment of occupa-
tional and sporting activity;
31
occupational activities
that are not comparable to sporting activity at the
same level;
31
a dominance of European sports leading
to a lack of cross cultural application,
58
all of which
remain valid. The scale is capable of detecting knee
abusers when used in conjunction with the Lysholm
scale, but does not allow for detection of non-knee
related changes in activity.
Cincinnati Sports Activity Scale (CSAS)
First published in 1989 as one of 13 subscales that
form the Cincinnati Knee Rating System, the CSAS
is based around two criteria, frequency of par-
ticipation and specific knee functions. The original
manuscript
10
offers a very well reasoned and evi-
denced basis for development of the tool, but lacks
evidence of item generation and reduction techniques
or psychometric testing.
The resulting tool is a 12-point scale scored out of a
possible 100 points using a Gutman method. The
dominant criterion, frequency, is assessed through
four levels: level one 4–7 days/week, level two 1–
3 days/week, level three 1–3 times/month and level
four no sports. Each frequency level is divided by
specific knee functions; category one activities are
jumping, pivot cutting; category two are running,
twisting and turning; category three are none of
these. Points are allocated to each group in descend-
ing order of frequency and knee function, a
maximum 100 for level one pivoting sports and zero
for severe problems with level 4 activities.
Two studies reporting psychometric properties of
the CSAS were identified, of which one was assessed
as good
61
and one poor.
10
There is little evidence for
clinical usefulness and practicality. It is suggested
that data can be presented in five different ways:
10
as
a percentage of the population at each level to
describe groups; an individual’s level; change in level;
agreement with patient’s goals; or level deemed
acceptable to the clinician, which makes it confusing
Table 5 Capability of rating scale to detect the knee abuser
and non-knee related changes in activity participation
Scale Detect knee abuser
Detect non-knee
related change
IKDC Yes Yes
Tegner Yes No
CSAS Yes Yes
Marx Yes No
Letchford et al. Assessing activity participationintheACLinjuredpopulation
Physical Therapy Reviews 2012 VOL.17 NO.2 105

for clinicians when reporting and interpreting results.
There is no evidence for readability or interpretability
and there are concerns that terms such as pivoting
and cutting require more explanation than is given.
There is evidence of excellent test–retest reliability
(ICC50.98) in one study;
61
however, no other
psychometric data are available for the CSAS despite
a comprehensive analysis of validity and responsive-
ness for the other subscales of the Cincinnati Knee
Rating System.
61
It should also be noted that the
reliability data are from two sample subsets consist-
ing of 50 healthy and 50 chronic knee injured sub-
jects, not from the larger ACL reconstructed group
used for validity testing of the other subscales. There
is no evidence for validity or responsiveness. Both
studies were conducted within the research team of
the tool developer.
When used with the appropriate counterparts of
the Cincinnati Knee Rating System, the CSAS will
detect knee abusers and non-knee related changes in
activity. The CSAS scale is highly dependent on
frequency of participation at the expense of both
intensity and type of task.
Marx Activity Rating Scale
First published by Marx et al. this tool was developed
to enable the comparison of activity participation
between study groups and aid generalizability of
research findings, although it has subsequently been
recommended
30
and used
63
as a longitudinal outcome
score. The original manuscript
17
provides an appro-
priately reasoned and defined development process,
there is adequate review of the literature, and appro-
priate item generation (consultation with specialists
and 20 knee injured patients) and reduction (50 knee
injured patients ranking for importance and severity).
The scale is based upon the criterion of specific
knee functions and frequency of participation. Each
of four knee functions (running, cutting, decelerating,
and pivoting) are rated on a five point scale of
frequency (,1 time in a month, 1 time per month,
one time in a week, 2 or 3 times in a week or 4 or
more times a week) and scored between zero and four
points. The scale is scored by adding the scores to
give a total out of a possible 16 points, with a higher
score indicating more frequent participation.
One study reporting psychometric properties of the
Marx activity rating scale was identified, which was
appraised as fair.
17
This study establishes usefulness
and practicality in a knee injured patient group.
There is evidence for excellent test-retest reliability
(ICC50.97), correlation with three other activity
rating scales (Tegner, Daniel,
20
and CSAS) demon-
strates evidence for convergent validity and an
inverse correlation with age demonstrates evidence
for divergent validity. All psychometric analyses were
conducted in a small healthy sample (n540).
Reliability data are limited as SEM, MDC and
confidence intervals (CI) are not reported, and there
are no responsiveness data, which can be explained
by the initial intention not to use the tool for
longitudinal follow up. The study was conducted by
the tool developer.
The scale is very specific to those activities which
challenge the ACL injured athlete and is very
frequency dependent. Descriptions are usefully
worded, to eliminate ambiguity and facilitate com-
prehension. There is a concern that the scale will not
adequately differentiate those people who remain
active in non-knee aggravating activities from those
that give up sports entirely, creating a possible floor
effect that requires investigation. The IKDC sub-
jective knee form is recommended as an adjunct
scale
17
which would allow detection of the knee
abuser, but there is no way of detecting non-knee
related changes.
Discussion
The systematic search strategy was comprehensive
and compares well to recently reported searches for
the Tegner activity scale,
59,63
providing reassurance
that results were not affected by missing studies.
There were fewer than the 208 papers reported by
Lysholm and Tegner
29
and 200 reported by Briggs
et al.;
59
however, this would be expected since both
these searches included all knee conditions, whilst the
current review was restricted to ACL injured subjects.
A horizon analysis could be used to estimate missed
articles, but was not performed in this study. It is
possible that selective reporting bias limits the
presentation of negative results in published studies.
There was evidence of missing data for some
hypotheses in one of the included studies.
61
It is
possible that the review was affected by publication
bias; however, contact with authors in the field
indicated that they were not aware of any unpub-
lished data relating to their scales.
Language restrictions were not applied to the
searches, and of the 30 foreign language papers
identified in the first search only one was excluded
due to lack of an English abstract. Two Dutch
language psychometric papers identified in the refer-
ence screening of one paper
64
were not included. Both
these papers reported on the CSAS, with the Neeb
et al.
64
report presenting reliability data (r50.64–
0.84)
65
and correlation of the Tegner and CSAS with
the Lysholm score (Kendall Tau b of 0.29 and 0.47
respectively).
66
This reliability data are slightly lower
than that reported by Barber-Westin et al,
61
but does
not substantially influence the results of this review.
Translation of these articles was not attempted, which
is a potential weakness in the study design.
Letchford et al. Assessing activity participationintheACLinjuredpopulation
106 Physical Therapy Reviews 2012 VOL.17 NO.2

None of the studies scored excellent on the critical
appraisal. The three highest scoring studies (very good)
were also the most recent and conducted by the same
research team.
58,59,60
The introductory texts to all three
scales scored badly with two in the poor
10,11
and one in
the fair
17
category. These early studies were completed
before psychometrics had gained recognition in the
development of patient-reported outcomes in ortho-
paedics, which may explain why earlier studies per-
formed poorly and that quality has improved with time.
Analysis of the appraisal data shows particular
deficiencies in three criteria. Sample size was poorly
justified in all studies with none including an appro-
priately described power analysis. Standardizing of
measurement procedures was often not clearly
described, leaving doubt over how data were collected
and handled. Finally, there was inadequate use of
appropriate ancillary analysis to describe properties
beyond the point analysis. Test–retest reliability is
frequently reported; however, data are often restricted
to the intraclass correlation coefficient and there is
inadequate reporting of confidence intervals and the
clinically useful standard error of measurement and
minimum detectable change. Various measures of
validity are reported but none of the scales have been
comprehensively assessed with all the recommended
methods. Responsiveness is inadequately reported and
when data are available it is limited to effect sizes and
standard response means; only two studies
58,59
made
reasonable attempts to do this, but neither presented
the clinically useful statistic of minimal clinically
important differences. All four scales are capable of
detecting knee abusers when combined with the
recommended partner knee rating scales, only the
CSAS and IKDC are capable of detecting non-knee
related changes.
Of the 31 scales identified only the Tegner activity
rating scale has received adequate investigation of
psychometric properties. The results should be
interpreted with the benefit of its associated knee
rating scale, the Lysholm scale, and investigators
should be mindful of the impact of non-knee related
causes of score changes. Despite rigorous develop-
ment processes there is currently insufficient psycho-
metric evidence for the CSAS or Marx scales. Whilst
all scales appear to fulfil the clinical usefulness and
practicality requirements for administration burden,
this is not reported in the studies. There are concerns
over the readability and interpretability of technical
terms in the CSAS and cultural applicability of some
specified sports in the Tegner.
Each of the identified tools measures one or more
components of participation from three primary
themes, type of activity, frequency, and intensity.
Each will be described and the clinical implications
discussed.
Type of Activity
The description of activity type falls in one of three
categories, return to sports, ranked sports or knee
stress. Return to sports is assessed in one of two
distinct ways. First, a retrospective comparison with
pre-injury levels, using either subjective descriptors
ranked on three or four point scales,
9,34–37,39,40,50
a
VAS scale
49,50
or a simple yes/no answer
38,40,46
which
is highly dependent on the ability to accurately recall
previous activity. Second, the time taken to return
to sport or activity,
41,43–45,48
which is reliant upon
accurately defining what constitutes a ‘returned’
state, something which is not easily standardized,
particularly amongst recreational athletes.
Activities and sports have been listed either with
a pre-determined rank
7,18,53
or for the subject to
provide a numerical quantification of participation
frequency or symptom provocation.
19,51
The primary
concern with this type of scale is the criteria selected
to perform the ranking of activities, where agreement
is often lacking.
31
The importance of condition
specificity should also be considered in the ranking
since there are sports where demands on the knee are
extremely high, but ACL injury may have a small
effect (e.g. road cycling). Another concern is how a
subject responds when their sport is not listed,
31
since
there is no guidance on how the ranks are assigned.
Knee stress is often used as an alternative to
ranking of named sports
10,17,18,20,52,54
on the basis
that it represents the required level of dynamic knee
stability and risk of injury. This eliminates the need to
list sports as individuals can assess the motions they
undergo in any activity and rank them.
17
Activities
involving pivoting, cutting, and rapid deceleration
are considered to be ranked above those which do
not. It is important to consider the manner in which
this is communicated to subjects as technical descrip-
tors such as cutting and pivoting are potentially not
familiar terminology to most subjects and may
require explanation.
30
When condition specific scales
use these motions in isolation, a floor effect is likely,
since all activities that do not include these will be
ranked at the bottom of the scale.
Intensity
Intensity has been measured in three distinct ways.
Firstly through competitive level
18,49,52
with the
assumption that competitive sports are more intense
than those played recreationally, although the inter-
pretation of ‘competitive’ is likely to be ambiguous.
Secondly by using a subjective descriptor such as
strenuous, stressful, moderate or light.
53,54
Thirdly, a
reflection on pre-injury level,
49
which has a much
stronger reference point and will serve well to define
return to sport for an individual, but will not allow
for comparison between individuals.
Letchford et al. Assessing activity participationintheACLinjuredpopulation
Physical Therapy Reviews 2012 VOL.17 NO.2 107

Frequency
Frequency is most often measured in units of times
perweekormonth,
10,17,52
only one scale measures
hours per week.
42
Whilst frequency is undoubtedly
an important factor in determining participation,
there are limitations in its application. Scales
highly dependent on frequency may assess someone
who participates in low risk activity on a frequent
basis at the same level or above someone who
participates in high risk activity infrequently. In
the case of ACL deficiency a successful adaptor
could be ranked at a higher activity level than their
pre-injury status despite significant reduction in
participation.
Whilst type, frequency, and intensity are undoubt-
edly important components of participation assess-
ment, it is not yet clear which combination or
method of assessment provides the analysis with
most significance to clinical decisions or functional
outcomes. The identified scales measure each com-
ponent with different emphasis; the IKDC is heavily
based on activity type, the Tegner combines type
and intensity and both the Marx and CSAS are
dependent on frequency. Further investigation to
determine which of these components most signifi-
cantly impacts on patient satisfaction and functional
outcomes would enable tools to be selected on the
basis of clinical utility as well as measurement
properties.
Conclusion
Activity participation is important for selecting inter-
ventions for ACL injured subjects and establishing
outcome for ACL reconstruction, and therefore
requires appropriately validated measurement tools.
This systematic review identified many rating scales
which have three common measurement components
(type, intensity, and frequency) and considerable
variation in the methods for describing them. The
choice of components and methods will have implica-
tions for the outcome, and clinical application.
Currently there is no method which is clearly superior
for application in the clinical setting. Unfortunately,
only the Tegner activity rating scale has received
appropriate investigation of the recommended psy-
chometric properties. There is a need for further
psychometric investigation of the Marx, IKDC, and
CSAS scales, which should include a comprehensive
analysis of clinical usefulness, reliability, validity, and
responsiveness. Future studies should include calcula-
tions of MCID and MDC to be useful to clinicians and
patients. A comparative analysis of measurement
properties of these four scales, and the relationship
of each to patient satisfaction and functional outcome
is required if recommendations for a single standard of
reporting is to be achieved.
Acknowledgements
The authors are grateful to Dr J MacDermid for
permission to use the critical appraisal system;
Professor Y Tegner, Dr J J Irrgang, Dr R Marx
and Dr S Barber-Westin for responses to informa-
tion requests; Cardiff University Systematic Review
Network (SYSNET) for assistance with registra-
tion and protocol development; Research Capacity
Building Collaboration Wales for Scholarship fund-
ing to complete this project
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