Table 5

Quality assessment of included studies according to the CASP criteria checklist and CASP ratio positive score/negative score

A: Methodological quality
Study type1.
Clear study objective (CS, CC, PC)
2. Population charac­teristics (CS, CC, PC)3.
Cases/
controls same population (CC)
4.
Partici­pation
rate (CS, CC, PC)
5. Partici-
pation rate followup (PC)
6.
Data
presented
properly
(CS, CC, PC)
7.
Instru-
mented
hip
ROM assessment (CS, CC, PC)
8.
Hip
ROM assess-
ment injured/
controls (CC)
9.
Hip
ROM assess-
ment blinded injured/
controls (CS, CC)
10.
Hip
ROM assessed before onset
of groinpain (CC)
11.
Data collection for
≥1 playing season (PC)
12.
Data collection at least every
3
months (PC)
13.
Physical examina-
tion blinded
to
exposure status
(CS, CC, PC)
14.
Prospective
enrolment 
of
subjects
(CC)
15.
Uni- ormulti­variate analysis performed (CS, PC)
16. Logistic regression analysis performed (CC)17.
Relation measures (OR/RR) with 95% CI (CS, CC, PC)
18.
Confounding / effect modification controlled (CS, CC, PC)
19.
N cases
is 
10
times
N independent variables
(at least)(CS,CC,PC)
total%
Arnason et al26PC++NA++++NANANA++NA+NA+++12/1392%
Verrall et al 200730PC++NA++++NANANA++NA+NA+++12/1392%
Enge
bretsen et al19
PC++NA+++NANANA+NA+NA+++10/1377%
Emery et al49PC+NA+++NANANA+NA+NA++NA8/1267%
Ibrahim et al24PC+NA+++NANANA+++NANANA7/1258%
Tyler et al28PC++NA++NANANA++NA+NANA7/1258%
Witv
rouw et al34
PC++NA++NANANA++NA+NANA7/1258%
Nevin et al31CC++++NA+++NANA++NA+NA10/1471%
Verrall
et al 200525
CC+++NA++++NANA+NANA8/1457%
Malliaras et al22CC++NA+++NANA++NA7/1547%
Rambani et al23CC+NA++NANA+NANA4/1429%
B: CASP ratio
Relative CASP quality scorePC7/05/2NA5/24/36/16/1NANANA7/03/43/4NA6/1NA4/34/33/0
CC3/13/12/22/2NA3/14/04/01/30/4NANA3/12/2NA0/40/41/3NA
  • A: Methodological quality scores with the total quality score for all positive validity/precision items and the percentage of the maximum attainable score (%).

  • B: CASP ratio scores <1 (more negative than positive scores per item for all studies) are in bold.

  • CASP, Critical Appraisal Skills Programme; CC, case–control study; CS, cross-sectional study; NA, not applicable item for that study type; PC, prospective cohort study; ROM, range of motion; ‘+’, positive score for item criteria; ‘−‘, negative score for item criteria.