Quality assessment of included studies according to the CASP criteria checklist and CASP ratio positive score/negative score
| A: Methodological quality | ||||||||||||||||||||||
| Study type | 1. 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. Participation rate follow up (PC) | 6. Data presented properly (CS, CC, PC) | 7. Instrumented hip ROM assessment (CS, CC, PC) | 8. Hip ROM assessment injured/controls (CC) | 9. Hip ROM assessment blinded injured/ controls (CS, CC) | 10. Hip ROM assessed before onset of groin pain (CC) | 11. Data collection for ≥1 playing season (PC) | 12. Data collection at least every 3 months (PC) | 13. Physical examination blinded to exposure status (CS, CC, PC) | 14. Prospective enrolment of subjects (CC) | 15. Uni- or multivariate 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 al 26 | PC | + | + | NA | + | + | + | + | NA | NA | NA | + | + | − | NA | + | NA | + | + | + | 12/13 | 92% |
| Verrall et al 200730 | PC | + | + | NA | + | + | + | + | NA | NA | NA | + | − | + | NA | + | NA | + | + | + | 12/13 | 92% |
| Enge bretsen et al 19 | PC | + | + | NA | + | + | + | − | NA | NA | NA | + | − | − | NA | + | NA | + | + | + | 10/13 | 77% |
| Emery et al 49 | PC | + | − | NA | + | − | + | + | NA | NA | NA | + | − | − | NA | + | NA | + | + | NA | 8/12 | 67% |
| Ibrahim et al 24 | PC | + | − | NA | + | + | − | + | NA | NA | NA | + | + | + | NA | − | NA | − | − | NA | 7/12 | 58% |
| Tyler et al 28 | PC | + | + | NA | − | − | + | + | NA | NA | NA | + | − | + | NA | + | NA | − | − | NA | 7/12 | 58% |
| Witv rouw et al 34 | PC | + | + | NA | − | − | + | + | NA | NA | NA | + | + | − | NA | + | NA | − | − | NA | 7/12 | 58% |
| Nevin et al 31 | CC | + | + | + | + | NA | + | + | + | − | − | NA | NA | + | + | NA | − | − | + | NA | 10/14 | 71% |
| Verrall et al 200525 | CC | + | − | + | + | NA | + | + | + | + | − | NA | NA | + | − | NA | − | − | − | NA | 8/14 | 57% |
| Malliaras et al 22 | CC | + | + | − | − | NA | + | + | + | − | − | NA | NA | + | − | + | − | − | − | NA | 7/15 | 47% |
| Rambani et al 23 | CC | − | + | − | − | NA | − | + | + | − | − | NA | NA | − | + | NA | − | − | − | NA | 4/14 | 29% |
| B: CASP ratio | ||||||||||||||||||||||
| Relative CASP quality score | PC | 7/0 | 5/2 | NA | 5/2 | 4/3 | 6/1 | 6/1 | NA | NA | NA | 7/0 | 3/4 | 3/4 | NA | 6/1 | NA | 4/3 | 4/3 | 3/0 | ||
| CC | 3/1 | 3/1 | 2/2 | 2/2 | NA | 3/1 | 4/0 | 4/0 | 1/3 | 0/4 | NA | NA | 3/1 | 2/2 | NA | 0/4 | 0/4 | 1/3 | NA | |||
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.