Hip muscle strength in male and female patients with femoroacetabular impingement syndrome: Comparison to healthy controls and athletes.

OBJECTIVES

To examine hip muscle strength deficits in patients with femoroacetabular impingent syndrome (FAIS), with special emphasis on potential sex- and comparison-related (between-subject vs within-subject) differences.

DESIGN

Cross-sectional comparative study.

PARTICIPANTS

Forty FAIS patients (20 women), 40 healthy controls (20 women) and 40 athletes (20 women).

MAIN OUTCOME MEASURES

Hip abduction, adduction and flexion isometric strength was tested using a commercially-available dynamometer. Two between-subject comparisons (FAIS patients vs controls and FAIS patients vs athletes) and one within-subject comparison (inter-limb asymmetry) of strength deficits were conducted, based on the calculation of respective percent differences.

RESULTS

For all hip muscle groups, women were 14-18% weaker than men (p < 0.001), but no sex-related interactions were observed. For all hip muscle groups, FAIS patients were 16-19% weaker than controls (p = 0.001) and 24-30% weaker than athletes (p < 0.001). For FAIS patients, the involved hip abductors were 8.5% weaker than the uninvolved ones (p = 0.015), while no inter-limb asymmetry was observed for the other hip muscles.

CONCLUSION

Sex had no influence on hip muscle strength deficits in FAIS patients while a major impact of comparison method/group was observed. Hip abductors showed consistent deficits for all comparison methods, suggestive of a possible greater impairment compared to hip flexors and adductors.