Rate of functional recovery after hip arthroscopy for femoroacetabular impingement syndrome: patient-reported outcomes at three, six, and twelve months.

PURPOSE: To characterise recovery trajectories across nine patient-reported outcomes (PROs) during the first twelve months after hip arthroscopy for femoroacetabular impingement syndrome (FAIS), and to determine whether six-month assessment serves as a representative endpoint.

METHODS

Retrospective analysis of a prospective database (2007-2025). Patients undergoing primary hip arthroscopy for FAIS completed nine PROs pre-operatively and at three, six, and twelve months. Linear mixed-effects models adjusted for age, BMI, sex, morphology, cartilage grade, and labral treatment were the primary analysis; Holm correction controlled the family-wise error rate. MCID and PASS achievement with 95% Wilson CIs were secondary outcomes.

RESULTS

Included were 1,095 hips (44.2% CAM; 52.9% combined; mean age 38.2 ± 12.7 years; 63.3% male). The largest gains occurred at three months (mHHS: Δ + 14.6, 95% CI + 12.8 to + 16.5; iHOT-33: Δ + 20.9, + 18.2 to + 23.5; both p < 0.001). Further improvement occurred through six months. After Holm correction, no instrument showed statistically significant change from six to twelve months (all p-adj > 0.05; effect sizes d = 0.05-0.12). MCID achievement rose from three to six months (mHHS: 57.9% to 69.4%; HOS Sport: 52.9% to 68.2%), with minimal further gain at twelve months.

CONCLUSION

Recovery follows a biphasic pattern: the largest gains occur within three months, with further improvement through six months. After Holm correction, no PRO changed significantly from six to twelve months. Six-month assessment is a pragmatic endpoint for pain, daily-living function, and overall hip scores. HOS Sport and SF-36 PCS warrant twelve-month evaluation in athletes and studies using these as primary endpoints.