INTRODUCTION: Short-term outcome after hip arthroscopy for femoroacetabular impingement (FAI) has been reported to improve hip function and decrease pain. Only few midterm and long-term studies have been published. The objective of this study was to report midterm results in a consecutive cohort and to study the relation between cartilage lesions and the conversion rate to total hip arthroplasty (THA).

METHODS: Eighty-four FAI patients were followed retrospectively for 6-8 years. The conversion rate to THA, the peri-operative findings and the patient-reported outcome measures were reported.

RESULTS: Fifteen of 84 (18%) patients were converted to THA. The five-year hip survival rate was 83.9% (confidence interval (CI): 75.1-91.5%). The THA group was significantly older, with a mean age of 46.9 years (CI: 42.8-50.8 years) compared with 39.0 years (CI: 36.6-41.6 years) in the non-THA group (p = 0.011). In the THA group, 13 of 15 patients were 40 years or older (p = 0.005). A high-grade acetabular or femoral cartilage lesion was associated with a higher risk of conversion to THA (p = 0.017 and p < 0.0001). Sixty-four of the 69 patients (93%) were willing to repeat their arthroscopy.

CONCLUSIONS: The midterm results for arthroscopic hip-preserving surgery show a high level of patient satisfaction and a good functional outcome. The conversion rate to THA was 18%. High-grade cartilage lesions and age of 40 years and older are risk factors for conversion to THA.

FUNDING: This work was supported by Aleris' Research Foundation, Box 47134, 100 74 Stockholm, Sweden. Registration number: 2014-24.

TRIAL REGISTRATION: not relevant. .