Comparable functional outcomes after total hip arthroplasty in patients with and without prior ipsilateral hip arthroscopy: A comparative cohort study.

PURPOSE: To evaluate whether prior ipsilateral hip arthroscopy (HA) influences the functional outcome of subsequent total hip arthroplasty (THA) in patients with a conversion time of more than 6 months, compared with primary THA. METHODS: In this retrospective cohort study, patients were categorised into two groups, those with prior HA to THA (HA-THA) and those with primary THA (THA). The primary outcome measure was the Hip Disability and Osteoarthritis Outcome Score (HOOS). Secondary outcomes comprised complication rate, revision rates and patient-reported outcome measures (PROMs) including Harris Hip Score (HHS), Oxford Hip Score (OHS) and Visual Analogue Scale. RESULTS: A total of 546 patients (HA-THA: n = 89; THA: n = 457) with a mean age of 67.0 ± 13.3 years (54% male) and mean follow-up of 52.6 ± 28.1 months were included. Both groups demonstrated a significant improvement from pre- to post-operatively in all HOOS subscales with a significantly higher mean improvement in THA (p < 0.001). Postoperatively, HOOS subscales showed no significant differences between groups except quality of life (HA-THA: 75.7 ± 24.0; THA: 82.9 ± 18.2; p = 0.009). Three patients in HA-THA (3.4%) required a revision surgery. Higher BMI was associated with worse functional outcome in THA group. CONCLUSION: Prior ipsilateral HA was not associated with inferior PROMs after THA compared with primary THA. Patients undergoing THA after previous HA can therefore be counselled that a prior HA is unlikely to compromise the functional result of subsequent arthroplasty, but the timing of conversion may be relevant to complication and revision rates. LEVEL OF EVIDENCE: Level III, retrospective comparative cohort study.