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

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. 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. A total of 546 patients (HA-THA: n&#x2009;=&#x2009;89; THA: n&#x2009;=&#x2009;457) with a mean age of 67.0&#x2009;&#xb1;&#x2009;13.3 years (54% male) and mean follow-up of 52.6&#x2009;&#xb1;&#x2009;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&#x2009;<&#x2009;0.001). Postoperatively, HOOS subscales showed no significant differences between groups except quality of life (HA-THA: 75.7&#x2009;&#xb1;&#x2009;24.0; THA: 82.9&#x2009;&#xb1;&#x2009;18.2; p&#x2009;=&#x2009;0.009). Three patients in HA-THA (3.4%) required a revision surgery. Higher BMI was associated with worse functional outcome in THA group. 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 III retrospective comparative cohort study.