Spencer-Gardner, Luke

Abstract Introduction Understanding factors that impact outcomes of total hip arthroplasty (THA) can aid clinical decision-making and patient counselling. The purpose of this study was to investigate functional outcomes, complications, and reoperation rates among patients undergoing primary THA after hip arthroscopy (HA-THA) compared to a matched cohort of primary THA patients without prior arthroscopy (THA-only). Methods A retrospective review was performed to identify all patients who underwent primary THA after prior hip arthroscopy from 2009-2022 at a single institution. Patients with a history of revision arthroscopy were excluded. Cases were propensity-matched with primary THA controls in a 1:4 ratio by age at time of THA, sex, body mass index, surgical approach, and year of surgery. At minimum 2-year follow-up, patient-reported outcomes (PROs) including Forgotten Joint Score (FJS), Modified Harris Hip Score (mHHS), Hip Disability and Osteoarthritis Outcome Score Pain (HOOS pain), and Visual Analog Pain Scale (VAS) were analyzed. Results Sixty-three hips in 60 patients (age: 47.3±9.4 years, BMI: 29.8±6.2 kg/m2) were matched to 252 THA-only hips, with patients converting to THA at a mean 3.1 years (range 0.3-10.3) following hip arthroscopy. While both HA-THA and THA patients demonstrated significant (p<0.001) postoperative improvements in PROs, HA-THA patients reported significantly lower postoperative FJS, mHHS, HOOS pain, and VAS pain scores (p<0.001) as compared to THA-only controls. At mean 6.6±3.2 years follow-up, HA-THA patients with preoperative Tönnis grades 2-3 reported significantly increased FJS, mHHS, and HOOS pain compared to those with preoperative Tönnis grades of 0-1 (p≤0.03). Additionally, HA-THA patients with preoperative Tönnis grades 0-1 exhibited worse PROs (p<0.001) as compared to THA-only controls. While there were no differences in complication rates between HA-THA patients and THA-only controls (8% vs. 5%, p=0.49), all-cause reoperation was greater amongst HA-THA patients compared to THA-only (10% vs. 2%, p=0.01). Conclusion While improved compared to preoperatively, patients undergoing THA after prior hip arthroscopy demonstrated inferior outcomes at mid-term follow up as compared to a demographically age-matched cohort without prior arthroscopy. When considering conversion to THA following arthroscopy, clinicians should consider counseling patients regarding improved outcomes in the setting of advanced radiographic osteoarthritis, and potentially increased all-cause reoperation.