Functional outcomes of gluteus medius repair after prior primary THA: a case series with 2-year minimum follow-up.

PURPOSE: Degenerative gluteus medius (GM) pathology is a known contributor to lateral hip pain and functional deficits after total hip arthroplasty (THA). While concurrent GM repair at the time of THA has been described, outcomes of repair performed after THA remain limited. This study evaluated patient-reported outcomes (PROs), satisfaction, and complication rates following open GM repair after THA, with a minimum 2-year follow-up. METHODS: Prospectively collected data from a hip preservation registry were analysed for patients who underwent open GM repair after prior ipsilateral THA between February 2015 and June 2022. Inclusion required preoperative and ⩾2-year follow-up scores for the modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (iHOT-12), visual analogue scale (VAS) for pain, and satisfaction. Exclusion criteria were prior GM repair, revision THA, additional concomitant procedures, or open workers' compensation claims. Minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) rates were calculated. RESULTS: 16 patients met criteria: 14 (87.5%) had complete follow-up at a mean of 55.4 ± 27.2 months. Mean age was 68.1 ± 9.4 years, and 64.3% were female. Tear patterns included low-grade partial (7.1%), high-grade partial (57.1%), and full-thickness (35.7%); 35.7% had gluteus minimus involvement. Significant improvements were observed in mHHS (44.3 ± 14.3 to 71.9 ± 16.4, Δ = 27.6 ± 20.7, p < 0.01), iHOT-12 (24.7 ± 12.2 to 57.5 ± 24.5, Δ = 32.8 ± 27.9, p < 0.01), and VAS (5.7 ± 2.7 to 2.6 ± 2.0, Δ = -3.1 ± 3.2, p = 0.01). Mean satisfaction was 7.2 ± 3.2. 1 patient (7.1%) required revision GM repair; no THA implant revisions were done. CONCLUSIONS: GM repair following THA was associated with favourable outcomes, high satisfaction, and low re-operation rates at mid-term follow-up. A high proportion of patients achieved clinically meaningful improvements, supporting the role of GM repair as an effective intervention for abductor pathology after THA.