Heterotopic ossification prophylaxis after hip arthroscopy: a retrospective comparative study of acemetacin and indomethacin

Abstract The aim of this study was to compare the efficacy and safety profiles of acemetacin and indomethacin for prophylaxis of heterotopic ossification (HO) following hip arthroscopy. While indomethacin is a well-established agent, evidence on acemetacin remains limited. This retrospective study included 114 hips of 110 patients who underwent hip arthroscopy for femoroacetabular impingement between September 2022 and September 2024. Patients received indomethacin or acemetacin for 3 weeks postoperatively. HO development was assessed radiologically using the Brooker classification. Functional outcomes and non-steroidal anti-inflammatory drug-related adverse events were recorded and compared. HO developed in 6 hips (5.3%): 4 in the indomethacin group (8%) and 2 in the acemetacin group (3.1%) (P = .402). All HO cases were Brooker grade 1 or 2. Gastrointestinal adverse events occurred more frequently in the indomethacin group (16%) compared to the acemetacin group (4.7%) (P = .042). No significant differences were found between groups regarding demographic data, functional scores, or laboratory parameters. Among the variables analysed, a higher number of suture anchors used during labral repair was the only factor significantly associated with HO development (P = .023). No significant differences in functional scores were observed between HO and non-HO patients, though scores tended to be higher in the non-HO group. Both acemetacin and indomethacin are effective for HO prophylaxis after hip arthroscopy. However, acemetacin was associated with fewer gastrointestinal adverse events, suggesting it may be a more tolerable alternative. Given the retrospective design and low event rate, larger prospective trials are required to validate these findings.