Heterotopic ossification after total hip arthroplasty (THA) in congenital hip disease: comparison of two different prophylactic protocols

Introduction  We aimed to evaluate retrospectively the efficacy of combined postoperative radiotherapy and indomethacin compared to indomethacin alone for the prevention of heterotopic ossification (HO) in high-risk patients with congenital disease of hip (CDH) undergoing total hip arthroplasty (THA). Materials and methods  Fifty-five patients received indomethacin alone (Group A), while 44 patients received the combined protocol (Group B). Patients ≥55 years were enrolled in Group B and those younger than 55 years in Gro up A. Patients were evaluated radiologically for the pre sence of HO 6 months after the operation. Results  The incidence of HO in Group A was 34.5% (95% confidence interval 22.2–48.6%), while the respective incidence in Group B patients was 27.3% (95% CI 15.0–42.8%). The difference was not statistically significant (p=0.5). No significant treatment-related side effects were reported. Conclusions  This is the first study evaluating the impact of HO prophylaxis in an immiscible population of patients with secondary arthritis due to CDH undergoing THA. Further future randomised evidence is required in order to ascertain the observed trend towards improved efficacy of the combined protocol for HO development.