Total Hip Arthroplasty for Patients Who Have Ankylosing Spondylitis: Is Postoperative Irradiation Required for Prophylaxis of Heterotopic Ossification?

Postoperative radiation for prevention of heterotopic ossification (HO) has been proven effective for the patients with ankylosing spondylitis (AS) after total hip arthroplasties (THA). This study aims to evaluate the effect of postoperative radiation in HO formation following THA in patients with AS. We retrospectively reviewed 129 hips from 91 patients with AS receiving primary THA from July 2004 to December 2012. There were total 38 patients (53 hips) did not receive postoperative prophylaxis in Group I. Moreover, 53 patients (76 hips) received postoperative single-fraction radiotherapy of 500 cGy in Group II. After a minimum 12-month follow-up, there was no significant difference in HO formation between the two groups (P = 0.210). This study suggests that postoperative radiation may not be necessary in Asian patients.