Indomethacin for prevention of heterotopic ossification after total hip arthroplasty

Twenty-four patients (29 hips) undergoing total hip arthroplasty were routinely given 75 mg of indomethacin daily for 4 weeks after operation and reviewed radiographically for heterotopic ossification (HO) for a minimum of 6 months. A comparison group of 25 patients (27 hips) without indomethacin treatment was formed and studied in the same manner. This group of patients received the usual postoperative analgesic treatment, which is diclofenac sodium twice daily parenterally for 5-10 days. The indomethacin group also received the same treatment. In the indomethacin group no patient had grade II, III, and grade IV HO and the incidence of grade I HO was 31% (nine patients). In the comparison group one patient (3%) had grade I, three (11%) grade II, and eight (30%) grade III HO. These findings suggested that indomethacin effectively prevented higher grades of HO following total hip arthroplasty. Two patients not included in the study had gastrointestinal bleeding and recovered after withdrawal of the drug.