Randomized trial comparing preoperative irradiation versus the use of non-steroidal-antiinflammatory drugs for prevention of heterotopic ossification following prosthetic total hip replacement

Purpose: In vivo data support the effectiveness of early preoperative irradiation within 4h before operation in suppressing the development of heterotopic ossification (HTO) after total hip replacement (THR). This procedure can entail logistical difficulties. A randomized trial was undertaken to assess the efficacy of late preoperative irradiation in the evening before the day of operation compared with the use of non-steroidal-antiinflammatory drugs (NSAID). Methods: Between 1995 and 1996 103 patients with normal risk factors for HTO following elective hip replacement were randomized to receive preoperative irradiation (single 7Gy fraction) or NSAID (diclofenac-colestyramin). X rays of treated hips were obtained immediately and 6 months after surgery. HTO was scored ascending to the Brooker grading system. A group of 100 patients, who received no prophylactic therapy after THR between 1988 and 1992, were analysed as untreated historical control group. Results: The incidence of HTO was 48% in the irradiation-group (Brooker Score I:52%; II:36%; III:5%; IV:0%), 9,3% in the NSAID-group (Brooker Score I:7,5%; II:1,8%; III:0%; IV:0%) and 65% in the untreated control group (Brooker Score I:26%; II:15%; III:19%; IV:5%). Regarding overall HTO there was a significant difference between the two treatment groups. Analysing the clinically significant HTO (Brooker score III or IV) no significant difference was noted between irradiated patients and patients treated by NSAID, but between the treatment groups and the untreated historical control group. Conclusion: NSAID and late preoperative irradiation can reduce the incidence of clinical significant HTO after THR. with a single 5Gy fraction or use of NSAID