RANDOMIZED TRIAL COMPARING EARLY POSTOPERATIVE IRRADIATION VS. THE USE OF NONSTEROIDAL ANTIINFLAMMATORY DRUGS FOR PREVENTION OF HETEROTOPICOSSIFICATION FOLLOWING PROSTHETIC TOTAL HIP-REPLACEMENT

Purpose: A randomized trial was undertaken to assess the comparative e fficacy of early postoperative irradiation with either 5 or 7 Gy vs. t he use of nonsteroidal antiinflammatory drug (NSAID) for prevention of heterotopic ossification (HO) following prothetic total hip replaceme nt (THP), Methods and Materials: Between 1993 and 1994, 301 patients w ere randomized to receive postoperative irradiation (5 or 7 Gy) or NSA ID. One hundred and thirteen patients were treated with NSAID (indomet acin 2 x 50 mg/day for 1 week), 93 patients were irradiated with a sin gle 7 Gy fraction, 95 patients with a single 5 Gy fraction, The treatm ent volume included the soft tissues between the periactebular region of pelvis and the intertrochanteric portion of the femur, X-rays of tr eated hips were obtained immediately and 6 months after surgery, Heter otopic ossification was scored according to the Brooker Grading system , One hundred patients receiving no prophylactic therapy after total h ip arthroplasty between 1988 and 1992, were analyzed and defined as hi storical control group, Results: Incidence of heterotopic ossification was 16.0% in NSAID-group (Brooker Score I: 8.0%; II: 6.2%; III: 1,8%; IV: 0%), 30.1% in 5 Gy group (Brooker Score I: 24.7%; II: 4.3%; III: 1.1%; IV: 0%), and 11.1% in 7 Gy group (Brooker Score I: 11.6%; II: 0% ; III: 0%; IV: 0%), Regarding overall heterotopic ossification there w as a significant difference between the NSAID group and the 5 Gy group (p < .015), respectively, between the 7 Gy group and the 5 Gy group ( p < .0001). No significant difference was noted in the influence of ov erall HO between the NSAID and the 7 Gy group (p > 0.3). Analyzing the clinically significant HO (Brooker Score III and IV) patients irradia ted with 7 Gy developed less HO than those treated with NSAID (p = 0.0 03), Incidence of HO was greater in the untreated historical control g roup (Brooker Score I: 26%; II: 15%; III: 19%; IV: 5%) than in all thr ee prophylacticly treated groups. Conclusion: Prophylactic irradiation of the operative site after hip replacement with single a 7 Gy fracti on is the most effective postoperative treatment schedule in preventio n of clinically significant heterotopic ossification, This therapy mod ality is more effective than irradiation with a single 5 Gy fraction o r use of NSAID. (C) 1997 Elsevier Science Inc.