No difference between two doses of diclofenac in prophylaxis of heterotopic ossifications after total hip arthroplasty

BACKGROUND: In a monocentric, randomized, placebo-controlled double-blind study, we investigated the efficacy of two doses of diclofenac-cholestyramine for the prevention of heterotopic ossification (HO). PATIENTS: The study comprised 245 patients undergoing total hip arthroplasty (THA). RESULTS: With 150 mg cholestyramine-bound diclofenac (2 x 1 capsule Voltaren resinate) daily during a postoperative period of 14 days, 19% of patients showed slight HO (Brooker grade 1), and no patient had more severe ossifications (grades 2-4). In the group receiving 75 mg daily (1 x 1 capsule), 17% of patients showed grade 1 HO and 4% grade 2 HO. No patient had grades 3-4 HO. No differences in clinical results were seen between the two groups 6 months after THA. INTERPRETATION: Since the rate of adverse gastrointestinal events was lower (23% versus 38%, p = 0.02) in the group receiving the lower dose, we recommend it.