Rofecoxib inhibits heterotopic ossification after total hip arthroplasty

INTRODUCTION: Nonsteroidal anti-inflammatory drugs (NSAIDs) prevent heterotopic ossification but gastrointestinal complaints are frequently. Selective cyclooxygenase-2 (COX-2) inhibiting NSAID produce less gastrointestinal side effects. PATIENTS AND METHODS: A prospective two-stage study design for phase 2 clinical trials with 42 patients was used to determine if rofecoxib (a COX-2 inhibitor) 50 mg oral for 7 days prevents heterotopic ossification. A cemented primary THA was inserted for osteoarthroses. After 6 months heterotopic bone formation was assessed on AP radiographs using the Brooker classification. RESULTS: No heterotopic ossification was found in 81% of the patients, 19% of the patients had Brooker grade 1 ossification. CONCLUSION: Using a two-stage study design for phase 2 clinical trials, a 7-day treatment of a COX-2 inhibitor (rofecoxib) prevents effectively the formation of heterotopic ossification after cemented primary total hip arthroplasty.