Preliminary study of rofecoxib (25 mg) in prevention of heterotopic ossification after total hip replacement

Heterotopic ossification is a well-known complication of surgical approaches to the hip that involve dissection of the gluteal muscles. Heterotopic ossification has been reported as an incidental finding on radiographs of as many as 84% of patients who have had total hip arthroplasty. This study evaluated the possibility of using rofecoxib, a COX II selective inhibitor, to prevent heterotopic bone formation after total hip replacement. Sixty consecutive patients operated by the same surgeon, using the same surgical approach (lateral approach) for total hip replacement and who were considered to be at risk for postoperative heterotopic ossification, were enrolled into this prospective study. The patients were randomly assigned to one of two treatment groups: group 1 received rofecoxib (25 mg) daily from the day after total hip replacement for three weeks; group 2 received no pharmacological treatment. The two groups were clinically and radiographically controlled at 3-monthly intervals up to 1 year after surgery with a minimum follow-up of 6 months. Three patients in group 1 were lost to follow-up and consequently were not considered in the final evaluation. In group 1, 14 patients (51.9%) showed no ossification, 9 (33.3%) showed Brooker grade I ossification, 4 (14.8%) showed grade II ossification, and no patients with grades III and IV were detected. In group 2, 15 (50.0%) of the patients showed no ossification, 6 (20.0%) showed grade I ossification, 5 (16.7%) showed grade III ossification, and no patient with grade IV ossification was detected. The difference between the two treatment groups regarding extent of heterotopic ossification was statistically significant (p=0.028) and consequently gives a rational basis for a larger successive study.