Introduction: Recent reports have suggested that selective COX-2 inhibition may be sufficient for the prevention of heterotopic ossification.
Methods: We performed a randomized controlled study to evaluate the effect of the selective COX-2 inhibitor rofecoxib compared to that of indomethacin on the incidence and extent of heterotopic ossification in patients who had undergone hip replacement surgery. 50 patients received a daily dose of 25 mg rofecoxib and 50 patients received a daily dose of 100 mg indomethacin (25, 25, and 50 mg).
Results: No ossifications were found in 48 patients. Grade-II ossifications were seen in 5/46 patients in the rofecoxib group and in 6/50 patients in the indomethacin group. Grade-III and grade-IV ossifications were seen in 3/46 patients in the rofecoxib group only. The differences were not statistically significant. The study medication had to be discontinued in 2 patients in the indomethacin group, due to dyspepsia.
Interpretation: After short-term administration, the selective COX-2 inhibitor rofecoxib was effective in preventing heterotopic ossification after total hip arthroplasty.