Prophylaxis for heterotopic ossification after primary total hip arthroplasty. A cohort study between indomethacin and meloxicam.

The authors have conducted a prospective cohort study of the efficacy of a 7 days administration of Indomethacin (n = 89) versus Meloxicam (n = 92), in the prophylaxis of heterotopic ossification (HO) in primary total hip arthroplasty. To assess the interobserver variability of the Brooker classification, all radiographs were evaluated by three investigators. In the Indomethacin group 25 patients developed HO (grade I: 22, grade III: 2 and grade IV: 1). In the Meloxicam group 34 developed HO (grade I: 30, grade II: 1 and grade III: 3). We were not able to show any difference between Indomethacin and Meloxicam in preventing heterotopic ossification after primary hip arthroplasty. We found a high interobserver variability in the grading system according to Brooker, in particular for the higher grades(grade II, III and IV).