(grade I: 22, grade III: 2 and grade IV: 1). In the

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 H