[Prevention of periarticular ossification--with results of a randomized, double-blind study comparing acemetacin versus indomethacin].

We examined the effect of NSAR in the prophylaxis of heterotopic ossifications after hip arthroplasty. During a randomized doubleblind study 59 patients took Indometacin and 60 patients Acemetacin for three weeks after the operation. All of them got a thrombosis prophylaxis with Heparin and a short term antibiotic prophylaxis. The range of ossifications was checked three months after the operation according to Arcq. The proportion of patients with no clinical symptoms (grade 0 or 1) was 92.3% in the indometacin group and 98.2% in the acemetacin group. Because of side effects (mainly gastrointestinal) 7 patients (11.9%) in the indometacin group and 5 patients (8.3%) in the acemetacin group stopped the study. In a previous study we had examined the effect of thrombosis prophylaxis by Heparin on the heterotopic ossifications. These results could now be taken for comparison. According to these results the examined NSAR Indometacin and Acemetacin raised the group of low grade heterotopic ossifications. The higher grades (2 degrees and 3 degrees according to Arcq) were only be seen in less than 5%. That is why we recommend the NSAR (Acemetacin or Indometacin) generally after hip arthroplasty as prophylaxis of heterotopic ossifications.