Short-term treatment with nonsteroidal antiinflammatory medications to prevent heterotopic bone formation after total hip arthroplasty. A preliminary report.

The effect of short-term postoperative treatment with nonsteroidal antiinflammatory medication to prevent the formation of heterotopic ossification (HO) after total hip arthroplasty (THA) was studied in two groups of patients. Group A included 46 noncemented THAs in 40 men. Eight patients (13 hips) received prophylaxis with 25 mg of indomethacin three times daily for 14 days, and 32 patients (33 hips) received prophylaxis of 650 mg of aspirin twice daily for six weeks. Six to 12 months after surgery, only one hip (aspirin treated) developed HO, this being Grade I. In group B, 17 hips in 17 patients with cemented THA received prophylaxis of 25 mg of indomethacin three times daily. Of these, 12 patients were given indomethacin from one to nine days. One year after surgery, five hips had no HO and seven hips showed a Grade I or Grade II lesion. The remaining five patients in Group B received indomethacin from 19 to 26 days; one developed HO. This study demonstrated that treatment with either 650 mg of aspirin twice daily for six weeks or 25 mg of indomethacin three times daily for the first 14 postoperative days is sufficient to prevent the formation of severe HO after THA.