Forty-four fractures of the acetabulum that had been treated with open
reduction and internal fixation necessitating dissection of the gluteal
muscles were reviewed radiographically for the development of heterotopic
bone. Grade-2 (Brooker classification) or more severe heterotopic
ossification was seen in thirteen (50 per cent) of twenty-six patients who
did not receive indomethacin but in only one (5.5 per cent) of eighteen
patients who received indomethacin for six weeks postoperatively. In the
patients who did not receive indomethacin, the maximum amount and extent of
the heterotopic bone was evident in twelve weeks. In the patients who did
receive indomethacin, the heterotopic ossification did not progress after
the administration of indomethacin was discontinued. We concluded that, in
patients who have a fracture of the acetabulum, indomethacin provides
effective prophylaxis for heterotopic bone after operative reduction with
gluteal dissection.