Indomethacin for prevention of ectopic ossification after hip arthroplasty.

Twelve patients at risk of developing postoperative para-articular ossifications were treated with indomethacin. Ossification after previous total hip arthroplasty was excised in eight patients. Four patients had ossification in the opposite hip after previous arthroplasty. Five patients in whom ectopic ossification was excised developed recurrences of lesser degree than the primary ossifications. One patient with the condition in the opposite hip developed ossification. No patients complained of stiffness in the hip and all had markedly increased hip motion. Indomethacin seems to be valuable as prophylaxis in patients at risk of developing ectopic ossification and as a supplement to secondary excision.