Functional outcome of excision of heterotopic ossification after total hip arthroplasty.

Fifty-three cases of symptomatic heterotopic ossification were evaluated after total hip arthroplasty for the specific purpose of determining the value of surgical excision without revision or other concurrent procedures. The mean followup was 3.5 years for range of motion and 7.8 years for radiographic evaluation. A statistically significant increase in range of motion was obtained for the group at final followup. The mean increase in flexion arc was 34 degrees, abduction and adduction arc was 22 degrees, and rotation arc was 21 degrees. Of the patients who underwent surgical excision of heterotopic bone solely because of pain, none had complete alleviation of symptoms. It is concluded that surgical excision of heterotopic bone results in significant improvement in functional outcome, but it cannot be expected to predictably alleviate pain. Finally, the ultimate arc of motion was better than that suggested radiographically by the Brooker classification system.