Heterotopic bone formation following hip arthroplasty: A retrospective study of 65 bilateral cases

Abstract

Heterotopic bone formation after two-stage bilateral cemented total hip arthroplasty was evaluated in 65 patients (23 women and 42 men) who had not received treatment with anti-inflammatory drugs in the immediate postoperative weeks. The mean age at the first operation was 65 years, and the median interval between the two arthroplasties was 3 months. Fifty-two patients developed heterotopic ossification after the initial hip arthroplasty. Of these patients, 40 also developed ossifications after contralateral hip arthroplasty. Out of 11 males developing Grade-III heterotopic ossification after the initial hip arthroplasty, 8 also developed Grade-III ossification after contralateral hip arthroplasty. Two females developed Grade-III ossification after the initial arthroplasty, but neither of them developed a Grade-III lesion after contralateral total hip arthroplasty. Males with Grade-III heterotopic ossification after the initial hip arthroplasty were shown to be at a high risk of developing the same severe lesion after contralateral total hip arthroplasty, making them candidates for postoperative prophylaxis.