Heterotopic Ossification After Total Hip Arthroplasty

Heterotopic ossification (HO), the development of bone outside its normal location in the skeleton, can compro­mise outcomes of total hip arthroplasty (THA). The etio­pathogenesis of HO, though incompletely understood, involves genetic abnormalities, neurologic injury, and musculoskeletal trauma. Several systems are used to classify severity of HO after THA. Numerous risk factors for HO, including patient factors and surgical techniques, have been described. Prophylaxis against HO tradition­ally has involved radiation therapy or use of nonsteroidal anti-inflammatory drugs. Once formed, heterotopic bone can be managed only with surgical excision.