Heterotopic ossification in patients after total hip replacement.

Heterotopic ossification (HO) is defined as pathological bone formation in soft tissues, for example in muscles, where physiologically there is no osseous tissue present. It is one of the most common complications of total hip joint replacement surgery. A wide variety of risk factors for heterotopic ossification have been identified to date. Almost 90% of total hip arthroplasty patients are at high risk for HO. There are two primary methods of preventing heterotopic ossification: pharmacotherapy with NSAIDs (non steroid anti-inflammatory drugs) and radiotherapy. Symptomatic heterotopic ossifications are treated by extracorporeal shock wave therapy (ESWT) and surgery, followed by NSAID pharmacotherapy or radiotherapy. The arterioles adjacent to areas of heterotopic ossification are usually embolized prior to the operation. This article describes the state of the art in the prevention and treatment of heterotopic ossifications based on the available literature.