Heterotopic ossification

Heterotopic ossification. The dense bone in the soft tissues around the right hip in this patient, indicated by the arrows on radiograph and CT, is called ‘heterotopic ossification’. This can develop after direct trauma to the soft tissues that are involved, including after hip surgery, but, somewhat bizarrely, can also develop as a result of a head injury or other neurological insult, or as a consequence of prolonged immobilization such as due to paraplegia. In severe cases, the new bone can result in complete fusion of the hip.