Heterotopic Ossification - Causes

Causes

Heterotopic ossification of varying severity can be caused by surgery or trauma to the hips and legs. About every third patient who has total hip arthoplasty (joint replacement) or a severe fracture of the long bones of the lower leg will develop heterotopic ossification. Between 50% and 90% of patients who developed heterotopic ossification following a previous hip arthoplasty will develop additional heterotopic ossification.

Heterotopic ossification often develops in patients with traumatic brain or spinal cord injuries, other severe neurologic disorders or severe burns, most commonly around the hips. The mechanism is unknown. This may account for the clinical impression that traumatic brain injuries cause accelerated fracture healing.

There is another variant called myositis ossificans progressiva, a rare, genetic disorder, in which there are recurrent episodes of inflammation around the big toe, which eventually lead to ossification in the area and deformity of the toe.