Severe heterotopic ossifications after Rockwood type II acromioclavicular joint injury: a case report

Heterotopic ossification (HO) is a benign condition of abnormal bone formation in soft tissue. It is frequently asymptomatic, though it manifests as decreased range of motion in the affected joints that may occur in the shoulder after a substantial traumatic injury and can complicate the functional outcome of the affected upper extremity. However, severe HO is an extremely rare event following acromioclavicular joint (ACJ) injury.

We are presenting a case of a 29-year-old male patient who had a trauma with resultant Rockwood type II injury. He subsequently complained of left shoulder pain with decreased range of motion 3 years later. HO was diagnosed after X-rays and the severity was assessed with a computerized tomography scan and magnetic resonance imaging. The patient was treated with a combination of pre-operative radiotherapy, surgical excision, mobilization under anesthesia, non-steroidal anti-inflammatory drug (NSAID) therapy and physiotherapy.

At 6-month follow-up, excellent clinical and radiological outcomes were achieved with a Constant score of 92 points, DASH score of 24%, and ASES score 100%, with a full range of motion of the left shoulder. Furthermore, there was no more radiological evidence of HO on plain radiographs.

Severe heterotopic ossification after a Rockwood type II ACJ injury in this case was successfully treated with combination of pre-operative radiotherapy, surgical excision and manipulation under anesthesia as well as NSAID therapy and physiotherapy.