Syndesmosis sprains of the ankle. The influence of heterotopic ossification.

A retrospective study of 50 syndesmosis sprains in 44 football players was performed. Five patients (6 ankles) were lost to follow-up, allowing review of 44 injuries. Average follow-up was 47 months. The patients were evaluated for recurrent injury, overall ankle function, and for persistent ankle symptoms, including stiffness, pain, limping, and swelling. Follow-up radiographs of the injured ankle were obtained in 22 patients. The average return time to full activity was 31 days. Pain with pushing-off was a major factor preventing return to activity. At final followup, 36% of the patients complained of persistent mild to moderate stiffness of the ankle. Twenty-three percent had mild to moderate pain, usually with activity. One patient had a mild limp with activity, and 18% of the ankles had persistent mild to moderate swelling. Ankle function was rated as good to excellent in 86%. All patients with fair results had recurrent ankle sprains. There were no poor results. Eleven of the 22 patients with follow-up radiographs developed heterotopic ossification within the interosseous membrane, but no patient developed a frank synostosis. The patients with heterotopic ossification required an average of 11 days more recovery time than those without ossification. There was no significant difference between the 2 groups' ultimate ratings of ankle function or ankle symptoms, but the ankles with heterotopic ossification were associated with more recurrent lateral ankle sprains. We conclude that syndesmosis sprains require a longer recovery period than other types of ankle sprains. Most of these injuries showed good to excellent ankle function after recovery, unless there was a recurrent ankle sprain.2+ formation of heterotopic ossification.