The relationship between chronic ankle instability and variations in mortise anatomy and impingement spurs

Thirty-five patients undergoing a Brostrom procedure for ankle instability were studied retrospectively as to the presence or absence of spurs and loo se bodies, outcome, and mortise relationships. 100 adult volunteers had the ir ankles radiographically and clinically examined for spurs, loose bodies, and laxity. 100 patients' ankles with computed axial tomography were exami ned to define malleolar relationships. The AOFAS Hindfoot scores on the Brostrom patients with or without spurs we re not different. Patients undergoing a Brostrom procedure had a 3.37 times incidence of spurs and/or loose bodies compared to normal adult population . The incidence of asymmetric but asymptomatic ankle laxity in normal adult s was 11%, The fibula has a 38 degrees range of position relative to the ax is of the talus and the medial malleolus. A posterior fibular position may predispose to injury.