Proximity of the Lateral Talar Process to the Lateral Stabilizing Ligaments of the Ankle and Subtalar Joint

Abstract

Fractures of the lateral process of the talus have become more frequent as the sport of snowboarding has gained popularity. The anatomy of the ligamentous attachments to the process has been described, but ligament proximity to the lateral talar process has never been specified. The objective of this cadaver study was to measure the proximity of the lateral talar process to the various lateral stabilizing ligaments of the ankle and subtalar joint: the anterior talofibular ligament, lateral talocalcaneal ligament, posterior talofibular ligament, interosseous ligament, cervical ligament, and lateral root of the extensor retinaculum. After thawing, all musculotendinous structures from 10 fresh-frozen cadaver lower limbs were carefully removed and the distal fibula was reflected to enable adequate exposure of the lateral talar process and ligamentous attachments. The apex of the lateral process was defined. Subsequently, the distance from the apex to the nearest edge and center of these surrounding ligaments was independently measured by two examiners. The average apex-edge distances were 9.3 mm (posterior talofibular); 8.7 mm (anterior talofibular), 3.4 mm (lateral talocalcaneal), 13.9 mm (interosseous), 19.1 mm (cervical), and 13.0 mm (lateral root of extensor retinaculum). The average apex-center distances for those ligaments found to actually insert on the lateral talar process were 18.0 mm (posterior talofibular), 15.7 mm (anterior talofibular), and 6.2 mm (lateral talocalcaneal). Contrary to previous reports, our cadaver dissections identified that only three ligaments attach to the lateral process of the talus: lateral talocalcaneal, anterior talofibular, and posterior talofibular. Familiarity with these anatomic relationships may help guide the clinical treatment of lateral talar process fractures.