Subtalar dislocations: Mechanisms, clinical presentation and methods of reduction

Abstract

Subtalar joint is a complex joint in hindfoot formed by the talus superiorly and the calcaneus and navicular inferiorly. Subtalar dislocations are high-mechanism injuries, which are caused by simultaneous dislocation of both talonavicular and talocalcaneal joints, without major fracture of the talus. They are usually classified as medial (most common), lateral, anterior and posterior dislocations, based on the position of foot in relation to talus and the indirect forces that have been applied to cause this significant injury. They are usually diagnosed by X rays, but computed tomography and magnetic resonance imaging can be used to identify associated intra-articular fractures and peri-talar soft tissue injuries respectively. Majority being closed injuries, can be managed in ED by closed reduction and cast immobilisation, but if they are open, have poor outcomes. Complications that ensue open dislocations are post-traumatic arthritis, instability and avascular necrosis.

Keywords: Joint; Subtalar; Joint dislocations; Flatfoot; Clubfoot; Talus

Core Tip: Subtalar dislocations are rare, high mechanism injuries. Comprehensive trauma assessment, along with limb specific assessment is the key approach to deal with these injuries. Lateral dislocations constitute for open injuries commonly, and must be managed according to the BOAST-Open fracture guidelines. Avascular necrosis of the talus due to injury to the canalis tarsi artery, are troublesome complication. Thus, one needs to have high index of suspicion when the dislocation is open or associated with talus fracture.