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.

Injuries Associated to Subtalar Dislocation: A Systematic Review

“…Mechanism of subtalar dislocation is trauma to a plantar-flexed foot either in inversion, resulting in medial subtalar joint dislocation (80%), or eversion, resulting in lateral dislocation (17%); while anterior or posterior dislocations are rare (5,6). The diagnosis of subtalar dislocation is usually made on anterior-posterior (AP), lateral, and oblique radiographs of the foot or ankle (7). The nature of the deformity often limits radiographic positioning (7).…”

“…The diagnosis of subtalar dislocation is usually made on anterior-posterior (AP), lateral, and oblique radiographs of the foot or ankle (7). The nature of the deformity often limits radiographic positioning (7). After reduction, AP and lateral radiographs of the foot as well as AP and mortise views of the ankle are obtained to confirm optimal results (7).…”

“…The nature of the deformity often limits radiographic positioning (7). After reduction, AP and lateral radiographs of the foot as well as AP and mortise views of the ankle are obtained to confirm optimal results (7). In the absence of deformity, post-reduction radiographs are usually of better quality than those obtained at the time of injury and associated fractures become more apparent (2).…”

“…The majority of subtalar dislocations are accompanied by fractures of the hindfoot, including osteochondral fractures, calcaneus fractures, and fractures of the posterior process and tubercles of the talus (7). Intra-articular osteochondral fractures are especially common, occurring in 50%-71% of all subtalar dislocations and up to 100% of lateral dislocations (2), the majority of which involve the subtalar joint (8).…”