Subtalar Dislocation: Case Report and Review of Literature

Special Article - Subtalar Dislocation

Austin Surg Case Rep. 2017; 2(2): 1020.

Subtalar Dislocation: Case Report and Review of Literature

Dinesh Dhar*

Senior Specialist Orthopedics, Nizwa Regional Referral Hospital, Oman

*Corresponding author: Dinesh Dhar, Senior Specialist Orthopedics, Nizwa Regional Referral Hospital, Oman

Received: November 20, 2017; Accepted: December 04, 2017; Published: December 11, 2017

Abstract

Subtalar Dislocations (SD) is unusual injuries usually associated with fractures of talus, calcaneum and fifth metatarasal. Isolated subtalar dislocation is very rare. Four types have been described medial, lateral, posterior and anterior. A rare case of closed lateral subtalar dislocation in a 23 years old male patient following motor vehicle accident is reported. It was treated successfully by closed reduction and immobilization in below knee cast with good functional outcome. The management of the case with recent review of literature on the subject has been discussed.

Keywords: Subtalar; Dislocation; Lateral; Isolated

Introduction

Isolated subtalar dislocation is very rare injuries and very few cases have been reported in the English literature. Strong ligament connecting talus with calcaneum along with strong joint capsule and biomechanics of ankle joint make this injury unusual [1]. Subtalar dislocation involves simultaneous disruption of talocalcaneal and talonavicular joints while tibiotalar and calcaneocuboid joints remain intact. Patients with bony or soft tissue aplasia around ankle joint are more likely to suffer isolated subtalar dislocation [1]. The foot along with calcaneum can dislocate medially, laterally, posteriorly or anteriorly in relation to talus. This case report describes the mechanism, pattern of injury and management of case, highlighting good functional outcome after closed reduction immobilization and good postoperative rehabilitation programme.

Case Presentation

23 years male patient involved in motor vehicle collision was referred from peripheral health centre with trauma to left ankle. He was seen in accident and emergency by on call orthopedic team and noticed to have gross swelling all around left ankle and foot with deformity. Dorsalis pedis and posterior tibial pulsations were not felt but patient had capillary circulation of toes with intact sensations. Radiographs (AP, Lateral) of ankle, foot revealed dislocation of talaonavicular and talocalcaneal joints with prominence of talar head dorsomedially and calcaneum laterally without any associated fractures and diagnosis of isolated lateral subtalar dislocation was made (Figure 1,2,3).

Under sedation successful closed reduction of subtalar dislocation was done in emergency by on call orthopedic team and left foot and ankle was immobilized initially in posterior plaster slab for period of 05 days, followed by below knee scotch cast for 05 weeks (Figure 4,5). After reduction posterior tibial and dorsalis pedis pulsations were well felt. The patient went on to start partial weight bearing at 05 weeks with active and passive range of motion exercises of left ankle under physiotherapist guidance and full weight bearing by 9 weeks post injury (Figure 6).

Discussion

Subtalar dislocations are very rare injuries and account for 1-2 percent of all foot dislocations [2]. Majority of cases are reported in third decade of life with M: F ratio of 6:1. The mode of injury is commonly high energy traumas motor vehicle accidents, sport injuries [3]. Associated fractures of talus or fifth metatarsal have been reported. Subtalar dislocation was classified initially by Broca (1853) into three types: Medial, lateral and posterior dislocations. Malgaigne and Buerger (1856) described an additional anterior dislocation. Medial dislocation comprises 80-85% followed by lateral 15-20%, posterior and anterior 1-2%.

The medial subtalar dislocation also referred to as acquired clubfoot results from forceful inversion of forefoot with resultant stress on lateral collateral ligaments which along with talocalcaneal and talonavicular ligaments rupture resulting in subtalar dislocation with talus remaining in its normal position. The lateral subtalar dislocation also referred to as acquired flatfoot results from forceful eversion of foot with talus pivitoning on anterior calcaneus process. The posterior and anterior types results from extreme forceful plantar flexion or dorsiflexion of forefoot [1]. Lateral subtalar dislocation results from high energy trauma and have poor prognosis in the long run compared to medial subtalar dislocation [2]. Associated osteochondral shearing injuries to articular surface of talus, calcaneus or navicular are common up to 45% however they are difficult to be seen on plain radiographs.