Medial subtalar dislocation from a low-energy trauma. A case report and review of the literature

Abstract

Introduction: Subtalar dislocation is a rare injury characterized by a simultaneous dislocation of the talocalcaneal and talonavicular joints. The most common type is caused by high-energy trauma with medial dislocation of the foot. This injury is frequently associated with fractures, but isolated dislocations are also reported.

Case presentation: We report a rare case of medial subtalar dislocation secondary to low-energy injury in a 61-year-old woman. Following X-rays and CT scan, prompt closed reduction was performed under sedation and, after reduction, X-rays showed a good realignment of the foot. The CT scan revealed an occult non-displaced fracture of the posterior part of the talus. The patient was managed conservatively by a non-weight bearing cast for four weeks, followed by a rehabilitation program. At follow-up, six months later, we observed a good clinical and radiographic result.

Discussion: The reported case confirms that the mechanism of injury is an important factor in predicting the final result, since subtalar dislocations secondary to a high-energy trauma are often associated with significant complications. We believe, in agreement with other authors, that a low-energy trauma generally doesn't produce long-term morbidity. Prompt reduction is very important in order to minimize soft tissue and neurovascular complications, although a CT is recommended to identify occult fractures.

Conclusion: Subtalar dislocations, caused by low energy trauma, if adequately reduced in the emergency room, generally heal with conservative treatment, reducing the risk of significant complications. However, since we report a single patient, further case analysis is needed to make solid conclusions.

Keywords: Low energy trauma; Medial subtalar dislocation; Subtalar dislocation; Subtalar joint; Talonavicular joint.

Fig. 1

Clinical and radiographic views of a closed medial subtalar dislocation of the right foot in a 61-year-old patient.

Fig. 2

CT of the ankle and the foot with 3D reconstruction confirmed the diagnosis, but showed an associated undisplaced fracture of the posterior part of the talar bone (arrow).

Fig. 3

Radiographic examination of the subtalar joint after closed reduction and casting.

Fig. 4

The radiographic examination performed at follow-up, six months later, showed a stable anatomic reduction. The patient was pain free with ankle and foot range of motion comparable to the unaffected contralateral side.