A Challenging Case of a Compound Calcaneum Fracture With Lateral Subtalar Dislocation Managed by Primary Subtalar Fusion: A Case Report.

Calcaneal fracture dislocations are relatively uncommon. Locked fracture dislocations of the calcaneus are particularly rare and often missed during initial evaluation due to subtle radiographic signs. As a result, many patients are initially treated symptomatically with rest and analgesics. Persistent pain and impaired function usually prompt further outpatient evaluation, leading to delayed diagnosis. This delay increases the risk of complications such as malunion and post-traumatic arthritis. Here, we present a case we managed, along with insights into the effective management of such complex injuries. A 14-year-old girl presented with persistent left foot pain, back pain, and inability to bear weight on the left foot for one week after a fall from a height. Examination revealed a 10 cm × 7 cm wound over the medial aspect of the foot, heel tenderness, and tenderness over the L4-L5 spinous processes. Imaging showed a calcaneal fracture with lateral subtalar dislocation and an L4-L5 compression fracture. After wound debridement and negative-pressure therapy, surgery was performed using a lateral extensile approach. Primary subtalar fusion with three 4.5 mm screws and K-wire stabilization of the talonavicular joint was performed. At six months, radiographs confirmed fusion, and the patient returned to normal, pain-free function. Primary subtalar fusion can serve as an effective treatment option in cases of open calcaneal fractures associated with subtalar dislocation, particularly when articular cartilage viability is compromised and joint preservation is not feasible. By addressing instability and preventing long-term pain from post-traumatic arthritis, fusion provides a stable and functional foot. However, because evidence is limited, further research with larger patient cohorts and long-term follow-up is essential to establish clear indications, functional outcomes, and potential complications. This will help define the precise role of primary subtalar arthrodesis in managing these complex injuries.