Functional outcome following a locked fracture-dislocation of the calcaneus

Purpose Locked fracture-dislocations of the calcaneus are uncommon, and a substantial number of these injuries is not recognised or is misdiagnosed at first presentation. The primary aim of this study was to evaluate the long-term outcome in patients with this injury. Methods This is a retrospective cohort study of adult patients who sustained a uni- or bilateral calcaneal fracture-dislocation. Outcome was measured using validated questionnaires, including the American Orthopaedic Foot and Ankle Society Hindfoot score (AOFAS), Foot Function Index (FFI) and a visual analogue scale (VAS). Results During the 12-year study period a total of 16 patients with 17 locked fracture-dislocations were identified. This represented 6 % of all surgically treated calcaneal fractures (17 of 279). The median follow-up was 48 months. All patients were treated using an extended lateral approach and plate fixation. In one patient with a delayed presentation a primary arthrodesis was performed. The functional outcome scores were available for 14 patients with 14 fractures. The median AOFAS was 74 [interquartile range (IQR) 47-86], the median FFI was 18 (IQR 6-37) and the median VAS for overall satisfaction was 8.2 (IQR 5.5-9.4). A secondary fusion was deemed necessary in three cases. Conclusions This study shows that, with surgical treatment via an extended lateral approach, the outcome in patients with a locked fracture-dislocation of the calcaneus is similar to the outcome of other displaced intra-articular calcaneal fracture types. However, a higher rate of secondary subtalar fusion can be expected.