The combined talus and sustentaculum fracture: A case series

Background: The sustentaculum tali is a biomechanically important stabilizer of the hindfoot and contributes to articular congruency of the subtalar joint. Sustentaculum injury associated with a talus fracture has been described infrequently and treatment of this combined injury varies. The purpose of this study was to describe and evaluate the outcomes of the combined talus and sustentaculum fracture.

Methods: Retrospective chart and radiographic review was performed on all talus fractures (n = 436) requiring operative fixation over a 21-year period at a single Level-1 trauma center. All talus fractures with sustentaculum fractures were included. Statistical analysis was performed using Chi-squared and Fishers exact tests where appropriate.

Results: Sustentaculum fractures occurred in 6.2 % (n = 27) of patients with talus fractures. Average follow-up was 14 months; 18.5 % were open fractures, 88.8 % were from high-energy mechanisms, and 44.4 % were polytraumas. Diagnosis of the sustentaculum fracture was missed on presenting radiographs in 69.2 % (n = 18). The most common associated talus fracture was a talar neck fracture (40.7 %) and the majority (73.7 %) were Hawkins II. Overall, 40.7 % (n = 11) of the sustentaculum fractures were treated with independent fixation and 7.4 % (n = 2) were treated with acute subtalar arthrodesis. Subtalar post-traumatic osteoarthritis (PTOA) at final follow-up was seen in 23.1 % of combined injuries. Independent sustentaculum fixation did not influence the rate of PTOA or re-operation (p = 0.92, p = 0.91, respectively).

Conclusion: Talar fractures have an associated sustentaculum fracture in approximately 6 % of cases, especially with Hawkins II fracture-dislocations. Over two-thirds of the associated sustentaculum fractures were missed on presenting radiographs, reiterating the need for heightened awareness and consideration of advanced imaging for all talus fractures. The rate of PTOA following these combined injuries at mean follow-up of 24 months does not exceed established rates after isolated talus fractures. Further research is required to determine the optimal management of the sustentaculum in these combined injuries.

Level of evidence: IV.