Mini-Open Sinus Tarsi Approach with Percutaneous Screw Fixation of Displaced Calcaneal Fractures: A Prospective Computed Tomography-Based Study

Background: Open reduction and internal fixation (ORIF) of calcaneal fractures using an extended lateral approach results in soft tissue disruption and theoretically subtalar joint stiffness. A minimally invasive sinus tarsi approach for posterior facet exposure and percutaneous screw fixation of the calcaneal body has been implemented. This report details the reduction and stability of the internal fixation resulting from this approach. Methods: Twenty-one consecutive patients (18 male, 3 female, 45 +/- 16 years) with 22 calcaneal fractures underwent ORIF with minimal exposure through the sinus tarsi for reduction, lateral plate fixation, and percutaneous screw fixation. There were nine Sanders type II fractures and 13 type III fractures. Sixteen fractures had calcaneocuboid joint involvement. Nineteen patients (19 fractures) were available for follow-up (mean, 32 +/- 14 months). Two computed tomography scans were obtained on each patient, one immediately postoperatively and one after a minimum of 1 year, to evaluate reduction and fixation stability, respectively. The posterior facet and calcaneocuboid joint were graded excellent, good, fair, or poor, according to articular step, defect, and angulation. Any change was considered loss of stability. Similarly, on a conventional two-dimensional radiograph, more than 5 of Bohler's angle difference was defined as loss of calcaneal height. Results: Postoperative posterior facet and calcaneocuboid joint reduction was good (step < 1 mm, defect < 5 mm, angulation < 5 degrees) or excellent (no step, defect, angulation) in 14/22 (64%) and 11/16 fractures, respectively. At follow-up, no loss of reduction at the posterior facet and calcaneocuboid joint was noted. More than 5 of Bohler's angle decrease was found in three patients. Conclusion: Even complex calcaneal fractures can be sufficiently exposed by a minimally invasive sinus tarsi approach for anatomic reduction and stable fixation. Most patients had good or excellent functional results, which may have resulted from minimal soft tissue disruption.