Primary vs Secondary Subtalar Arthrodesis After Calcaneus Fracture: A Propensity Score–Matched Analysis
Arsh N. Patel, Manuela Gaviria, Pratham Patel, Zachary T. Roward, Jeannie HuhBackground:
Subtalar arthrodesis (STA) may be used to treat displaced intra-articular calcaneus fractures (DIACFs), either acutely as primary treatment, or secondarily for post-traumatic arthritis after open reduction and internal fixation (ORIF) or nonoperative management. However, it remains unclear whether a prior calcaneus fracture affects union after subsequent STA. The purpose of this study was to compare nonunion and repeat/revision STA rates following primary STA with delayed secondary STA after either initial calcaneal fracture ORIF or nonoperative fracture management.
Methods:
A retrospective cohort study was performed using the TriNetX Research Network. Adult patients undergoing STA between January 1, 2000, and December 31, 2023, were categorized into 3 groups: primary STA performed within 6 weeks of calcaneus fracture diagnosis (Primary STA); secondary STA following calcaneal ORIF (ORIF-Secondary STA); and secondary STA following initial nonoperative fracture management (Nonoperative-Secondary STA). Patients were required to have a documented health care visit between 3 months and 2 years following index STA. Three separate 1:1 propensity score–matched comparisons were performed using age, sex, BMI, tobacco use, diabetes mellitus, chronic kidney disease, peripheral vascular disease, and osteoporosis. The primary outcome was nonunion within 2 years of STA. Repeat STA within 2 years was evaluated as a secondary outcome and used as a claims-based surrogate for revision STA.
Results:
After propensity score matching, Primary STA vs ORIF-Secondary STA included 201 patients per cohort. Primary STA showed significantly lower rates of both nonunion (13.4% vs 21.9%; risk ratio [RR] 0.614, 95% CI 0.396-0.950;
Conclusion:
Primary STA was associated with lower 2-year nonunion rates compared with delayed secondary STA following either initial ORIF or nonoperative calcaneus fracture management. Among patients undergoing delayed STA, no significant difference could be detected with the numbers available for nonunion based on initial fracture management; however, repeat/revision STA was significantly more frequent following prior ORIF compared with nonoperative management. These findings suggest that surgical timing and prior fracture management may influence outcomes following STA in the setting of calcaneus fracture.
Level of Evidence:
Level III, retrospective cohort study.