Factors associated with nonunion of the posttraumatic subtalar arthrodesis after displaced intra-articular calcaneal fractures.

Background: This study investigated the incidence of and risk factors for nonunion in patients with posttraumatic subtalar arthrodesis (SA).

Methods: We retrospectively reviewed 165 posttraumatic SA cases. Nonunion was diagnosed at 6 months after surgery based on the findings of clinical evaluations, plain radiographs, and CT scans. Patient-specific factors and surgeon-specific factors were evaluated as potential risk factors.

Results: The overall nonunion rate was 13.3 % (22 of 165 cases). In the final multivariate logistic regression analysis, smoking (odds ratio [OR] = 3.64; 95 % confidence interval [CI] = 1.23-10.75), parallel screw configuration (OR = 5.70; 95 % CI = 1.62-20.06), and freeze dried iliac crest (OR = 9.16; 95 % CI = 2.28-36.79) were demonstrated as risk factors for nonunion of posttraumatic SA.

Conclusion: Patients with a history of smoking, parallel screw configuration fixation, and those who received freeze dried iliac crest as an interpositional graft, had a significantly higher rate of nonunion.