Outcomes Following Operative Management of Distal Humerus Nonunions

Objectives: To describe outcomes after distal humerus nonunion surgery and to identify risk factors for failure in the same population. METHODS: Design: Retrospective case series. Setting: Seven, academic, level I trauma centers. Patient selection criteria: Included were patients who underwent operative repair of a distal humerus (OTA/AO 13) nonunion and were ≥18 years old. Patients were excluded if they had clinical or serologic signs of infection prior to nonunion repair, or if their follow-up was less than 180 days and their surgery could not otherwise be classified as a success or failure. Outcome Measures and Comparisons: This study measured the rate of recalcitrant nonunion and complications following distal humerus nonunion surgery. It additionally evaluated associations between union rate and demographics, injury characteristics, and nonunion surgery characteristics. Results: Fifty-four patients with distal humerus nonunion were identified. Of the 30 included patients (mean age 47.5 (range 22-71), 18 (60%) male), 7 (23.3%) failed to unite after their index nonunion surgery at a study institution. Thirteen patients (43.3%) experienced one or more postoperative complications. While twenty-one of the 30 (70%) included patients initially sustained an open distal humerus fracture, all 7 patients (100%) who developed a recalcitrant nonunion initially sustained an open fracture. The use of bone graft or bone graft substitute relative to no graft, patient age, body mass index, smoking status, diabetes, and initial OTA/AO fracture classification were not associated with nonunion repair success rate (all p>0.05). Conclusion: This multicenter series challenged the concept that union rates are high, defined by the authors as >90%, following distal humerus nonunion surgery. Though limited by a small sample size that precluded multivariate regression, this study’s bivariate analysis suggests that an initially open distal humerus fracture may increase the risk of recalcitrant distal humerus nonunion. Modifiable risk factors were not associated with the success rate of nonunion surgery. These findings can be used to better inform patients’ expectations of results and complications following distal humerus nonunion surgery. Level of Evidence: Therapeutic level III