Documented Fracture-Healing Outcomes After Operative and Nonoperative Management of Closed Mid-Diaphyseal Humerus Fractures in Active-Duty Service Members.

INTRODUCTION: Closed diaphyseal humerus fracture treatment is nuanced with regard to the selection of surgical candidates. Fracture union is crucial, with historical data suggesting rivaling union rates between operative and nonoperative treatment; however, recent literature suggests increased union rates with operative treatment. Although nonoperative treatment of most fracture patterns is supported by the literature, there remains an argument for operative treatment for select patient populations, especially when considering union rates. Evidence regarding fracture-healing outcomes in young active-duty populations remains limited. We sought to characterize documented fracture-healing outcomes after operative and nonoperative management of closed diaphyseal humerus fractures in active-duty service members and to evaluate completeness of healing-status ascertainment.

METHODS: This study queried the Medical Assessment and Readiness System (MARS), Womack Army Medical Center, Fort Bragg, NC, which contains information from the Military Health System (MHS) care system. This study defined a retrospective cohort of patients diagnosed with closed diaphyseal humerus fractures (OTA/AO 12A/B/C), using International Classification of Diseases (9th and 10th revision) codes, sustained from January 2011 to December 2022. Treatment type, including operative or nonoperative, was identified. We excluded patients with open humerus fractures; proximal humerus fractures; distal humerus fractures; and those treated with external fixation. The primary outcome measure was a diagnosis of union or malunion/nonunion. Unadjusted comparisons between groups were conducted using likelihood ratio chi-square tests.

RESULTS: The study population comprised 402 patients with closed humeral diaphyseal fractures; 314 (78.1%) were managed nonoperatively and 88 (21.9%) operatively. Fracture-healing status could be classified in 216 patients (53.7%), whereas 186 (46.3%) lacked sufficient documentation to determine the primary outcome. Outcome ascertainment was more complete after operative than nonoperative management (61/88 [69.3%] vs. 155/314 [49.4%]; P = .001). Among those with documented healing status, union occurred in 149 of 155 nonoperatively managed fractures (96.1%; 95% CI, 91.8%-98.6%) and 59 of 61 operatively managed fractures (96.7%; 95% CI, 88.7%-99.6%).

DISCUSSION: Among active-duty service members with documented healing status after closed diaphyseal humerus fracture, observed union rates were high after both nonoperative and operative management. However, treatment was nonrandom, important fracture-specific treatment-selection variables were unavailable, and healing status was determined from available clinical documentation, recorded radiographic interpretations, diagnosis codes, and revision procedures rather than standardized radiographic adjudication. These limitations, together with incomplete and differential outcome ascertainment and few nonunion/malunion events, preclude estimation of a comparative treatment effect. The findings should therefore be interpreted descriptively rather than as evidence of equivalence between operative and nonoperative treatment.