Predictors of nonunion after nonoperative treatment of displaced midshaft clavicle fractures.

Abstract

Nonunion is a significant complication following nonoperative treatment of displaced midshaft clavicle fractures, potentially leading to impaired shoulder function, pain, and decreased quality of life. This study aims to identify predictors of nonunion in adults treated nonoperatively to optimize treatment decisions and improve outcomes. A retrospective cohort study was conducted using data from 374 patients treated nonoperatively between 2012 and 2024. Patient and fracture characteristics, including age, sex, smoking, diabetes mellitus, and fracture comminution, were assessed. Univariable and multivariable logistic regression analyses identified predictors of nonunion. Model performance was assessed using the area under the receiver operating characteristic (ROC) curve (AUC). Diagnostic statistics and number needed to screen (NNS) were calculated. Of 374 patients, 72 (19.3 %) developed nonunion. Multivariable analyses revealed that increasing age (odds ratio [OR]: 1.03, 95 % confidence interval [CI]: 1.01-1.04, p = 0.002) and smoking (OR: 2.49, 95 % CI: 1.31-4.71, p = 0.005) were independently associated with increased risk of nonunion. Fracture comminution was associated with reduced risk (OR: 0.34, 95 % CI: 0.20-0.58), p < 0.001). The model's AUC was 0.70. At a probability threshold of 0.4, the NNS was 6. This study highlights the potential of predictive models to identify patients at risk for nonunion. Age and smoking increase the risk of nonunion, while comminution showed a protective effect. These findings support personalized care to optimize treatment decisions and improve patient outcomes. Further refinement and inclusion of additional risk factors are essential to improve the model's accuracy and clinical applicability.