Nonunion developed in 10.4% of proximal humeral fractures after nonoperative treatment
Published results showed a higher prevalence of nonunion after nonoperative treatment of proximal humeral fractures than previous research, with a greater risk among patients with substantial head-shaft angle and translation and who smoke.
Using standard clinical evaluation and conventional radiographs, researchers assessed fracture union in 2,230 patients who underwent nonoperative treatment for proximal humeral fractures. Researchers also assessed the prevalence of nonunion and measured the effect of 19 parameters on healing. Researchers used best statistical practices to construct a multivariate logistic regression model and externally validated the proximal humeral fracture assessment of risk of nonunion model in a subsequent prospectively collected population of 735 patients.
Results showed 10.4% of patients developed nonunion, with nonunion found in 0.8% of 395 patients with a head-shaft angle greater than 140° and in 12.4% of 1,835 patients with a head-shaft angle of 140° or less. Multivariate logistic regression analysis showed none of the measured candidate variables were independently predictive of nonunion among patients with a head-shaft angle of greater than 140°. However, researchers found decreased head-shaft angle, increasing head-shaft translation and smoking were independently predictive of nonunion on multivariate analysis for patients with a head-shaft angle of 140° or less. Most patients with both a head-shaft angle of greater than 90° and head-shaft translation of less than 50% had a low prevalence of nonunion, according to results. Researchers noted an 83.7% risk of nonunion in the 8.3% of patients with a head-shaft angle of 90° or less and head-shaft translation of 50% or greater. Results showed a higher prevalence of nonunion among patients who smoked in both groups.
“Surgery aimed solely at preventing nonunion exposes patients to the risk of other complications that are not encountered with nonoperative treatment. However, we believe that medically fit patients with translated and/or angulated fractures should be counseled about smoking cessation and considered for surgery to avoid the debilitating effects of subsequent nonunion,” the authors wrote. “Nonunion risk is only one of many considerations in counseling patients with regard to treatment options. However, we hope that our study increases the overall awareness of the substantial risk of nonunion that exists after nonoperative treatment in certain patients, while enabling more precise quantification of this risk than previously has been possible.”