Prevalence of axillary nerve lesions in patients undergoing proximal humeral fracture surgery using an anterolateral deltoid split approach assessed using EMG/ENG: a prospective trial

BACKGROUND: Proximal humerus fractures (PHFs) are the third most common type of fractures in adults with a lifetime risk of 13% for women aged 50 years and older and incidence increasing with age. While the burden of fractures is reportedly decreasing worldwide, an increase in fragility and osteoporotic fractures is expected. Treatment of these fractures differs between conservative treatment and surgical procedures such as closed reduction percutaneous pinning to open reduction internal fixation (ORIF), intramedullary nailing and arthroplasty, depending on patient factors and fracture severity. Indications for ORIF are displaced 2-part fractures as well as 3- and 4-part fractures in younger patients, with the deltopectoral approach and the deltoid split approach eliciting the best results. However, the anterolateral deltoid split approach is thought to lead to iatrogenic injury of the axillary nerve. Therefore, we aimed to investigate the extent of pre- and postoperative damage to the axillary nerve in proximal humeral fractures treated using an anterolateral deltoid split approach.METHODS: Electroneurography of the axillary nerve and electromyography of the deltoid muscle were performed pre- and postoperatively in patients with fresh proximal humeral fractures. Furthermore, the patients were clinically examined.RESULTS: Between March 2008 and April 2010, 19 patients with complex, but isolated proximal humeral fractures, who underwent osteosynthesis, were initially included in this prospective trial. Initial exclusion criteria were patients with polytrauma and abnormal skeletal development. Omission of postoperative follow-up examinations led to exclusion of two patients post-operatively. Preoperatively, 4/19 patients had a prolonged motor latency in the axillary nerve, indicating reduced nerve conduction velocity. Postoperatively, two additional patients had prolonged motor latency and decreased compound muscle action potentials of the axillary nerve. Follow-up at 12 months showed normal nerve conduction velocity and normal electromyography findings in all patients.CONCLUSIONS: Most of the axillary nerve lesions observed after surgery arose from the initial mechanism of injury, not the surgery itself. The choice of surgical approach did not seem to affect the rate of axillary nerve lesions in this study. Moreover, the deltoid split approach did not influence the function of the axillary nerve.