Acute anterior shoulder dislocation is the most common joint dislocation in orthopedic emergency , accounting for approximately 45% of all acute joint dislocations. The primarysenile anterior shoulder dislocation accounts for approximately 20%-40% of the anterior shoulder dislocation, and the elderly women of over 70 years old are the predisposed population. The traumatic mechanism and comorbidity of senile anterior shoulder dislocation are different from those of younger occurrence , and the incidence and severity of anterior shoulder dislocation combined with proximal humeral fractureincrease with age. However, in addition to greater tuberosity fracture, the majority of concomitant humeral neck fractureis not obviously displaced.If the humeral neck fracture is missed, severe complications such as the complete separation ofhumeral head andshaft may occur during reduction.Currently, the number of senile anterior shoulder dislocation is on rise, and there are frequent reports of such complication in elderly patient.The blood supply of humeral head is severely damaged after the complication.The necrosis rate of humeral head is high after open reduction and internal fixation. Although shoulder arthroplasty is indicated for this population of elderly patient, it is expensive and difficult to achieve good result. The occurrence of such complications during the reduction process is an urgent problem to be solved. Objective To analyze the possible reasons of iatrogenic humeral neck fracture in the process of closed reduction of senile anterior shoulder dislocation and explore the methods of avoidance.

From 2012 to 2017, the clinical data and imaging characteristics of patient with humerus neck fracture during the reduction of anterior shoulder dislocationin our hospital were retrospectively analyzed.

A total of 5 patients suffered from humerus neck fracture during closed reduction, and the separation of humeral head and neck was resulted. The characteristics of these patientsincluded elderly women, low energy injuryand primary shoulder dislocation.The anteroposterior view of shoulder joint before reduction revealed anterior shoulder dislocation with greater tuberosity fracture and the moving inward of humeral head to the inferior or medial of coracoid process. All the reductions were performed without anesthesia using Hippocrates method.

The cause of humeral neck fracture in the reduction process ofanterior shoulder dislocationisrelated to the humeral neck fractureaccompanied during the missed glenohumeral joint dislocation.The senile anterior shoulder dislocation has its own characteristics and should be distinguished from younger occurrence in the treatment.Special attention should be paid to primary senile anterior shoulder dislocation with greater tuberosity, and the exclusion of humeral neck fracture by standard imaging examination is the key to avoid such iatrogenic complications.