The treatment of subcapital humerus fracture with dynamic helix wire and the risk of concommitant lesion of the axillary nerve.

Displaced subcapital fractures of the humerus represent a therapeutic challenge for the surgeon, all the more so because of their high incidence among osteoporotic patients. Open surgical repair involves increased risk of avascular necrosis of the humeral head, while percutaneous reduction and fixation often fails as a result of loosening pins. As a possible solution, a minimally invasive technique was developed in which a dynamic titanium wire helix is inserted into the medullary space of the diaphysis of the humerus and then rotated proximally into the head fragment. This new approach for osteosynthesis was performed in 84 patients, most of whom had suffered two- or three-part fractures. Results were evaluated by the Constant Functional Score, indicating an average 87% rehabilitation. An associated anatomical study of 53 human cadavers investigated the position of the main branches of the axillary nerve relative to the surgical placement of the wire helix. In all cases, the distance between the most vulnerable anterior branch of the axillary nerve (ABAN) and the operative site was sufficient, as long as insertion occurs in the distal third of the distance between the head of the humerus and the deltoid tuberosity. Utilization of the titanium helix results in prompt healing of subcapital fractures while offering minimal risk for the elderly osteoporotic patient and does not endanger branches of the axillary nerve.