[Fractures of the humeral head]

Abstract

Fractures of the humeral head are very common in elderly people, with 70% of all such fractures being seen at an age of more than 60 years. For the radiological examination of the fracture, x-rays from two levels are mandatory. The number and position of the fragments, assessment of intact or ruptured periosteum between the fragments and muscle forces acting on the fragments have to be determined from the x-rays. A 3-D CT scan can be very useful for better understanding of the character of the fracture. The remaining displacement between fragments after reduction have to be evaluated according to their location. Even small incongruities between fragments in the subacromial space will impair the gliding mechanism, whereas remaining displacements between the head and shaft can be accepted to a much larger extent. According to the fracture mechanism, we can basically differentiate between avulsion fractures and depression fractures. The avulsion fractures are characterised by a varus tendency of the humeral head,whereas the depression fractures are characterised by a valgus position of the head fragment. This has to be taken into consideration when choosing the implant for fixation. The indication for reconstructive surgery or prosthetic replacement depends on the type of fracture, on the quality of bone and on the familiarity of the surgeon with the treatment of humeral head fractures. The implants currently used for fixation can basically be differentiated between rigid and semi-rigid. The indication for the one or the other depends on the fracture type and the bone quality. In general, for simple fractures and in case of poor bone quality semi-rigid implants are indicated. Despite the fact that an understanding of the character of the fractures and implants has improved over the last few years, there are still types of fractures which need primary prosthetic replacement.