Surgical and methodologic aspects of proximal humeral osteotomy for stabilization of the shoulder joint.

It has previously been shown that a small retroversion angle might predispose to recurrent anterior shoulder dislocation, and in patients with remaining instability after soft-tissue repair the retroversion angle is often reduced. In these patients a rotation osteotomy of the proximal humerus to correct the anatomy in order to stabilize the joint can be advocated. The surgical technique for subcapital rotational osteotomy of the humerus is presented in this report. An isolated humerus has been osteotomized and radiographically examined in various positions. These findings, supplemented with mathematic calculations of the relationship between shift in millimeters of the osteotomy and angle of correction, have provided guidelines for obtaining accurate correction of the humeral head retroversion angle at surgery. The method has been used in seven patients with recurrent anterior shoulder dislocations, and all patients were operated on with a rotational osteotomy. Mean retroversion before surgery was 15°. It was changed after surgery to a mean value of 32°. All shoulders became stable and pain-free and had a normal range of motion. At the 3-year follow-up no radiologic signs of osteoarthrosis were found.