Total Shoulder Replacement: Long-Term Results

Abstract

The development of total shoulder replacement in the United States has paralleled that of other joints. Prior to the 1950s, surgery on the shoulder for painful arthritic states was limited to arthrodesis or resection arthroplasty. Debridement was only temporarily and marginally beneficial, and the functional results of arthrodesis or resection left much to be desired. In the early 1950s Dr. Neer began to use a metal humoral prosthesis - a hemiarthroplasty - for certain fractures and milder forms of arthritic degeneration. This prosthesis has proven to be quite durable and effective for these indications, but is was recognized that there were certain conditions with extensive glenoid involvement or bone loss that could not be adequately managed with such a device. A constrained device was an appealing alternative because of the theoretical advantage of providing the stability needed in such instances, and early investigative work was done in this area. The conclusions reached in this early research indicated that a constrained device was not adequately powered when the rotator cuff was sacrified. The loss of function of the infraspinatus and the teres minor as external rotators led to poor functional levels. Conversely, when the muscle power was preserved, fixation of the prosthesis became a problem, or the components would fail. This sequence of events has been experienced by others working in the area of constrained joint replacement. It was concluded that a constrained device invited mechanical failure or was powered inadequately by the deltoid alone, and that such a device was inappropriate in young or active patients and in patients with weak bone.