Surface Replacement Arthroplasty of the Shoulder
Over the past ten years the design of the surface replacement prosthesis has evolved, but the basic concept and design of surface replacement, minimal removal of bone and cementless fixation has remained constant. The indications and surgical technique has been refined during this period. The results of hemiarthroplasty are not to be compared with those of total shoulder replacement. The indications are different. The early results of the Hydroxyapatite coated prosthesis are extremely encouraging with no lucent lines observed.
The surface replacement prosthesis has demonstrated results equal to those of conventional stemmed prostheses suggesting that the humeral component does not need a stem or cement for fixation.
Since stemmed prostheses are subject to inherent complications, the indications for specific types of replacement are changing. The question now is not: what are the indications for surface replacement, but what are the indications for stemmed prostheses?
In our view the only indications for the use of a stemmed prosthesis are in acute four-part fractures and in those patients with severe destruction of the humeral head such that no surface remains to be replaced.