Should the glenoid be replaced in shoulder arthroplasty with an unconstrained Dana or St. Georg prosthesis?

Twenty-six patients, 11 with rheumatoid arthritis and 15 with osteoarthritis, have been operated on with an unconstrained total shoulder arthroplasty. Mean follow-up was 47 months. Three prostheses have been extracted. All patients stated that they had pain relief after surgery. At three year follow-up all except one had developed radiolucent zones around the glenoid component. No zones were observed around the humeral component. In shoulders with preserved glenoid surface replacement of only the humeral head might provide better long-term results than a total shoulder arthroplasty.