Long-term results of cemented metal-backed glenoid components for osteoarthritis of the shoulder.

BACKGROUND: There has been recent renewed interest in the use of metal-backed glenoid components in total shoulder arthroplasty. However, little information is available on the long-term results. The purpose of this study was to determine the results, the risk factors for an unsatisfactory outcome, and the failure rates of total shoulder arthroplasty with a cemented metal-backed glenoid component.

METHODS: Between 1985 and 1991, 100 total shoulder arthroplasties with Neer cemented metal-backed glenoid components were performed at our institution to treat osteoarthritis. Ninety-five shoulders were followed for a minimum of two years (mean, 10.8 years) or until the time of revision surgery. Patients were assessed with use of a modified Neer rating system at the time of the latest follow-up. Radiographs of eighty-three shoulders were assessed for the presence of glenoid erosion, glenohumeral subluxation, periprosthetic lucency, and a shift in component position.

RESULTS: Total shoulder arthroplasty with a cemented metal-backed glenoid component was significantly associated with pain relief (p < 0.001) as well as with an improvement in abduction from a mean of 92 degrees to 146 degrees (p < 0.001) and external rotation from a mean of 26 degrees to 60 degrees (p < 0.001). According to the modified Neer result-rating system, the result was excellent in forty-seven shoulders, satisfactory in twenty-seven shoulders, and unsatisfactory in twenty-one shoulders. Five patients underwent revision surgery because of component loosening (two patients), component subluxation (one patient), a fracture distal to the stem (one patient), and polyethylene wear (one patient). Glenoid periprosthetic lucency was present in sixty-nine (83%) of eighty-three shoulders at a minimum radiographic follow-up of two years.

CONCLUSIONS: The data from this study suggest that total shoulder arthroplasty with a cemented metal-backed glenoid component for the treatment of osteoarthritis is associated with pain relief and improvement in motion. However, the high rate of glenoid periprosthetic lucency is concerning and requires additional follow-up and investigation. These results are not better than those that have been reported for all-polyethylene cemented glenoid components.