Functional outcome: Sixty-six patients were reviewed with a mean follow-up of 45 months. All implantations except one were performed to achieve pain relief. The absolute Constant score improved by 20 points (from 25 to 46) with a 7-point gain for pain (3 to 10), a 20° gain for active elevation, an 18° gain for external rotation, and a 0.4 point gain for force. Pain relief was greater with total prostheses. Only five patients stated they were dissatis-fied with the outcome despite the fact that 18 reported significant persistent pain. The Constant score was analysed as a function of follow-up, size of the humeral head, and preoperative morphology of the glenoid surface. Radiological outcome: Certain loosening was recognised for one glenoid and one humeral stem. Among 52 shoulders with strictly identical radiological results, 33 exhibited deterioration either for the vault or the glenoid or both, with no effect on the Constant score.
The differences between the hemi- and inverted arthroplasty groups concerned the Constant score, which was significantly better in the inverted prostheses (65.5) than in the hemiarthroplasties (46.1), for all subscores. Active elevation was 138° for the inverted prostheses and 97° for the Aequalis prostheses (p <
0.01). Mean external rotation in position 1 was 22° for the Aequalis prostheses and 11° for the inverted prostheses (p <
0.01) with no difference in elevation rotation. These results remained equivalent and significant over time, even beyond five years. Radiographically, there was one case with an anomalous humeral component (impaction) in the inverted group. For the inverted prostheses, there were three migrations that have not been revised to date and three partial screw loosenings. The main problem was the development of notches in the scapular column observed in 50% of the cases including 20% which reached the lower screw. For the Aequalis prostheses, the main problem was deterioration of the acromial vault observed in 50% of the cases leading to altered function.