Constrained total shoulder joint replacement: a critical review.
Constrained total shoulder replacement is a salvage procedure for the patient with disabling pain and a nonfunctioning rotator cuff mechanism. The results of pain relief have been gratifying. When active overhead motion is a goal of treatment a strong deltoid muscle is required. The rationale for fixing a fulcrum is to substitute for the loss of the rotator cuff mechanism that stabilizes the humeral or prosthetic head on the shallow glenoid. The best method of attachment for the glenoid component to an intact glenoid vault described herein has been found to be superior to other methods. In particular, the vault should not be mutilated. This is borne out by the clinical experience and laboratory testing that loosening or pull-out does not occur with an intact glenoid. Moreover, the attachment is stronger than the dry bone just medial to the vault where fracture always occurred through the suprascapular notch in laboratory tests. Although there may be good pain relief with this operation, active function still depends on residual deltoid muscle power wherein a poor deltoid will only allow passive motion. Moreover, the outcome of any shoulder operation still depends in large measure on the excellence of the postoperative rehabilitation program. Finally, other worthwhile shoulder operations should be given first consideration in order to serve the needs of individual patients.