Reverse total shoulder arthroplasty.

Reverse total shoulder arthroplasty designs have gained popularity over the last few years due to their satisfactory functional results in patients with cuff-tear arthropathy and other difficult reconstructive shoulder problems. These semiconstrained prostheses improve stability and active elevation in the absence of a functional rotator cuff by coupling a spherical glenoid component with a concave humeral component and increasing deltoid tension. Understanding the anatomy of the shoulder is critical in order to ensure secure fixation of the glenoid component, explore uncemented options for humeral component fixation, and determine the ideal soft-tissue tension to provide the best functional outcome without increasing the risk of complications. Key anatomic elements to be considered for the successful implantation of a reverse prosthesis include the orientation and size of the glenoid vault, the scapular regions with better bone stock (coracoid, spine of the scapula), the internal geometry of the humeral medullary canal, and the effects of reverse arthroplasty on the deltoid and brachial plexus. Copyright 2008 Wiley-Liss, Inc.