Future Directions in Total Shoulder Arthroplasty

Reverse shoulder prosthesis system components. The metal screw-fixed ball is implanted in the scapula to replace the glenoid, and the concave polyethylene component mounted on the stem is implanted into the proximal humerus to replace the humeral head (image courtesy of Encore Medical, Austin, TX). 

Constrained versions of this concept have been used earlier and were largely unsuccessful because of loosening (Boulahia et al. 2002). In 1987, Grammont and Baulot designed a semiconstrained reverse prosthesis and recommended it be used prudently and in patients older than 70 years of age (Boulahia et al. 2002). Since then, reports from Europe have noted its success in a limited number of rotator cuff deficient patients after relatively short (2 to 3 years) follow-up periods (Boulahia et al. 2002, De Wilde et al. 2001, Rittmeister and Kerschbaumer 2001). 

In general, the success rate of TSR exceeds 90% for a wide range of common shoulder problems. As in THA and TKA, the aim of TSA is to reduce pain, restore damaged anatomy, and restore function. As for hip and knee arthroplasty, there are continuing concerns about component fixation and persisting instability of the joint. 

In spite of these issues, TSA witii UHMWPE remains a successful procedure bringing lasting pain relief and restoration of function to tens of thousands of patients worldwide every year. 

Anglin C., U.P. Wyss, and D.R. Pichora. 2000. Glenohumeral contact forces. Proc Inst Mech Eng [H] 214 637-644. 

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