While traditional total shoulder replacement (TSA) is an excellent treatment choice for most people with severe shoulder arthritis, in some patients with a deficient rotator cuff TSA has a very high rate of failure. Recently reverse shoulder replacement (RSA) has been developed to address this problem. In an RSA, the shoulder socket (glenoid) is actually replaced by a hemi-spherical ball and the original ball (humeral head) is replaced by a socket (hence the term 'reverse'). RSA has been very successful in alleviating pain and restoring function in this group of patients. Dr. Gramse is one of the few surgeons in Southern Maine to have training and experience with this complex procedure.