This study from the Mayo Clinics (Arizona and Minnesota clinics) showed encouraging results for patients with severe shoulder destruction and rotator cuff tears. They successfully replaced the shoulder joints of 19 patients with a reverse shoulder replacement. Early results (after three years) were good but there were some complications.
The mechanics and design of the reverse shoulder replacement are the exact opposite of a traditional shoulder replacement. In the reverse implant, the ball portion of the shoulder is placed where the socket use to be and the socket is where the ball or humeral head occurs naturally in the normal shoulder joint. This new design has made it possible to create a much more stable shoulder joint that can function without a rotator cuff.
The loss of the support and function of the rotator cuff muscle is the key ingredient here. Without this important muscle group, patients with severe rheumatoid arthritis do not do well with the traditional shoulder replacement. But concerns about bone loss and a lack of information on how patients with rheumatoid arthritis would do with this type of implant have kept surgeons from using the reverse shoulder replacement.
That’s why this study is so important. For the first time, we have some early results that support this type of treatment for patients with rheumatoid arthritis affecting the shoulder(s). The 19 patients included men and women between the ages of 58 and 81. Some of the patients (a total of five of the 19) had previous surgery (rotator cuff repairs) that failed.
Results of the reverse procedure were measured using pain levels, shoulder motion, and function of the arm that depended on use of the shoulder. X-rays were used to show position and condition of the implant. X-rays also show the degree of scapular notching.
A notch (opening) in the scapula (shoulder blade) is where an important nerve (the subscapular nerve) passes through. The natural size, shape, and location in the bone can vary. If the ligament across the top of this notch is tight and pressing down on the nerve and/or if the notch is too shallow or too small, the surgeon must make corrections in order to take pressure off the nerve.
Compared with preoperative measurements, the postoperative results were excellent for 12 of the 19 patients. Five others had satisfactory results. Only two had an unsatisfactory outcome. There were a few complications but most were not directly related to the surgery. Falls leading to bone fractures were the biggest postoperative problem but these were not directly related to (or caused by) the shoulder replacement surgery. No one in the study needed revision surgery.
In conclusion, patients with severe shoulder joint destruction from rheumatoid (inflammatory) arthritis are not without some options. According to the early results of this Mayo clinic study, the use of reverse shoulder arthroplasty can benefit these patients. The main indication for the use of reverse shoulder replacements has always been severe rotator cuff damage. It looks like a reverse prosthesis can also successfully reduce pain and significantly improve function previously affected by limited motion. The authors say they will continue using this procedure with their patients when appropriate.