Figure 1. Anteroposterior radiograph of the right shoulder.
Figure 2. Coronal MRI image of right shoulder.
Figure 3. Sagittal MRI image.
A 62-year-old man presents with a complaint of right shoulder pain that has been present for several months. The pain is made worse with reaching over head and he feels the shoulder is now weak. He has failed 2 courses of formal physical therapy and received cortisone injections with minimal short-term improvement. On examination, the patient has a positive drop arm and weakness with forward flexion in the scapular plane (Figures 1-3).
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The patient presents with right shoulder arthritis and a large, retracted rotator cuff tear. The radiograph of the shoulder shows a decreased acromiohumeral interval indicating superior migration of the humeral head. The coronal magnetic resonance imaging (MRI) shows fatty atrophy of the supraspinatus muscle indicating the rotator cuff is irreparable. Superior migration of the humeral head, glenohumeral arthritis, and an irreparable rotator cuff describe a condition called rotator cuff arthropathy, which is an indication for a reverse total shoulder arthroplasty.1,2
A traditional total shoulder arthroplasty requires an intact rotator cuff to function properly. A reverse prosthesis moves the center of rotation inferiorly and medially, which allows the deltoid to provide forward flexion of the shoulder. The benefit of a reverse total shoulder arthroplasty is primary pain relief, and to a lesser extent, improved shoulder abduction, as the deltoid replaces the function of a deficient rotator cuff.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.
1. Familiari F, Rojas J, Doral MN, Huri G, McFarland EG. Reverse total shoulder arthroplasty. EFORT Open Rev. 2018;3(2):58-69. doi:10.1302/2058-5241.3.170044
2. Gerber C, Pennington SD, Nyffeler RW. Reverse total shoulder arthroplasty. J Am Acad Orthop Surg. 2009;17(5):284-295. doi:10.5435/00124635-200905000-00003