Page 48 - Hoag Orthopedic Institute 2018 Outcomes Report
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Surgeons at Hoag Orthopedic Institute were involved in the pre-market release FDA study
of the Reverse Shoulder Prosthesis (RSP)® and have performed the RSP procedure since it became available for use in the United States
in 2004. These specialists have contributed to the refinement of techniques, and have helped to explore novel uses for this implant design, particularly for patients in whom prior treatments have failed elsewhere (i.e., revision surgery).
In such situations, the absence of a functional rotator cuff leads to superior migration of the humeral head and the humeral head gradually erodes into the acromion and the glenoid, the shoulder joint portion of the scapula. The reverse
shoulder replacement is well-suited for such a scenario, as the glenosphere portion is fixed to the scapula using screws. In cases of severe bone loss, such as in long-standing arthritis or where prior surgery has compromised the existing bone stock, bone graft or a metallic augment can be used in place of the missing bone. Though bone loss on the humeral side is less common, this can be addressed using proximal humeral replacements or with an allograft-prosthetic composite. Recent advances in software provide the ability to template the surgery pre-operatively, which effectively allows the surgeon to virtually perform the surgery prior to implantation.
Figure 4. Pre-operative (left) and post-operative (right) radiographs of a patient without superior migration, but with severe rotator cuff disease and dysfunction along with complete loss of glenohumeral joint space and osteophytes (arthritis).
The reverse shoulder arthroplasty effectively compensates for the damaged rotator cuff by lengthening the arm and allowing the deltoid to compensate for the diseased rotator cuff.
    Figure 3. Post-operative AP radiograph of a left reverse shoulder arthroplasty with an augmented glenoid baseplate.

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