Mitigating the Risk of Instability After Reverse Shoulder Arthroplasty: A Critical Analysis Review of Patient and Surgical Factors.

» Instability and dislocation after reverse shoulder arthroplasty may occur in up to 31% of patients. » Clinical risk factors for instability include younger age, male sex, increased body mass index, preoperative diagnosis of proximal humerus fracture or rotator cuff pathology, history of instability of the native shoulder or after surgery, and a medical history of Parkinson's disease. » Patients with rheumatoid arthritis and decreased proximity to the coracoid may also be at greater risk. » In patients at a high risk of instability, surgeons should consider a more lateralized prosthesis (particularly in patients with an incompetent rotator cuff), repairing the subscapularis (particularly when using a medialized prosthesis), and upsizing the glenosphere (>40 mm in male and 38-40 mm in female patients). » While potentially useful, less evidence exists for the use of a constrained liner (particularly with a lateralized glenosphere and/or in low-demand patients) and rotating the polyethylene liner posteriorly to avoid impingement.