Avoiding and managing the unstable shoulder arthroplasty

Abstract

Instability is one of the most common complications following shoulder arthroplasty. Restoration of soft tissue balance is the key to avoiding instability and in managing instability after prosthetic replacement. Certain pathological conditions associated with glenohumeral degeneration are typically associated with fixed or dynamic subluxation or dislocation in an inferior, superior, anterior, or posterior direction. Joint capsule, rotator cuff components, and deltoid may be deficient, attenuated, or overly tight. Bone stock and the coracoacromial arch may be deficient. There may be a nerve injury. In addition, the components may be malpositioned, loose, or worn. Tuberosity malposition may exist especially after treatment of proximal humeral fractures. Excision, release, plication, repositioning, or augmentation of the pathological structures or revision of the components may be needed to restore soft tissue balance, stability, motion, and longevity of the arthroplasty. Overcorrection may result in instability in another direction. Rarely resection reverse arthroplasty, or arthrodesis may be warranted in the unsalvageable situation. Restoration of stability at the index arthroplasty procedure should be the surgeon's goal to avoid the need for secondary salvage.