Mitigating Fracture of the Acromion and Scapular Spine After Reverse Shoulder Arthroplasty

Abstract

» Biomechanical studies report that thin scapular spine (SS) morphology, superiorly placed glenoid components, and increased glenoid baseplate screws contribute to increased acromial and SS strain and may increase fracture risk. » Clinical risk factors of acromial and SS fractures after reverse shoulder arthroplasty include increasing age, female sex, osteoporosis, rheumatoid arthritis, thin midsubstance acromion morphology, previous acromioplasty, and surgical indication of cuff tear arthropathy. » Clinical studies show that, in isolation, excessive humeral lengthening, humeral lateralization, and glenoid medialization may increase risk of acromial and SS fractures. » Biomechanical studies suggest that a combination of glenoid medialization and humeral lateralization (MG/LH) may reduce fracture risk, although this requires clinical correlation. » Surgeons might reduce fracture risk in patients of high-risk groups by guarding against excessively lengthening the humerus, using a MG/LH prosthesis, and targeting screws to avoid the scapular notch and base of the SS. Level of Evidence: Level V. Narrative Review. See Instructions for Authors for a complete description of levels of evidence.