Successful treatment of fractures of the base of the acromion after reverse shoulder arthroplasty: Case report and review of the literature.

Fractures of the acromion and scapula are known to occur after reverse shoulder arthroplasty. We present a case of a fracture at the base of the acromion 5 months after arthroplasty treated successfully with dual plating of the acromion. Eighteen months after fracture fixation, the patient had 160 degrees of active forward flexion, a QuickDASH of 29.5, a Constant score of 69 and she was satisfied with the result. A concomitant review of the literature produced, in addition to our patient, 56 cases. These were used to produce a classification system, based on bony and functional anatomy as follows. Tip fractures are of the most lateral or anterior portion of the acromion, those of the body of the acromion are medial to the tip but lateral to the beginning of the scapular base. Fractures at the scapular base are termed fractures of the base of the acromion and those more medial to that, fractures of the scapular spine. The functional results of these case series demonstrated poorer functional outcomes for more medial fractures. As future research in this domain increases, clarity on the nomenclature of these fractures will allow for prognostication and treatment based on fracture location as well as comparison between studies.