Humeral Metadiaphyseal Fracture With Severe Osteoarthritis of the Shoulder and Simultaneous Contralateral Proximal Humeral Fracture Treated With Bilateral Reverse Shoulder Arthroplasty: A Rare Case Report.

Simultaneous bilateral proximal humerus fractures (PHFs) are infrequent. Particularly rare are cases of PHFs extending to the metadiaphysis accompanied by severe osteoarthritis (OA) of the shoulder. To our knowledge, there have been no reports of bilateral fractures that include metadiaphyseal fractures with severe OA on one side and a PHF on the contralateral side, treated with bilateral reverse shoulder arthroplasty (RSA). We present a case of an 84-year-old woman with a right humeral metadiaphyseal fracture with severe OA and a left proximal humeral fracture, both treated with bilateral RSA. The surgical technique for the humerus metadiaphyseal fracture involved adjusting soft-tissue tension for RSA, where the proximal bone fragment was opened and wrapped around the humeral component. The clinical outcomes of this case suggest that this surgical technique can be a viable option to restore function in rare cases of humeral metadiaphyseal fractures with severe OA of the shoulder and simultaneous contralateral proximal humeral fractures.