Conservative Treatment Achieving Bone Union in a Displaced Wright and Cofield Type B Periprosthetic Humeral Fracture After Reverse Shoulder Arthroplasty: A Case Report.

Periprosthetic humeral fracture is a serious complication after reverse shoulder arthroplasty (RSA). Wright and Cofield classification type B fractures occur around the tip of the humeral stem. In these fractures, the intramedullary canal is occupied by the stem and cement, which reduces endosteal blood supply and makes fracture healing more difficult. As a result, surgical management, such as open reduction and internal fixation or revision arthroplasty, is commonly recommended when displacement is present. However, these procedures are highly invasive and may pose substantial perioperative risk in elderly patients.  An 82-year-old woman with multiple comorbidities underwent bony increased offset RSA (BIO-RSA) using a cemented humeral stem (Aequalis Ascend Flex; Stryker, Kalamazoo, USA). At postoperative year 4, she fell, which resulted in a displaced Wright and Cofield type B periprosthetic humeral fracture (type B fracture). Although valgus angulation progressed to 20° and the stem tip migrated medially, she had minimal pain and preferred nonoperative management due to her high surgical risk. Radiographs demonstrated preservation of cortical integrity on the lateral, anterior, and posterior aspects. Progressive callus formation was observed, and at one year after injury, bridging callus confirmed bone union. Forward elevation reached 100°, and she remained pain-free in her daily activities.  Despite concerns that type B fractures are at risk for impaired union due to loss of endosteal blood supply, this case achieved bone union with conservative treatment. Preserved cortical continuity on three cortices likely maintained periosteal blood flow, which may have compensated for compromised intramedullary circulation. These findings suggest that nonoperative treatment may be feasible in selected patients, particularly when cortical integrity is preserved. Conservative treatment can achieve bone union even in displaced Wright and Cofield type B periprosthetic humeral fractures after RSA. Careful evaluation of cortical continuity on orthogonal radiographs, together with patient factors such as age and comorbidities, is essential when determining the optimal management strategy.