Periprosthetic Humeral Fractures
Published: April 29, 2024
Periprosthetic humeral fractures are uncommon, and can occur either intraoperatively or postoperatively. Risk factors for intraoperative humeral fractures include those that increase mechanical stress on the bone or decrease bone quality. A study of periprosthetic fractures during revision reverse shoulder arthroplasty showed that most occurred during implant removal.[1] As the humerus is weakest to torsional stress, minimizing humeral torsion through appropriate soft-tissue releases and meticulous surgical technique helps to decrease the risk of intraoperative fracture. Postoperative humeral fractures most often occur as a result of trauma or humeral osteolysis. Increased medical comorbidity is correlated with an increased risk of postoperative humeral shaft fractures.[2] Although classification and treatment of periprosthetic humeral fractures are controversial, certain principles apply. Treatment depends on fracture location, prosthesis type and stability, rotator cuff status, patient comorbidity, and bone quality.[3] Decision-making is guided by the goal of obtaining a stable, well-functioning humeral component. Intraoperative fractures that do not compromise component stability or function may be treated with fixation or benign neglect.[4] However, component exchange is necessary if the fracture does cause such compromise despite fixation. When a patient presents with a postoperative humeral fracture, it is essential to determine stem stability. Although nonoperative treatment is an option when the stem is stable, the success rate is low, whereas operative treatment is associated with a high union rate.[5] The specific surgical technique varies depending on component stability, bone quality, and fracture location. In general, open reduction and internal fixation is an option for fractures involving a stable humeral component and good bone stock. Other options include revision to reverse shoulder arthroplasty for tuberosity fractures, and revision to a long-stem component for humeral shaft fractures. Augmentation with cortical allograft struts is available if bone quality is poor. Unstable humeral stems should be revised. In the setting of severe proximal bone loss, techniques for management include endoprosthetic or allograft-prosthetic reconstruction. Management of periprosthetic humeral fractures is complex, and can have a high complication rate.[6] The optimal treatment strategy remains unknown. Decision-making depends on both patient-specific and fracture-specific factors. Increasing use of short-stem and stemless humeral component designs will alter the type of periprosthetic factors encountered. 