Scaphotrapeziotrapezoid Fusion for Chemotherapy-induced Capitate Avascular Necrosis.

The capitate's retrograde vascular supply and limited intraosseous anastomoses predispose its proximal pole to avascular necrosis, although this remains rare. Although typically linked to trauma, connective tissue disorders, or corticosteroid use, avascular necrosis may also arise secondary to chemotherapy. We present the case of an 18-year-old woman with a history of childhood leukemia who developed capitate avascular necrosis. This case emphasizes the importance of considering avascular necrosis in chemotherapy-exposed patients presenting with atraumatic wrist pain and evaluates outcomes of scaphotrapeziotrapezoid (STT) fusion, an approach that stabilizes the carpus and unloads the capitate. After achieving acute lymphoblastic leukemia remission at age 11, the patient developed multifocal avascular necrosis involving both knees, the femurs, and the right wrist, which were treated conservatively. At 18, she presented with persistent wrist pain requiring surgical intervention. Intraoperatively, the proximal capitate pole was nonunited, with autofusion of the trapezium and trapezoid. Two 0.045 K-wires were placed through the trapezium toward the scaphoid and scaphotrapezoidal space. A spacer preserved joint height, and cancellous bone graft from the distal radius filled the intercarpal space. The wrist was fixed in 45-degree extension and maximal radial deviation. A radial styloidectomy and posterior interosseous neurectomy were performed. At the 10-week and 6-month follow-up, the patient was pain-free with preserved wrist motion, consistent with the progressive STT fusion seen on radiographs. Capitate avascular necrosis is a rare clinical entity. This case highlights STT fusion as a reliable treatment option for preserving wrist mobility and function while minimizing pain.