Reverse Radial Forearm Osteocutaneous Flap for Reconstruction of Thumb Metacarpal with Staged Interposition Arthroplasty for Treatment of Giant Cell Tumor: A Case Report.

A 28-year-old woman presented with a large lytic lesion and pathologic fracture of the right first metacarpal. Imaging demonstrated an expansile, destructive process with cortical breakthrough, and open biopsy confirmed the diagnosis of a giant cell tumor. Given the locally aggressive lesion and minimal remaining bone stock, the entire first metacarpal was excised. Definitive reconstruction was performed using a pedicled reverse radial forearm osteocutaneous flap, incorporating a vascularized segment of radius to recreate the thumb metacarpal. Same-stage metacarpophalangeal arthrodesis also was performed. Staged carpometacarpal (CMC) hardware removal and trapezial excision with ligament reconstruction and flexor carpi radialis tendon interposition were performed later to optimize thumb function and restore CMC motion while maintaining stability. At 16 months of follow-up, the patient demonstrated preserved thumb motion at the CMC and interphalangeal joints, successful flap healing, and no evidence of tumor recurrence.