INTRODUCTION Arthrodesis of the shoulder is a straightforward and established alternative to reconstruct the shoulder function after tumor resection of the proximal humerus. In most cases, some kind of intercalary bone graft is used to bridge the bony defect. However, due to low stability of a single fibula autograft and disadvantages of exogenous graft material when performing combined allo- and autograft reconstruction, efforts to develop new surgical techniques, with the intention to lower the complication rates, are ongoing. MATERIALS AND METHODS We present a detailed description of the surgical technique and the outcome of three patients with osteosarcomas of the proximal humerus, which were treated with tumor resection and autologous double-barrel vascularized fibula bone graft for arthrodesis of the shoulder. The construct was stabilized using a 4.5-mm pelvic reconstruction plate positioned on the scapular spine and the lateral aspect of the humerus. RESULTS A wide surgical margin was achieved in all patients. Two of them could be reintegrated and are able to work with excellent shoulder function. In one patient, who developed metastasis, a deep infection under chemotherapy 16 months after index surgery complicated the postoperative course. CONCLUSION The fibula's unique dual endosteal and periosteal blood supply makes it effective as a double-barrel bone graft for major long bone defects, which requires extra bone volume to prevent fractures until bone hypertrophy occurs. Additional bone and scar formation between the two struts are believed to provide a stable and long lasting construct, as seen in our patients.