en تومور Tumor surgery گزارش مورد Case Report <div style="text-align: justify;"><strong>Background</strong>: Osteosarcoma is the most common primary malignant bone tumor; however, involvement of the distal radius is rare, accounting for less than 1% of cases. Reconstruction following wide resection in this anatomical region is technically challenging because of limited soft tissue coverage, complex wrist biomechanics, and the need to preserve upper limb function. Free vascularized fibular grafting has emerged as a reliable option for biological reconstruction of large skeletal defects. &nbsp;&nbsp;<br> <strong>Case Presentation</strong>: We reported the case of a 20-year-old male who presented with progressive pain, swelling, and deformity of the right wrist. Imaging studies revealed a destructive lesion of the distal radius with soft tissue extension. Core needle biopsy confirmed the diagnosis of osteosarcoma. After receiving neoadjuvant chemotherapy, the patient underwent wide tumor resection followed by reconstruction using a free vascularized fibular graft. Microvascular anastomosis was performed to recipient vessels at the wrist, and the graft was stabilized with internal fixation. Histopathological examination confirmed tumor-free surgical margins. Radiographic union was achieved during follow-up, and the patient regained satisfactory wrist stability and functional use of the hand. No evidence of local recurrence, infection, or distant metastasis was observed at the latest follow-up.<br> <strong>Conclusion</strong>: Free vascularized fibular grafting represents a reliable biological reconstruction technique for distal radius osteosarcoma, providing durable structural support and acceptable functional outcomes following oncologic resection.&nbsp;</div> Osteosarcoma, Distal Radius, Vascularized fibular graft, Biological reconstruction, Limb-salvage surgery, Bone tumor reconstruction 145 150 http://jros.iums.ac.ir/browse.php?a_code=A-10-1606-2&slc_lang=en&sid=1 Khalil Kargar Shooroki khalilkargar63@yahoo.com 10031947532846008666 10031947532846008666 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Sam Hajialiloo Sami Saamhaji@gmail.com 10031947532846008667 10031947532846008667 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. amin hamidzadeh Khiavi drahkh2000@gmail.com 10031947532846008668 10031947532846008668 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. alireza moazen alirezamzn2022@gmail.com 10031947532846008669 10031947532846008669 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. yousef barati us.myousef@gmail.com 10031947532846008670 10031947532846008670 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. babak roshanravan babak.137595@yahoo.com 10031947532846008671 10031947532846008671 Yes Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.