<![CDATA[Background: Giant Cell Tumor (GCT) is a non-metastatic bone tumor known for its local aggressiveness and recurrence risk. While commonly affecting the knee and distal radius, involvement of the distal fibula, particularly the lateral malleolus, is extremely rare. Standard surgical approaches may jeopardize joint mechanics in this critical load-bearing region. This case series highlights the application of ipsilateral autologous fibular head grafting to restore ankle stability following tumor resection. We aim to offer a practical reference for biological reconstruction in managing uncommon GCTs of the lateral malleolus.Case Presentation: Two female patients, aged 20 and 14 years old, presented with progressively enlarging, painful right lateral ankle masses. Both patients underwent Magnetic Resonance Imaging (MRI), revealing a well-defined lytic lesion with fluid-fluid levels and cortical thinning consistent with GCT. They underwent wide resection or reoperation followed by fibular head autograft, and one-third tubular plate (OTP) fixation. At 3-year and 6-month follow-up, both showed no recurrence and regained excellent function, with Musculoskeletal Tumor Society Score (MSTS) and American Orthopaedic Foot & Ankle Score (AOFAS) of 28/30, 94/100, and 26/30, 92/100, respectively.Conclusions: This case series supports the use of fibular head autografting as a joint-preserving solution following lateral malleolus GCT resection. Our findings provide preliminary evidence for a biologically favourable and functionally effective method applicable to similar rare presentations.]]>
