A Novel Approach to Proximal Humerus Giant Cell Tumor: Cement Spacer and Screw Interdigitation for Optimal Stability.

Introduction: Giant cell tumor (GCT) of bone is a benign yet locally aggressive tumor that predominantly affects the epiphyseal/metaphyseal regions of long bones. While GCTs frequently occur around the knee or sacrum, their presentation in the proximal humerus is rare. Management of Campanacci Grade 3 GCTs poses challenges in achieving tumor control while preserving joint function. This case highlights a successful, minimally invasive approach to treating a proximal humerus GCT in an immunocompromised young patient. Case Report: A 30-year-old male presented with pain and restricted right shoulder movement following trivial trauma. Examination revealed bony-hard swelling and a restricted range of motion without neurovascular deficits. Imaging showed an expansile, lytic lesion in the proximal humerus with a cortical breach (Campanacci grade 3). Histopathological evaluation confirmed the diagnosis of GCT.The patient underwent intralesional curettage, reconstruction using a sandwich technique with sub-chondral bone graft, interdigitating cancellous screws in a cross-beam construct, and bone cement for filling the cavity. Adjuvants, including hydrogen peroxide and high-speed burring, were used to achieve negative margins and further reduce the risk of recurrence, given that intra-lesional curettage was used ahead of wide resection. The cross-beam construct of screws within the cavity not helped decrease surgical time and morbidity but provided a similar level of stability and decreased the risk of post-operative fractures.Postoperatively, the patient was immobilized for 6 weeks, followed by progressive mobilization. At 1.5 years follow-up, imaging showed no recurrence, and the patient achieved a painless, acceptable range of motion. Conclusion: This case underscores the potential of joint-preserving surgery for Campanacci grade 3 GCTs, particularly in younger patients. The combination of intralesional curettage, sandwich reconstruction, and interdigitating screws provided stable fixation with minimal morbidity. This approach preserved shoulder function, avoided the need for arthroplasty, and minimized surgical complications, even in a patient with compromised immunity. The findings support the use of innovative reconstruction techniques for aggressive GCTs, offering improved functional outcomes and reduced recurrence risk.