Patient-specific osteoarticular reconstruction of the proximal tibia for giant cell tumor using a 3D-printed trabecular implant and hinged knee arthroplasty: a case report.

Background: Giant cell tumor of bone (GCTB) is a benign but locally aggressive primary bone tumor that frequently affects the epiphyseal-metaphyseal region of long bones, particularly around the knee. In rare cases, it may undergo malignant trans-formation or metastasize. Case presentation: We report the case of a 62-year-old woman with a 5-year history of left knee pain, progressive deformity, and functional limitation. Imaging studies and biopsy confirmed a giant cell tumor of the proximal tibia with extensive epiphyseal involvement and articular collapse. The patient underwent oncologic resection using patient-specific cutting guides, followed by reconstruction with a custom 3D-printed porous trabecular Ti6Al4V-ELI implant manufactured by selective laser melting on a Renishaw AM400 system, combined with hinged total knee arthroplasty. The extensor mechanism was reinserted through dedicated fixation slots, and soft-tissue coverage was achieved with a medial gastrocnemius flap and polypropylene mesh. At 6 months, radiographs showed satisfactory alignment and early structural integration, with no evidence of local recurrence or implant loosening. Clinically, the patient achieved full weight-bearing and an excellent functional outcome. Conclusion: This case suggests that patient-specific reconstruction combining virtual planning, 3D printing, and porous trabecular design may be a feasible limb-salvage option for selected proximal tibial GCTB with major osteoarticular destruction.