A 40-year-old woman with a recurrent, aggressive Giant Cell Tumor (GCT) of the distal femur presenting as a large lytic defect with posterior cortical destruction. The challenge lay in achieving long-term biomechanical stability and biological integration in this major load-bearing joint, where conventional endoprostheses and allografts have known limitations. Resection of the tumor required a substantial defect replacement. A 3D-printed titanium patient specific implant made for the precise condylar geometry, enhanced by an embedded fibular graft for biological osseointegration, and fastened with a custom titanium plate was the innovative patient-specific approach used for reconstruction. The patient had full, unrestricted weight-bearing and full functional recovery by 18 months, with no indications of tumor recurrence, according to postoperative follow-up, which showed full structural integration at six months. For intricate, high-stress orthopedic reconstructions, this case demonstrates the clinical effectiveness of combining biological augmentation with customized additive manufacturing. 

Case Presentation 

A 40-year-old female patient presented to the orthopedic oncology service with a six-month history of recurrent, progressively worsening pain and swelling in the left knee. Clinical examination revealed localized warmth and tenderness over the distal femur. Her ambulation was severely limited due to pain on weight-bearing. 

• Radiologic Findings: X rays, magnetic resonance imaging (MRI), and computed tomography (CT) scans confirmed a large, lobulated, and expansile lytic lesion, measuring approximately 66 mm×53 mm×44 mm, involving the medullary cavity of the distal femoral epiphysis and metaphysis. Key findings included thinning and focal destruction of the posterior cortex, soft tissue bulging, and a multicystic appearance with fluid-fluid levels, consistent with an aggressive, benign process, likely GCT. The lesion did not involve the articular surface, which preserved the possibility of a joint-sparing reconstruction. 

• Initial Management: Due to the size, recurrence, and associated structural compromise of the load-bearing condylar region, surgical excision with limb salvage was indicated. 

Management and Surgical Intervention 

Virtual Surgery Planning 

Given the massive bone loss and the need for a solution that offered both immediate mechanical support and long-term biological stability (preventing late failure associated with allografts or stress shielding from bulk prostheses), a custom-designed, patient specific implant (PSI) strategy was chosen. 

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Patient Specific Implant Design and Fabrication 

The exact resection margins were defined using virtual surgical planning. Curewith3D created a custom 3D-printed porous titanium implant that was precisely matched to the geometry of the native bone. The implant featured a controlled porous structure (pore size 1.0−1.5 mm) to promote vascularization and new bone ingrowth (osseointegration). 

Procedure 

The tumor was excised via a medial approach. Following tumor resection and chemical cauterization of the cavity to minimize recurrence risk, reconstruction was performed. 

• A patient specific implant was inserted to restore the condylar anatomy. 

• A fibular graft was harvested and placed into the patient specific implant to serve as a cortical strut, which promotes and enhances the osteointegration of the bone and provides additional internal structural support. 

• The construct was secured with a specially designed titanium fixation plate to ensure rapid, stable, and rigid fixation. 

Outcome and Follow-up 

Postoperatively, the patient was immobilized briefly before initiating progressive mobilization protocols. 

Time Point	Clinical and Radiographic Outcome
Day 23	Progressive mobilization commenced.
6 Weeks	Full weight-bearing capability achieved with assistance (walker).
6 Months	Follow-up radiographs demonstrated complete structural integration of the patient specific implant and incorporation of the fibular graft; no radiographic evidence of tumor recurrence.
18 Months	Patient achieved full functional recovery and was cleared for unrestricted activity. The knee joint demonstrated excellent stability and range of motion.

Discussion 

The effectiveness of a custom surgical solution for a challenging orthopedic oncology issue is demonstrated in this case.  The significant drawbacks of traditional techniques are addressed by the combination of a biological fibular graft and a 3D-printed lattice metal patient specific implant: 

• Superiority in Biomechanics:  Compared to commercially available endoprostheses, the PSI offered an immediate load distribution and an accurate anatomical fit. 

• Biological Durability: By stimulating robust osseointegration—a characteristic absent from metallic megaprostheses—the porous lattice structure and the embedded fibular graft reduced the long-term risks of aseptic loosening and poor graft incorporation prevalent in bulk allografts (Table 1). 

This hybrid approach is a viable, cutting-edge alternative for large distal femoral defects, as evidenced by the successful restoration of a high-stress articular and metaphyseal segment with sustained function and no recurrence at 18 months. Further study is warranted to confirm long-term outcomes across a broader patient cohort. 

Table 1. Comparative Analysis of Reconstruction Methods 

Reconstruction Method	Mechanical Stability	Osseointegration	Load-Bearing Potential
Megaprosthesis	High	None	Limited
Bulk Allograft	Moderate	Variable	Limited
3D-Printed Patient Specific Implant + Fibula Graft	High	Strong	Excellent

Reference:  

Chaudhry A, Sambharia AK, Bahre B, Pandey M, Chawla T. Reconstruction of a large distal femoral giant cell tumor using a 3D-printed condylar support lattice metal implant and fibular grafts: a novel biomechanical and surgical approach. 3D Print Med. 2025 Jul 16;11(1):38. doi: 10.1186/s41205-025-00282-x. PMID: 40668339; PMCID: PMC12265116. (Link)