Intercalary Reconstruction of the “Ultra-Critical Sized Bone Defect” by 3D-Printed Porous Prosthesis After Resection of Tibial Malignant Tumor

PURPOSE: This study aimed to evaluate the early stability, limb function, and mechanical complications of 3D-printed porous prosthetic reconstruction for “ultra-critical sized bone defects” following intercalary tibial tumor resections. METHODS: This study defined an “ultra-critical sized bone defect” in the tibia when the length of segmental defect in the tibia was >15.0 cm or >60% of the full tibia and the length of the residual fragment in proximal or distal tibia was between 0.5 cm and 4.0 cm. Thus, five patients with “ultra-critical sized bone defects” following an intercalary tibial malignant tumor resection treated with 3D-printed porous prosthesis between June 2014 and June 2018 were retrospectively reviewed. Patient information, implants design and fabrication, surgical procedures, and early clinical outcome data were collected and evaluated. RESULTS: Among the five patients, three were male and two were female, with an average age of 30.2 years. Pathological diagnoses were two osteosarcomas, one Ewing sarcoma, one pseudo-myogenic hemangioendothelioma, and one undifferentiated pleomorphic sarcoma . The average length of the bone defects following tumor resection was 22.8cm, and the average length of ultra-short residual bone was 2.65cm (range=0.6cm–3.8cm). The mean follow-up time was 27.6 months (range=14.0–62.0 months). Early biological fixation was achieved in all five patients. The average time of clinical osseointegration at the bone–porous interface was 3.2 months. All patients were reported to be pain free and have no limitations in their walking distance. No prosthetic mechanical complications were observed. CONCLUSION: Reconstruction of the “ultra-critical sized bone defect” after an intercalary tibial tumor resection using 3D-printed porous prosthesis achieved satisfactory overall early biological fixation and limb function. Excellent primary stability and the following rigid biological fixation were key factors for success. The outcomes of this study were supposed to support further clinical application and evaluation of 3D-printed porous prosthetic reconstruction for “ultra-critical sized bone defects” in the tibia.