ObjectiveTo evaluate the effectiveness of three-dimensional (3D) printing navigation templates assisting reconstruction with personalized unrestricted total knee prosthesis to treat maliganant bone tumors around the knee. MethodsBetween March 2007 and September 2014, 43 patients with malignant tumor around the knee were divided into 2 groups: 3D printing navigation templates assisting reconstruction with personalized unrestricted total knee prosthesis were used in 21 cases (trial group), and conventional tumor resection and reconstruction with hinged total knee prosthesis were used in 22 cases (control group). There was no significant difference in age, gender, tumor location, pathological diagnosis, tumor stage, diameter of tumor, disease duration, and preoperative visual analogue scale (VAS) score between 2 groups (P>0.05), which were comparable. Intraoperative length of tumor resection and blood loss were recorded and compared, and the postoperative complications and tumor recurrence were observed. The Musculoskeletal Tumor Society (MSTS) score was used to evaluate knee joint function. ResultsThe operations were completed successfully in the patients of 2 groups and postoperative pathological results were negative in tumor resection margin. All the patients were followed up 12-77 months (mean, 36.7 months). There was no significant difference in the length of tumor resection and blood loss between trial group and control group (t=1.01, P=0.32; t=-0.76, P=0.45). In trial group, the resection range and reconstruction results were consistent with preoperative computer simulation; postoperative complications happened in 2 cases (9.52%); 1 case of immunological rejection and 1 case of infection); 2 cases (9.52%) had recurrence of osteosarcoma and pulmonary metastasis at 1 year after operation. In the control group, complication occurred in 6 cases (27.27%; 2 cases of periprosthetic fractures, 2 cases of infection, 1 case of incision nonunion, and 1 case of common peroneal nerve injury); 4 cases (18.18%) had recurrence of osteosarcoma and metastasis at 1 year after operation. There was no significant difference in postoperative complication and recurrence rate between 2 groups (χ2=2.24, P=0.14;χ2=0.67, P=0.41). At last follow-up, distal femur score of tumor and proximal tibial score of tumor in trial group were significantly better than those in control group (t=4.89, P=0.00; t=3.94, P=0.00). The mean flexion and extension range of motion of the knee joint was (115.45±12.25)° in trial group and was (101.49±11.96)° in control group, showing significant difference (t=3.78, P=0.00). ConclusionThe effectiveness using 3D printing navigation templates assisting reconstruction with personalized unrestricted prosthesis for maliganant bone tumors around the knee is better than conventional tumor resection and reconstruction with hinged total knee prosthesis. It can improve the joint function better and the patients' quality of life.