Background  Artificial total femoral replacement has played an important role in limb reconstruction, but due to its difficulty in surgery and the particularity of prostheses, there are relatively few reports.

  Objective  To investigate the application value and efficacy of the combined artificial total femur prosthesis in patients with femoral malignancy.

  Methods  Clinical data about 12 patients with bone malignant tumors who underwent artificial total femoral replacement in the First Medical Center of Chinese PLA General Hospital from January 2014 to January 2018 were retrospectively analyzed. The Watson-Jone incision was mainly used for surgery, with the distal end extending to the lateral side of the patella revealing the full length of the femur, and the combination of prosthesis replacements was performed. Pain was evaluated by visual analogue scale (VAS) before operation and at 3 months after operation. At the last follow-up, the lower extremity function (MSTS) score, hip function Harris score (HHS), Oxford score and University Knee Score (OKS) were used to evaluate lower limb function, and imaging technologies were used to review tumor recurrence and metastasis.

  Results  There were 5 males and 7 females, with the average age of 27.75 years (range: 11-69 years). The course of disease ranged from 2 to 8 months, with an average of 4.4 months. There were 8 cases of osteosarcoma (7 cases of Enneking ⅡB stage, 1 case of Ⅲ stage), 3 cases of Ewing sarcoma (Enneking ⅡB stage), and 1 case of renal carcinoma with femoral metastases and pathological fractures. All patients were followed up for 17-81 months, with an average of 37.8 months. Among them, 2 patients died of multiple organ failure due to tumor metastasis, and 1 patient with metastatic cancer died due to the progression of the primary tumor and ineffective treatment. One case of Ewing sarcoma developed bone metastases and survived with the tumor. All patients had no local recurrence, infection, dislocation and other complications. The 5-year overall survival rate was 69.44%, and the tumor-free survival was 35 months. The 5-year overall survival rate was 69.44%, and the median tumor-free survival was 35 months. The VAS score at 3 months after surgery was significantly improved compared with the preoperative score (2.0 ± 1.08 vs 5.42 ± 1.32, P<0.001). At the last follow-up, the MSTS score, HHS score and Oxford University knee joint function score were significantly higher compared with before surgery (20.92 ± 3.25 vs 11.17 ± 3.26, P=0.002; 68.33 ± 12.19 vs 29.75 ± 11.40, P=0.003; 32.50 ± 7.48 vs 15.83 ± 5.27, P=0.002).

  Conclusion  Artificial total femur replacement can restore the anatomy of patients with primary tumor resection, rebuild the femur, preserve the patient's lower limb movement and weight-bearing capacity, and significantly improve the patient's quality of life.