Surgical Technique and Outcome of Joint Sparing Limb Salvage Surgery by Three-dimensional-printed Prothesis for Children With Osteosarcoma in Distal Femur

Purpose The purpose of this study was to introduce the surgical technique and functional outcome of joint-sparing limb salvage surgery with metaphyseal osteotomy by dependent design of three-dimensional printed prothesis for children with osteosarcoma in distal femur.Methods Between 2012 to 2019, we performed twelve joint sparing limb salvage surgeries (JSLSS) with metaphyseal osteotomy for the children of osteosarcoma in the distal femur with our dependent design of 3D-printed guided plate and prothesis. The clinical assessment including resection margin, limb-length discrepancy, orthopaedic complications and functional outcome would be analyzed.Results The mean operation time for JSLSS was 107.6 minutes and the average blood loss was 194.5ml with the dependent design of 3D-printed prosthesis. With the assistance of guide plate, the mean margin of the osteosarcoma from the epiphyseal plate was 1.6 cm and the mean limb-length discrepancy was 2.2 cm with maximum follow-up period of seven years (mean 45.3 months, range 12-84 months). All the patients could bend their knee through >90° flexion, achieved similar results for ROMs in 6DOF during gait compared with normal data of Chinese knees, and the mean MSTS score was 94.7 for the patients with JSLSS. One patient had a superficial infection and there was one patient of local recurrence happened during the follow-up with the necrosis rate less than 90% by preoperative chemotherapy. None aseptic loosening happened in distal femur for the patients in this group with dependent design of 3D-printed prosthesis.Conclusion Joint-sparing limb salvage surgery by metaphyseal osteotomy with the dependent design of 3D-printed prosthesis and guide plate would be a good choice for the children with osteosarcoma in distal femur.