Abstract: Objective　To investigate the feasibility and effectiveness of 3D printing module for reconstruction of traumatic bone defects. 　Methods　A young female with an open fracture of the left knee associated with femoral condyle defect caused by traffic accident was included. The defect of lateral condyle of femur was repaired and reconstructed assisted by computer and 3D printing technique after the initial debridement and wound closure for 2 months, based on the original data of CT scans preoperative, the bone defect module and the femoral articular curvature surface model consistent with the anatomical shape of the healthy side were established by means of mirror operation, fusion registration and Boolean operation, and accurate preoperative planning was made. The corresponding 3D-module was made by rapid prototyping technology, and the femoral condyle of the defect was assisted to be shaped during the surgery, so as to achieve accurate repair and reconstruction of the bone structure. In the long-term follow-up after the operation, the effectiveness of the 3D printing module was evaluated by subjective sensation, image performance and HSS score.　Results　Postoperative follow-up was conducted from 1 month to 8 years, we detected that the pain, function, range of motion, muscle strength, knee flexion deformity and knee instability of the injured limb, and showed benign development. There were no significant adverse events or disabling factors except partial bone graft resorption, and the motor function of the injured limb met the needs of daily life during the follow-up. Postoperative follow-up of 1 month, 2 years and 8 years showed that the HSS scores were 44, 58 and 83 points, respectively.　Conclusions　3D printing module is a perfect way to assist intraoperative surgery because it can improve the accuracy of surgical operation for the repair and reconstruction of traumatic bone defects and provide new ideas for personalized treatment.

Key words: Bone defect, 　Rehabilitation and reconstruction, 　Structural bone graft, 　Computer aided, 3-D printing