ABSTRACT
Objective To research and prepare the individualized knee in vitro guided plate by 3D printing technique and to investigate the feasibility of its application in 8-plate epiphysiodesis.Methods Twelve children patients with knee varus or valgum in our hospital from January 2014 and November 2016,7 boys and 5 girls,average age of 8.2 years old,were performed the lower extremity continuous spiral CT scanning in the knee straight position.The Dicom format stored CT data were imported into software Mimics 15.0 for reconstructing the knee joint 3D model.The knee joint data after reconstruction were guided into software Geomagic1 1.0 with the.stl format.According to the demand that screws without perforating epiphyseal and joint surface,paralle ling to the epiphyseal and locating in the anterior-posterior median line of epiphyseal,the 8-plate placing screw navigation template was designed and printed by using the 3D printing technique;the 8-plate plate and screw internal fixation was conducted by intraoperative template location.The placed screw position was evaluated by postoperative CT.Results The imaging identification showed that 8-plate epiphysiodesis by using 3D printing individualized in vitro guided plate had accurate screw placement.The cases were followed from 6 months to 2 years,the satisfactory orthopedic effect was obtained in all cases.Conclusion Preparing the individualized knee in vitro guided plate by applying 3D printing technique in assisted 8-plate epiphysiodesis for treating child knee varus or valgum has accurate screw position and satisfactory effect.