Abstract
Purpose: To investigate the feasibility and accuracy of combining a personalized finite element analysis with 3D-printed navigation template on the treatment of femoral neck fracture (FNF) with cannulated screw. Methods: A total of 60 patients as unstable FNT with cannulated screw were evolved in this study from October 2016 to December 2019, who were randomly divided into two groups (n=30/group): The subjects in the study group were examined using the a finite element analysis according to the three-dimensional CT of hip joint before operation and then underwent 3D-printed navigation template of the femur to complete the implantation of the cannulated screw whereas the other 30 patients in the control group were underwent the implantation of the cannulated screw using the conventional FNF treatment in the inverted isosceles triangle. The success rate of one-time implantation of the cannulated screw, the postoperative shortest distance of talus cortex, and the healing of fracture, necrosis of femoral head and Harris function scores of hip joint in 12 months after operation were recorded and compared between the study and control groups.Results: According to the finite element analysis, the biomechanics of three screws were the most stable when they were close to the bone cortex (<3mm). Further more, it was demonstrated that the patients in the study group have more effectively success rate of one-time nail placement (93.33%) and significant reduction in the distance of talus cortex of cannulated screws (3.04 ± 0.39mm) than those in the control group (66.67% and 5.38±0.71mm). At 12 months post-surgery, higher healing rate of fracture (93.33%) and Harris functional score of hip (93.67 ± 4.01), as well as lower necrosis rate of femoral head (6.67%) were underwent in the study group when compared with the control group (83.33%, 91.57±4.18 and 16.67%). Conclusion: The results of this study suggest that combined application of a personalized finite element analysis and 3D-printed navigation template in the treatment of femoral neck fracture with cannulated screw can not only improve the effective nail placement, but also make the screw more in line with the requirements of biomechanical stability to promote the fracture healing and reduce the risk of femoral head necrosis. So it is a digital orthopedic technology for clinical popularization.
