Three dimensional finite element analysis of nitinol patellar concentrator in treatment of patellar fracture / 第二军医大学学报

ABSTRACT

Objective: To analyze the design of Nitinol Patellar Concentrator (NT-PC) and its biomechanic characteristics for treating comminuted patellar fractures.Methods:NT-PC and patellar was analyzed by ANSYS software,the finite element was three dimension brick unit with 20 nodes, 8 faces, and the degree of freedom was 6.In NT-PC,10 483 units were divided and the number of nodes was 17 959;In Patellar,8 775 units were divided and the number of nodes was 15 847.The patellar model was loaded according to the 5 converging directions of NT-PC.Results:NT-PC had tension force on its internal face and pressure force in its external face.The maximum value was 195.8 MPa and -18 MPa,which was far from its utmost stress and fatigue limit.The memory converging force of NT-PC was 134 N.The stress (0.8 MPa) was evenly distributed on the patellar surface.Stress calculation of every node indicated that positive stress was the main stress.Conclusion: The design of NT-PC is reasonable and has good reusing character.After fixation, exercise is allowed immediately after operation.The continual positive stress is good for the stability of fracture end and fracture healing.