Finite Element Analysis-Based Pre-operative Application for Biomechanical Evaluation of a Locking Plate Used in Reconstruction After En Bloc Resection of a Stage 3 Giant Cell Tumor of the Distal Radius

Abstract

The subject of the study was a pre-operative application involving the use of a locking plate in reconstruction after en bloc resection of a Stage 3 giant cell tumor from the distal radius in a 60-year-old male patient. The essence of the application was the use of finite element analysis to determine stresses in and deformations of the bone, plate, and screws. A model of the distal radius was constructed using CT data from a specific patient and the type and magnitude of the loading on the system were those experienced by the patient during the post-surgery period.  The boundary conditions used were consistent with the aforementioned loading. Several parameters were selected as adjustable parameters in the application builder toolbox. The maximum deformation of the plate was 5.05 mm. The maximum von Mises stress was 75.06 MPa in the bones and 1,123.35 MPa in the plate. A loosened screw was located at the proximal zone of the plate, with the maximum pull-out force in the screw being 679.35 N. This was comparable to the value obtained from experimental tests, thus validating the FEA results. The maximum von Mises stress in the system exceeded the yield strengths of the bones and of the plate material (Ti-6Al-4V).  The proposed application may be used by orthopedic surgeons to visualize the biomechanical performance of the bones-locking plate-screws system and to guide patients for loading actions to avoid or limit in the post-surgery period.