The performance of total knee replacement implants is sensitive to intersubject and surgical variability. Subject-specific finite element (FE) analyses have been used to evaluate the joint mechanics of implant designs. This case study highlights the development of an FE platform to perform population-based evaluations of implant in activities of daily living and considering the impact of variability.
Center for Orthopaedic Biomechanics, University of Denver:
P.J. Laz • C.K. Fitzpatrick • P.J. Rullkoetter
Detailed representations of the structures of the knee, including femur, tibia, patella and associated cartilage and ligaments, were segmented from magnetic resonance (MR) images using ScanIP. This was performed for 40 subjects to serve as a training set for a statistical shape model. In addition, a complete model of the bones and muscles of the lower limb were developed from cryosection slice images of the visible human
Statistical shape modelling characterizes the common modes of variation in the training set geometries. The model is created by establishing correspondence between nodes and then performing a principal component analysis. The shape model results in a series of modes characterizing the changes in geometry and alignment. As the statistical shape model is based on an FE mesh, the platform integrates seamlessly into analysis and can generate new instances to facilitate population-based investigations.