How reliably can the properties of knee ligaments be predicted by optimization?!
Patient-specific FE models of the knee joint are highly of interest for more efficient clinical decision-making, due to the large variation in geometry and tissue properties between individuals.
Although the geometrical representation of the three-dimensional reconstruction can be achieved relatively easily, the development of an accurate finite element model of the knee joint (Fig.1) is still a complex task. The ligaments of the knee are among the most complicated structures to simulate, and at the same time most critical in determining the biomechanics of the joint. Reliable material properties obtained through experimental mechanical testing are needed in order to have a realistic response of the joint as predicted by the numerical models.
There is no accurate non-invasive way to measure the mechanical properties of the knee ligaments in vivo. Optimization based on laxity tests, by applying moments and forces to the joint and measuring the rotations and translations, may be a suitable approach to estimate the properties. The reliability and accuracy of the ligament properties estimated by optimization, however, is yet to be confirmed.
The aim of the study is to measure the mechanical tensile properties of the knee ligaments (Fig.2), in order to have a cadaver-specific ligament model, and to compare the optimized FE model of ligaments (Fig.1) with the real measured properties.
Fig.1: Knee FE model developed in ORL, Nijmegen.
Fig.2: General ligament tensile test set-up (left); ligament failure(right) (Stabuli et al. 1999)
Hamid Naghibi Beidokhti
Radboud university medical center
Department of Orthopedic Research Lab
Phone: +31 (0)24 361 73 79