Cruciate Ligament Behaviour Analysed with Modelling and Simulation of the Human Knee

Human joints are complex in structure and function that allow us a variety of activities with safe mobility and stability. However, the joints are prone to injuries that can affect life severely. Computer-based methods can be useful tools to understand the behaviour of the joints. Computational complexities in modelling and simulation can be overcome, to some extent, using input from related experimental work. Computational approach of modelling and simulation is useful in many areas including analysis of various activities, mechanisms of injuries during specific sports, designing of safe exercises, understanding effects of surgical procedures, etc. In the present study, a model of the knee is used to simulate a knee laxity test used to judge ligament integrity. Results of simulation are comparable to that of similar experiments on cadaver knees. For example, lower bone of the model knee moved 3.4, 6.1 and 5.3 mm anterior to the upper bone, respectively, at 0°, 45° and 90° flexion of the joint resulting from an external 150 N force on the lower bone. These movements were similar to those from experiment. Further, the model calculations suggest that effectiveness of the external force in translating the bone diminished with increasing force magnitude. The analysis suggests that knee ligaments may be predisposed to injury during specific situations like playing football. The results have clinical relevance.