An informational framework to predict reaction of constraints using a reciprocally connected knee model

Abstract

Researchers have used screw theory to describe the motion of the knee in terms of instantaneous axes of the knee (IAK). However, how geometric change to the dynamic alignment of IAK may affect stance phase of foot loading has not yet been fully explained. We have tested our informational framework through readily accessible benchmark data (Fregly et al. 2012): muscle contraction and ground reaction force are compounded into a wrench that is reciprocal to the IAK and resolved into component wrenches belonging to the reciprocal screw system. This revealed the special screw system that defines the freedom available to the knee and more precisely revealed how to measure this first order of freedom. After this step, we determined the reciprocal screw system, which involves the theory of equilibrium. Hence, a screw system of the first order will have a screw system of the fifth order as its reciprocal. We established a framework the estimation of reaction of constraints about the knee using a process that is simplified by the judicious generation of IAK for the first order of freedom in equilibrium.

Keywords::

• instantaneous axes of the knee (IAK)
• osteoarthritis
• perception–action coupling manifold
• Gibson's theory of affordance
• Ball's screw theory

Acknowledgements

We would like to thank Professor B.J. Fregly of the University of Florida for making his data available to us. The first author extends thanks to Ms. Maria do Amparo of the FMH library for her prompt services. The first author also thanks his mother, Ms. Soonhee Won, for her continuous encouragement for this research. The experimental data that we used for validation of our approach were provided by the ‘Grand Challenge Competition to Predict In Vivo Knee Loads’, the latter was part of the Symbiosis project that was funded by the National Institutes of Health via the NIH Roadmap for Medical Research (Grant U54 GM072970).