Subject-specific models were developed and finite element analysis was performed to observe the effect of the frontal plane tibiofemoral angle on the normal stress, Tresca shear stress and normal strain at the surface of the knee cartilage. Finite element models were created for three subjects with different tibiofemoral angle and physiological loading conditions were defined from motion analysis and muscle force mathematical models to simulate static single-leg stance. The results showed that the greatest magnitude of the normal stress, Tresca shear stress and normal strain at the medial compartment was for the varus aligned individual. Considering the lateral knee compartment, the individual with valgus alignment had the largest stress and strain at the cartilage. The present investigation is the first known attempt to analyze the effects of tibiofemoral alignment during single-leg support on the contact variables of the cartilage at the knee joint. The method could be potentially used to help identify individuals most susceptible to osteoarthritis and to prescribe preventive measures.
Nicholas H. Yang (Corresponding Author) is with the Mechanical and Industrial Engineering Dept., Northeastern University, Boston, MA; Yang is now with Exponent, Inc. Paul K. Canavan is with the Physical Therapy Dept., Northeastern University, Boston, MA, and the Department of Physical Therapy, Windham Community Memorial Hospital, Windham, Connecticut. Hamid Nayeb-Hashemi is with the Mechanical and Industrial Engineering Dept., Northeastern University, Boston, MA.