August 1, 2013.
Quantitative data of stresses and strains in the cartilage of the knee and hip joints are required to design prostheses and can be used to give accurate advice to patients with cartilage damage as to which activities should be avoided. Instrumented hip implants can only give the overall resultant force in the joint, not the stresses and strains throughout the cartilage. Finite Element (FE) models of the Knee and Hip are being constructed in order to obtain the stresses and strains in articular (of the joint) cartilage. Muscle forces and joint contact forces are required as inputs to these FE models. OpenSim is an open-source program containing a musculoskeletal system of the human body. Using OpenSim, muscle forces, their attachment points, their lines of action and joint contact forces were obtained for various time-steps during the gait cycle and during standing. Calculated and experimental joint contact forces were compared. Instrumented prostheses have determined the max joint contact force is 2.5-3.3 times bodyweight for walking and approximately 1.0 for standing. Our max joint contact forces were 3.8 times bodyweight for the hip, 3.1 for the knee during walking and 1.4 for the hip and 1.3 for the knee during standing.
Biomechanical Engineering | Biomechanics and Biotransport | Computer-Aided Engineering and Design
Scott J Hazelwood
California Polytechnic State University (Cal Poly SLO)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).