Validation of Knee Load Predictions During a Dual Limb Squat and Calfrise

Knowledge of knee loading would benefit prosthetic design, development of tissue engineered materials, orthopedic repair, and management of degenerative joint diseases such as osteoarthritis. Musculoskeletal modeling provides a method for estimating in vivo joint loading, but validation of model predictions is challenging. Data provided by the “Grand Challenge Competition to Predict In-Vivo Knee Loads” for the 2012 American Society of Mechanical Engineers Summer Bioengineering Conference [1] provides data from an instrumented prosthetic knee that can be used to validate load predictions. The Grand Challenge data set includes implant and bone geometries, motion, ground reaction forces, electromyography (EMG) as well as measured knee loading. Presented here are muscle driven forward dynamics simulations with a prosthetic knee for two of the calibration gait trials (SC_2legsquat and SC_calfrise) provided with the Grand Challenge data set. The calibration trials include the instrumented knee measurements and are provided to help “calibrate” models used in the Grand Challenge competition. Inputs to model simulations were experimental marker motion and outputs included muscle force, ground reaction forces, ligament forces, contact forces, and knee loading. Experimental measurements of knee loading, ground reaction force, and muscle activations were compared to model predictions.