Comparison Between Methods to Create the Leg Length Discrepancy (LLD) Patient-Specific Model: Musculoskeletal Modeling

The purpose of this study was to compare the image-based and marker-based scaling methods to create subject-specific models for LLD children. One of the important applications of subject-specific models is gait analysis of the leg length discrepancy (LLD) patients. The LLD is defined as a situation in which the paired lower body segments have a noticeably unequal length. Twenty-two children were categorized to normal and LLD (average more than 1 cm) groups (Normal: 11 and LLD: 11) who participated in this study. The Gait2354_Simbody model of OpenSim consists of joints with 23 degrees of freedom and 92 muscle-tendon actuators to represent 76 muscles in the lower extremities and torso was used to simulate the gait. Significant differences were found between normal and LLD children in total square error and RMS of marker error (p < 0.05). This study demonstrates the feasibility of using musculoskeletal modelling to compare methods to create patient-specific model in patients with knee height asymmetry.