Prediction of hip joint load and translation using musculoskeletal modelling with force-dependent kinematics and experimental validation

Musculoskeletal (MSK) lower limb models are widely used to predict the resultant contact force in the hip joint as a non-invasive alternative to instrumented implants. Previous MSK models based on rigid body assumptions treated the hip joint as an ideal sphere with only three rotational degrees of freedom (DOFs). An MSK model that considered force-dependent kinematics (FDK) with three additional translational DOFs was developed and validated in the present study by comparing it with a previous experimental measurement. A 32-mm femoral head against a polyethylene cup was considered in the MSK model for calculating the contact forces. The changes in the main modelling 28 parameters were found to have little influence on the hip joint forces (RDPV<10 BW%, mean trial deviation<20 BW%). The centre of the hip joint translation was more sensitive to the changes in the main modelling parameters, especially muscle recruitment type (RDPV<20%, mean trial deviation<0.02 mm). The predicted hip contact forces (HCFs) showed consistent profiles, compared with the experimental measurements, except in the lateral-medial direction. The ratio-average analysis, based on the Bland and Altman’s plots, showed better limits of agreement (LOA) in climbing stairs (mean LOA: -2.0 to 6.3 in walking, mean LOA: -0.5 to 3.1 in climbing stairs). Better agreement of the predicted HCFs was also found during the stance phase. The FDK approach underestimated the maximum hip contact force by a mean value of 6.68 ±1.75% BW compared with the experimental measurements. The predicted maximum translations of the hip joint centres were 0.125 ± 0.03 mm in level walking and 0.123 ± 0.005 mm in climbing stairs

Muscuskeletal model for Trend Validation of Metabolic Models Against Measurements Using Indirect Calorimetry

A muscuskeletal model made with Anybody Modeling Software used for the article "Trend Validation of Metabolic Models Against Measurements Using Indirect Calorimetry". The zip file contains the two items. A folder and a .py file. The .py file shows the use of AnyPyTools (can be installed with PIP) to run the AnyBody model with easy to use iterations. The folder contains several files and folders. The "Knee_eks_fleks_Model.Main.any" is the primary file for the model. KneeMetabolicTesting.any contains the relevant information regarding how to output the metabolic models

Gait alteration strategies for knee osteoarthritis: a comparison of joint loading via generic and patient-specific musculoskeletal model scaling techniques

Gait modifications and laterally wedged insoles are non-invasive approaches used to treat medial compartment knee osteoarthritis. However, the outcome of these alterations is still a controversial topic. This study investigates how gait alteration techniques may have a unique effect on individual patients; and furthermore, the way we scale our musculoskeletal models to estimate the medial joint contact force may influence knee loading conditions. Five patients with clinical evidence of medial knee osteoarthritis were asked to walk at a normal walking speed over force plates and simultaneously 3D motion was captured during seven conditions (0°-, 5°-, 10°-insoles, shod, toe-in, toe-out, and wide stance). We developed patient-specific musculoskeletal models, using segmentations from magnetic resonance imaging to morph a generic model to patient-specific bone geometries and applied this morphing to estimate muscle insertion sites. Additionally, models were created of these patients using a simple linear scaling method. When examining the patients’ medial compartment contact force (peak and impulse) during stance phase, a ‘one-size-fits-all’ gait alteration aimed to reduce medial knee loading did not exist. Moreover, the different scaling methods lead to differences in medial contact forces; highlighting the importance of further investigation of musculoskeletal modeling methods prior to use in the clinical setting

Gait alteration strategies for knee osteoarthritis: a comparison of joint loading via generic and patient-specific musculoskeletal model scaling techniques

Gait modifications and laterally wedged insoles are non-invasive approaches used to treat medial compartment knee osteoarthritis. However, the outcome of these alterations is still a controversial topic. This study investigates how gait alteration techniques may have a unique effect on individual patients; and furthermore, the way we scale our musculoskeletal models to estimate the medial joint contact force may influence knee loading conditions. Five patients with clinical evidence of medial knee osteoarthritis were asked to walk at a normal walking speed over force plates and simultaneously 3D motion was captured during seven conditions (0°-, 5°-, 10°-insoles, shod, toe-in, toe-out, and wide stance). We developed patient-specific musculoskeletal models, using segmentations from magnetic resonance imaging to morph a generic model to patient-specific bone geometries and applied this morphing to estimate muscle insertion sites. Additionally, models were created of these patients using a simple linear scaling method. When examining the patients’ medial compartment contact force (peak and impulse) during stance phase, a ‘one-size-fits-all’ gait alteration aimed to reduce medial knee loading did not exist. Moreover, the different scaling methods lead to differences in medial contact forces; highlighting the importance of further investigation of musculoskeletal modeling methods prior to use in the clinical setting