Immediate effects of valgus knee bracing on tibiofemoral contact forces and knee muscle forces

Abstract

Electromyography-driven model is a unique tool to study bracing  Minimal, but variable, brace effect on medial knee joint contact force  Mechanistic studies are required in people with knee osteoarthritis ABSTRACT Background: Valgus knee braces have been reported to reduce the external knee adduction moment during walking. However, mechanistic investigations into the effects of valgus bracing on medial compartment contact forces using electromyogram-driven neuromusculoskeletal models are limited. Research question: What are the immediate effects of valgus bracing on medial tibiofemoral contact forces and muscular loading of the tibiofemoral joint? Methods: Sixteen (9 male) healthy adults (27.7±4.4 years) performed 20 over-ground walking trials at self-selected speed both with and without an Ossür Unloader One® brace. Assessment order (i.e., with or without brace) was randomised and counterbalanced to prevent order effects. While walking, threedimensional lower-body motion, ground reaction forces, and surface electromyograms from eight lower-limb muscles were acquired. These data were used to calibrate an electromyogram-driven neuromusculoskeletal model of muscle and tibiofemoral contact forces (N), from which muscle and external load contributions (%) to those contact forces were determined. Results: Although walking with the brace resulted in no significant changes in peak tibiofemoral contact forces at the group-level, individual responses were variable and non-uniform. At the grouplevel, wearing the brace resulted in a 2.35% (95% CI 0.46-4.24; p=0.02) greater relative contribution of muscle to lateral compartment contact loading (54.2±11.1%) compared to not wearing the brace (51.8±12.1%) (p<0.05). Average relative contributions of muscle and external loads to medial compartment loading were comparable between brace and no brace conditions (p≥0.05).

Modelling the loading mechanics of anterior cruciate ligament

“…To calculate 6 generalized loads (moments and forces in each three planes of motion) at knee, ankle, and hip, we modified the generic model. At the knee, we added dummy bodies of negligible mass/inertia and associated universal joints to the generic model topology(42,43), but preserved the original knee mobility: flexion/extension with abduction/adduction, internal/external rotation, superior-inferior translation, and anterior/posterior translations prescribed as functions of knee flexion(44). At the ankle and hip, generic joints were expanded to 6 DOFs, but the newly expanded DOFs had zero mobility space.…”

Machine learning methods to support personalized neuromusculoskeletal modelling

“…Computational neuromusculoskeletal biomechanics aims to understand and manage many neuromusculoskeletal conditions, and to rehabilitate patients and have been used to study many phenomena ranging from muscle function during locomotion in healthy individuals (Hamner et al 2010;Killen et al 2018;Pandy and Andriacchi 2010;Sasaki 2010;Saxby et al 2016b;Schache et al 2012;Shelburne et al 2006;Thelen and Anderson 2006) and those with pathologies (Gerus et al 2013;Hoang et al 2019;Konrath et al 2017;Montefiori et al 2019a;Saxby et al 2016a;Shao et al 2009), to model-driven control of prostheses or rehabilitation robotics (Sartori et al 2018;Sartori et al 2016). Other applications include estimation of tissue loading (Kim et al 2009;Saxby et al 2016b;Wellsandt et al 2016) and how this is effected by ergonomic aids (Hall et al 2019) or occupational demands (Lenton et al 2018). Musculoskeletal loading (Pena et al 2006;Shim et al 2016;Yang et al 2010) is of particular clinical interest, as loading has mechanistic links to tissue remodelling (Andriacchi et al 2009;Eskelinen et al 2019;Gardiner et al 2016;Myller et al 2019;Pizzolato et al 2017a;Smith et al 2013) (Saxby et al 2017Young People With Old Knees Research et al 2017) and is therefore a logical target for physical therapy.…”

Neuromusculoskeletal Modeling-Based Prostheses for Recovery After Spinal Cord Injury

“…The skeletal system is defined by multiple segments (i.e., bones) connected by three-dimensional joints mobilized accordingly to their anatomical function (Seth et al, 2018). EMG-informed NMS models have been used to successfully estimate muscle forces, joint contact forces, and joint stiffness in the lower and upper limbs of individuals with a variety of neuromuscular conditions (Sartori et al, 2015; Konrath et al, 2017; Hall et al, 2018; Hoang et al, 2018, 2019; Lenton et al, 2018; Kian et al, 2019). NMS models are the optimal platform for integration of multiple assistive devices, enabling physics-based sensor fusion, where input and output quantities are mechanistically and causally related.…”