Individuals with knee osteoarthritis demonstrate increased passive stiffness of the hip flexor muscles

Preece, SJ ORCID: https://orcid.org/0000-0002-2434-732X, Alghamdi, W and Jones, R ORCID: https://orcid.org/0000-0001-5242-185X 2023, 'Individuals with knee osteoarthritis demonstrate increased passive stiffness of the hip flexor muscles' , The Knee, 41 , pp. 302-310.

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Abstract

Background: People with knee osteoarthritis stand and walk with increased trunk flexion. This altered postural alignment will increase hamstring activation, elevating mechanical knee loads during walking. Increased hip flexor stiffness may lead to increased trunk flexion. Therefore, this study compared hip flexor stiffness between healthy individuals and individuals with knee osteoarthritis. This study also sought to understand the biomechanical effect of a simple instruction to reduce trunk flexion by 5° during walking. Methods: Twenty individuals with confirmed knee osteoarthritis and twenty healthy individuals participated. The Thomas test was used to quantity passive stiffness of the hip flexor muscles and 3D motion analysis used to quantify trunk flexion during normal walking. Using a controlled biofeedback protocol, each participant was then instructed to decrease trunk flexion by 5°. Results: Passive stiffness was larger in the group with knee osteoarthritis (effect size = 1.04). For both groups, there was relatively strong correlation between passive stiffness and trunk flexion in walking (r=0-61-0.72). The instruction to decrease trunk flexion produced only small, non-significant, reductions in hamstring activation during early stance. Conclusions: This is the first study to demonstrate that individuals with knee osteoarthritis exhibit increased passive stiffness of the hip muscles. This increased stiffness appears to be linked to increased trunk flexion and may therefore underlie the increased hamstring activation which is associated with this disease. As simple postural instruction does not appear to reduce hamstring activity, interventions may be required which can improve postural alignment by reducing passive stiffness of the hip muscles.

Item Type:	Article
Schools:	Schools > School of Health Sciences
Journal or Publication Title:	The Knee
Publisher:	Elsevier
ISSN:	0968-0160
Depositing User:	SJ Preece
Date Deposited:	01 Mar 2023 08:50
Last Modified:	01 Mar 2023 09:00
URI:	https://usir.salford.ac.uk/id/eprint/66505

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