Subject: ScienceDirect - Clinical Biomechanics : Alterations in lower extremity movement and muscle activation patterns in individuals with knee osteoarthritis

 doi:10.1016/j.clinbiomech.2003.08.007      

Published by Elsevier Science Ltd.

Alterations in lower extremity movement and muscle activation patterns in individuals with knee osteoarthritis

John D. Childs, Patrick J. Sparto, G. Kelley Fitzgerald, Mario Bizzini and James J. Irrgang

Department of Physical Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh PA, USA

Received 24 February 2003;  accepted 15 August 2003. ; Available online 26 September 2003. 

Abstract

Objective. The purpose of this study was to investigate lower extremity movement and muscle activation patterns in individuals with knee osteoarthritis and healthy age- and gender-matched control subjects.

Design. This study utilized a non-randomized case-control design to compare 24 subjects with unilateral symptomatic knee osteoarthritis to 24 age- and gender-matched control subjects without knee osteoarthritis.

Background. It is hypothesized that knee osteoarthritis is associated with altered lower extremity movement and muscle activation patterns.

Methods. A gait analysis was performed to determine the lower extremity movement and muscle activation patterns when walking on a level surface at 1.12 to 1.34 m/s and while descending a 20 cm step. Paired t-tests were used to compare the average of five trials between the groups.

Results. Subjects with knee osteoarthritis demonstrated less excursion of the knee in the sagittal plane from heelstrike to peak flexion before midstance (i.e. during loading). Subjects with knee osteoarthritis also demonstrated reduced peak vertical ground reaction forces relative to body weight. The muscle activity patterns were also different between the groups. The vastus lateralis, medial hamstrings, tibialis anterior and medial gastrocnemius were on approximately 1.5 times longer than the same muscles in the control subjects. Additionally, significant increases in muscle co-activation were also observed in individuals with knee osteoarthritis during walking. Similar findings were observed when the subject descended a 20 cm step.
Relevance

Individuals with knee osteoarthritis utilize different movement and muscle activation patterns when walking and descending a step. The alterations may interfere with the knee’s ability to dissipate loads, which could lead to progression of the disease.

Author Keywords: Kinematics; Loading; Knee; Osteoarthritis; Gait

Article Outline

1. Introduction

2. Methods

3. Subjects

4. Equipment

5. Testing procedures

6. Data management and analysis

7. Results

8. Discussion

Acknowledgements

References