HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) The Bottom Line All Versions of this Article: ptj.20070295v1 89/10/1072    most recent Submit a response Alert me when this article is cited Alert me when Rapid Responses are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Valtonen, A. Articles by Sipilä, S. PubMed PubMed Citation Articles by Valtonen, A. Articles by Sipilä, S. Related Collections Gait Disorders Kinesiology/Biomechanics Injuries and Conditions: Knee Geriatrics: Other Social Bookmarking                      What's this?

Muscle Deficits Persist After Unilateral Knee Replacement and Have Implications for Rehabilitation

A. Valtonen, PT, MSc, is Researcher, Rehabilitation and Pain Unit, Kymenlaakso Central Hospital, Kotkantie 41, FIN-48210 Kotka, Finland, and Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
T. Pöyhönen, PT, PhD, is Exercise Physiologist, Rehabilitation and Pain Unit, Kymenlaakso Central Hospital.
A. Heinonen, PT, PhD, is Professor, Department of Health Sciences, University of Jyväskylä.
S. Sipilä, PT, PhD, is Research Director, Finnish Centre for Interdisciplinary Gerontology, Department of Health Sciences, University of Jyväskylä.

Address all correspondence to Ms Valtonen at: anu.m.valtonen{at}jyu.fi

Background: Knee joint arthritis causes pain, decreased range of motion, and mobility limitation. Knee replacement reduces pain effectively. However, people with knee replacement have decreases in muscle strength ("force-generating capacity") of the involved leg and difficulties with walking and other physical activities.

Objective and Design: The aim of this cross-sectional study was to determine the extent of deficits in knee extensor and flexor muscle torque and power (ability to perform work over time) and in the extensor muscle cross-sectional area (CSA) after knee joint replacement. In addition, the association of lower-leg muscle deficits with mobility limitations was investigated.

Methods: Participants were 29 women and 19 men who were 55 to 75 years old and had undergone unilateral knee replacement surgery an average of 10 months earlier. The maximal torque and power of the knee extensor and flexor muscles were measured with an isokinetic dynamometer. The knee extensor muscle CSA was measured with computed tomography. The symmetry deficit between the knee that underwent replacement surgery ("operated knee") and the knee that did not undergo replacement surgery ("nonoperated knee") was calculated. Maximal walking speed and stair-ascending and stair-descending times were assessed.

Results: The mean deficits in knee extensor and flexor muscle torque and power were between 13% and 27%, and the mean deficit in the extensor muscle CSA was 14%. A larger deficit in knee extension power predicted slower stair-ascending and stair-descending times. This relationship remained unchanged when the power of the nonoperated side and the potential confounding factors were taken into account.

Limitations: The study sample consisted of people who were relatively healthy and mobile. Some participants had osteoarthritis in the nonoperated knee.

Conclusions: Deficits in muscle torque and power and in the extensor muscle CSA were present 10 months after knee replacement, potentially causing limitations in negotiating stairs. To prevent mobility limitations and disability, deficits in lower-limb power should be considered during rehabilitation after knee replacement.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?