Loss of knee-extension strength is related to knee swelling after total knee arthroplasty

TY - JOUR

T1 - Loss of knee-extension strength is related to knee swelling after total knee arthroplasty

AU - Holm, Bente

AU - Kristensen, Morten T

AU - Bencke, Jesper

AU - Husted, Henrik

AU - Kehlet, Henrik

AU - Bandholm, Thomas

N1 - Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

PY - 2010/11/1

Y1 - 2010/11/1

N2 - Objective To examine whether changes in knee-extension strength and functional performance are related to knee swelling after total knee arthroplasty (TKA). Design Prospective, descriptive, hypothesis-generating study. Setting A fast-track orthopedic arthroplasty unit at a university hospital. Participants Patients (N=24; mean age, 66y; 13 women) scheduled for primary unilateral TKA were investigated 1 week before surgery and on the day of hospital discharge 2.4 days postsurgery. Interventions Not applicable. Main Outcome Measures We assessed all patients for knee-joint circumference, knee-extension strength, and functional performance using the Timed Up & Go, 30-second Chair Stand, and 10-m fast speed walking tests, together with knee pain during all active test procedures. Results All investigated variables changed significantly from pre- to postsurgery independent of knee pain. Importantly, knee circumference increased (knee swelling) and correlated significantly with the decrease in knee-extension strength (r=-.51; P=.01). Reduced fast-speed walking correlated significantly with decreased knee-extension strength (r=.59; P=.003) and decreased knee flexion (r=.52; P=.011). Multiple linear regression showed that knee swelling (P=.023), adjusted for age and sex, could explain 27% of the decrease in knee-extension strength. Another model showed that changes in knee-extension strength (P=.009) and knee flexion (P=.018) were associated independently with decreased performance in fast-speed walking, explaining 57% of the variation in fast-speed walking. Conclusions Our results indicate that the well-known finding of decreased knee-extension strength, which decreases functional performance shortly after TKA, is caused in part by postoperative knee swelling. Future studies may look at specific interventions aimed at decreasing knee swelling postsurgery to preserve knee-extension strength and facilitate physical rehabilitation after TKA.

AB - Objective To examine whether changes in knee-extension strength and functional performance are related to knee swelling after total knee arthroplasty (TKA). Design Prospective, descriptive, hypothesis-generating study. Setting A fast-track orthopedic arthroplasty unit at a university hospital. Participants Patients (N=24; mean age, 66y; 13 women) scheduled for primary unilateral TKA were investigated 1 week before surgery and on the day of hospital discharge 2.4 days postsurgery. Interventions Not applicable. Main Outcome Measures We assessed all patients for knee-joint circumference, knee-extension strength, and functional performance using the Timed Up & Go, 30-second Chair Stand, and 10-m fast speed walking tests, together with knee pain during all active test procedures. Results All investigated variables changed significantly from pre- to postsurgery independent of knee pain. Importantly, knee circumference increased (knee swelling) and correlated significantly with the decrease in knee-extension strength (r=-.51; P=.01). Reduced fast-speed walking correlated significantly with decreased knee-extension strength (r=.59; P=.003) and decreased knee flexion (r=.52; P=.011). Multiple linear regression showed that knee swelling (P=.023), adjusted for age and sex, could explain 27% of the decrease in knee-extension strength. Another model showed that changes in knee-extension strength (P=.009) and knee flexion (P=.018) were associated independently with decreased performance in fast-speed walking, explaining 57% of the variation in fast-speed walking. Conclusions Our results indicate that the well-known finding of decreased knee-extension strength, which decreases functional performance shortly after TKA, is caused in part by postoperative knee swelling. Future studies may look at specific interventions aimed at decreasing knee swelling postsurgery to preserve knee-extension strength and facilitate physical rehabilitation after TKA.

U2 - 10.1016/j.apmr.2010.07.229

DO - 10.1016/j.apmr.2010.07.229

M3 - Journal article

SN - 0003-9993

VL - 91

SP - 1770

EP - 1776

JO - Archives of Physical Medicine and Rehabilitation

JF - Archives of Physical Medicine and Rehabilitation

IS - 11

ER -