Home > Journals > European Journal of Physical and Rehabilitation Medicine > Past Issues > Articles online first > European Journal of Physical and Rehabilitation Medicine 2022 Sep 01



Publishing options
To subscribe
Submit an article
Recommend to your librarian


Publication history
Cite this article as


Original Article   Open accessopen access

European Journal of Physical and Rehabilitation Medicine 2022 Sep 01

DOI: 10.23736/S1973-9087.22.07432-9

Copyright © 2022 THE AUTHOR(s)

This is an open access article distributed under the terms of the CC BY-NC 4.0 license which allows users to distribute, remix, adapt and build upon the manuscript, as long as this is not done for commercial purposes, the user gives appropriate credits to the original author(s) and the source (with a link to the formal publication through the relevant DOI), provides a link to the license and indicates if changes were made.

language: English

Reliability of point-of-care ultrasound for measuring quadriceps femoris muscle thickness

João PINTO-RAMOS 1, 2 , Cristina COSTA-SANTOS 2, 3, Frederico COSTA 1, Helena TAVARES 1, João CABRAL 1, Tiago MOREIRA 1, Rui BRITO 4, Joana BARROSO 1, 5, 6, 7, Bernardo SOUSA-PINTO 2, 3

1 Department of Physical Medicine and Rehabilitation, Centro Hospitalar Universitário São João, Porto, Portugal; 2 CINTESIS - Center for Health Technologies and Services Research, University of Porto, Porto, Portugal; 3 MEDCIDS - Department of Community Medicine, Information and Health Decision Sciences, Faculty of Medicine, University of Porto, Porto, Portugal; 4 Department of Physical Medicine and Rehabilitation, Centro Hospitalar do Porto, Porto, Portugal; 5 Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal; 6 i3s - Institute for Health Research and Innovation, University of Porto, Porto, Portugal; 7 Departments of Neuroscience and Physical Medicine and Rehabilitation, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA

BACKGROUND: Point-of-care ultrasound can be used to assess muscle thickness. However, its reliability has not been fully evaluated.
AIM: This study aims to assess the intra-rater and inter-rater reliability of point-of-care ultrasound for the estimation of quadriceps and rectus femoris thickness in patients from a rehabilitation setting.
DESIGN: Cross-sectional study.
SETTING: Physical Medicine and Rehabilitation Department of a tertiary care hospital.
POPULATION: Twenty-nine inpatients consecutively selected after admission.
METHODS: Four observers, two trained and two untrained, used point-of-care ultrasound to measure quadriceps femoris and rectus femoris thickness. Each observer performed two measurements followed by a second set of two measurements three hours later. Intraclass correlation coefficients (ICC) were then calculated.
RESULTS: Both intra-rater and inter-rater ICC were higher than 0.888 for both quadriceps and rectus femoris measurements. Reliability was highest when ICC were calculated based on the average of two measurements, with the intra-rater ICC being of 0.956 (95%CI=0.937-0.970) for rectus femoris and of 0.966 (95%CI=0.951-0.976) for quadriceps femoris, and with the inter-rater ICC being of 0.919 (95%CI=0.863-0.957) for rectus femoris and 0.945 (95%CI=0.907- 0.971) for quadriceps femoris. Trained and untrained observers did not have significantly different ICC values.
CONCLUSIONS: These results suggest that point-of-care ultrasound is a reliable option to measure muscle thickness of knee extensors by the same or different observers.
CLINICAL REHABILITATION IMPACT: Measuring knee extensors thickness may aid to adequately modulate treatment choices in patients with disability. This study suggests that quadriceps and rectus femoris muscle thickness measured after a short training course, by either an experienced or inexperienced clinician, presents high reliability. Reliability can be increased if the average of two measurements is used. Besides being inexpensive and portable, point-of-care ultrasound is a reliable tool for measuring knee extensors’ thickness, rendering it potentially adequate to be used in clinical practice.

KEY WORDS: Quadriceps muscle; Validation study; Ultrasonography

top of page