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· DOS Abstracts
Validity and Reliability of an Ultrasound Measurement
of the free length of the Achilles tendon.
Kristoffer W. Barfod, Anja Falk Riecke, Anders Boesen, Philip Hansen, Jens Fried-
rich Maier, Simon Doessing, Anders Troelsen
Department of Orthopedics, Clinical Orthopedic Research Hvidovre, Copenha-
gen University Hospital Hvidovre, Denmark.
Background:
Valid length measurements of the different segments of the
Achilles tendon, that connect to the three muscle bellies of the triceps surae are
needed in order to investigate if differential elongation of the Achilles tendon
takes place after rupture.
Purpose / Aim of Study:
The purpose of this paper is to present data con-
cerning accuracy and reliability of an ultrasound measurement of the free part
of the Achilles tendon.
Materials and Methods:
Both legs of 19 non-injured subjects were examined
by MRI and ultrasound. The length from the distal tip of the soleus muscle to the
tendon insertion on calcaneus was measured by three independent ultrasound
examiners. Repeated ultrasound measurements were performed and compared
to MRI measurements. Intra-rater and inter-rater reliability and the agreement
between MRI and ultrasound were determined. Data were evaluated using the
Intraclass Correlation Coefficient (ICC), the Standard Error of the Measurement
(SEM) and the Minimal Detectable Change (MDC).
Findings / Results:
The measurement showed excellent intra-rater reliability
(ICC 0.94 [0.91;0.96], SEM 5mm and MDC 13mm) and inter-rater reliability
(ICC 0.96 [0.93;0.97], SEM 4mm and MDC 11mm). Ultrasound measurements
on average exceeded the MRI measurements by 2mm (n.s.); resulting in a mea-
surement error of 5%.
Conclusions:
The ultrasound measurement of the free part of the Achilles ten-
don showed good reliability and accuracy. For comparison between groups of
non-injured subjects differences of more than 5mm can be detected. For re-
peated assessment of individual subject differences ≥ 13mm can be detected.
The US measurement is a promising clinical tool to be further assessed in the
setting of acute Achilles tendon rupture.
No conflicts of interest reported
56.