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Ultrasound of the coracoacromial ligament in asymptomatic volunteers and patients with shoulder impingement

Tobias J Dietrich, Maciej Jonczy, Florian M Buck, Reto Sutter, Gabor Puskas & Christian Wa Pfirrmann

abstract

BACKGROUND
The coracoacromial ligament is part of the coracoacromial arch, which is considered to be involved in shoulder impingement.

PURPOSE
To compare the coracoacromial ligament on ultrasound in asymptomatic volunteers and in patients with subacromial shoulder impingement.

MATERIAL AND METHODS
Twenty-nine asymptomatic volunteers (mean age, 35.5 years) and 29 patients (mean age, 49.9 years) with shoulder impingement, diagnosed by experienced shoulder surgeons, were prospectively included. Two radiologists obtained and analyzed ultrasound images of the coracoacromial ligament in the longitudinal axis.

RESULTS
The ligament thickness was 1.4 ± 0.2 mm at its midportion, 1.8 ± 0.4 mm at the coracoid, and 2.1 ± 0.6 mm at the acromion in asymptomatic volunteers compared with 1.3 ± 0.2 mm, 1.9 ± 0.5 mm, and 1.9 ± 0.5 mm in impingement patients for observer 1. The ligament length was 30.6 ± 2.4 mm in asymptomatic volunteers compared with 30.4 ± 3.6 mm in impingement patients for observer 1. An anteriorly convex shape of the superficial contour of the coracoacromial ligament was significantly more frequent in impingement patients compared with asymptomatic volunteers for both observers (observer 1: 10% (3/29) versus 45% (13/29), P value <0.01; observer 2: 10% (3/29) versus 38% (11/29), P value <0.03). The comparison of the remaining parameters of the coracoacromial ligament, such as the thickness, length, echogenicity, and fibrillation did not reveal significant differences between volunteers and patients.

CONCLUSION
While thickness or length of the coracoacromial ligament were similar in volunteers and patients with shoulder impingement, an anteriorly convex shape of the superficial contour of the coracoacromial ligament was significantly more frequent in impingement patients compared with asymptomatic volunteers.
   
citation Dietrich T J, Jonczy M, Buck F M, Sutter R, Puskas G, Pfirrmann C W. Ultrasound of the coracoacromial ligament in asymptomatic volunteers and patients with shoulder impingement. Acta Radiol 2016; 57:971-977.
   
type journal paper/review (English)
date of publishing 1-8-2016
journal title Acta Radiol (57)
ISSN electronic 1600-0455
pages 971-977
PubMed 26508794
DOI 10.1177/0284185115610930
contact Gabor Puskas