The Vienna morphological Achilles tendon score-VIMATS : Description, reproducibility and initial clinical results

Abstract

Objective: The purpose was to introduce the Vienna morphological Achilles tendon score (VIMATS), to evaluate its reproducibility and to assess its clinical application.

Methods: In 38 patients a total number of 40 painful ATs and 20 volunteers were examined on a 3T magnetic resonance imaging (MRI) scanner using a standard MRI protocol. In 20 patients clinical scoring according to the Achilles tendon rupture score was available. Two observers independently assessed the thickness, continuity, signal intensity, and associated pathologies of the Achilles tendon (AT) according to the newly created VIMATS. Intraobserver and interobserver agreements were calculated and the clinical application of the VIMATS regarding its potential to differentiate between patients and volunteers was tested.

Results: An analysis of the Intraclass correlation coefficient (ICC) yielded an excellent intraobserver (ICC 0.925) and interobserver agreement (ICC 0.946) for the total VIMAT score. A significant difference in total VIMATS was found between patients (47.6 ± StD 21.1 points) and volunteers (91.5 ± SD 10.9 points; p < 0.01) as well as a moderate correlation between morphological and clinical scoring (Pearson correlation 0.644).

Conclusion: The VIMAT score is the first MRI score for the semiquantitative morphological evaluation of AT injuries and was shown to be an easy, fast and reproducible tool for assessing injuries of the AT.

Keywords: Achilles tendon; Magnetic resonance imaging; Radiological assessment; Scoring; Tendinopathy.

Fig. 1

Correct measurement of the Achilles tendon thickness—measured distance from the anterior to the posterior margin of the tendon

Fig. 2

Case example of a 51-year-old female patient with pain in the AT for 2 months. The maximum thickness of the AT from anterior to posterior, perpendicular to the coronal axis of the AT, on the axial T2‑w image (a; double-headed arrow), was 9.7 mm (20 points). Furthermore, the patient presented with a partial tear (10 points) and fluid-like signal intensity (0 points; long arrow) on the sagittal PD‑w TSE image (b). Associated pathologies (20 points): no Haglund exostosis (minus 0 points; parallel lines (c)), no calcaneal bone marrow edema or cysts (b) but an ossification at the tendon insertion area (–5 points; star) on the T1‑m sagittal image (c); no edema of Kager’s fat pad but slight signal increase along the AT indicating a peritendinitis (b) (–5 points; small arrows); positive retrocalcaneal bursitis (b) (–5 points; curved arrow). Total VIMAT score = 35 points

Fig. 3

Correlation between clinical scoring according to the Achilles tendon rupture score and the total score of the Vienna morphological Achilles tendon score (0.644) - X Axis: VIMATS points, Y axis: interquartile