Functional Ultrasound Elastography (FUSE) of Tendo Achilles is an ultrasound technique utilising controlled, measurable movement of the foot to non-invasively evaluate TA elastic and load-deformation properties. The study purpose is to assess Achilles tendons, paratenon and bursa mechanical properties in healthy volunteers and establish a clinical outcome tool for TA treatment.

We studied 40 Achilles tendons in healthy volunteers using our novel Elastography method, which we developed in the University of Oxford. US scan device (Z.one, Zonare Medical System Inc., USA, 8.5 MHz) with and without the Oxford isometric dynamic foot and ankle mover were used. Tendon insertion, midportion and musculotendinous junction were examined during lateral movement and axial compression/decompression modes. B mode and elasticity images were derived from the raw ultrasound radio frequency data. The anatomical structures mechanical properties were evaluated by a semi-quantitative score of different colours representing stiff tissue (blue) to more soft tissue (green, yellow, red).

The Achilles tendons showed mainly a hard structured pattern on sonoelastography. Compression/decompression modes are best used to demonstrate axial softening, while longitudinal displacement is best used to assess load transfer. The average strain along the tendon was 2% (range 0-6%). The overall correlation (?) between real-time sonoelastography and ultrasound findings was < 0.3. However, the correlation (?) between FUSE UEI and US findings was 1.0

Our findings show that FUSE seems to be a sensitive method for assessment of TA mechanical properties. The B mode and elasticity images must be viewed simultaneously. Elasticity and stiffness measurement may offer an invaluable tool to guide TA rupture and tendonopathy treatment and rehabilitation protocol.