Sonoelastographıc assessment of the age-related changes of the Achilles tendon

Tendons are crucial for optimal muscle force transfer and subject to changes with aging which may impair functional ability of elderly individuals. Achilles is the largest and the strongest tendon in the body; therefore it is an excellent site for the radiologic investigation of aging of tendons. Sonoelastography (SE) is a new ultrasound-based imaging technique that provides information on elastic properties and stiffness of tissues. The aim of our study was to investigate the age-related alterations in Achilles tendons using SE.

Forty five geriatric (age ≥ 65 years) and 42 young (age 18-40 years) healthy consecutive subjects were enrolled. Subjects with known history of metabolic or endocrine diseases, sports or traumatic injuries, peripheral vascular disorders were excluded. Both Achilles tendons were scanned with a real-time SE probe at a frequency of 6-15 MHz. Strains of Achilles tendons' proximal, middle and distal parts were assessed semi-quantitatively with comparing a reference tissue.

Both SE methods -color coded evaluation and strain measurement- showed a remarkably stiffer tendon in the elderly subjects compared to young subjects in all thirds of Achilles tendons. In young subjects 84.9 % tendon thirds were blue, and 15.1% were green whereas, in elders 93.7% were blue and 6.3% were green (p=0.024). There was a significant correlation between age and stiffness of tendons assessed with strain indices.

Our result showed increased tendon stiffness in elderly subjects which might be responsible for the high prevalence of Achilles tendinopathies observed in elderly subjects.