Objectives: The purpose of our paper was to evaluate by sonoelastography the Achilles tendon of asymptomatic volunteers and of patients referring for chronic overuse-associated pain, also comparing these findings with those obtained with B-mode ultrasound (US).
Methods: This study had local Ethics Committee approval; all patients gave their written informed consent. Twelve patients (9 men, 3 women, median age 52.5 years, range 38-64 years) referred for unilateral Achilles tendon pain associated with amateur sporting activities and 18 healthy controls (11 men, 7 women, median age 54 years, range 27-64 years) were studied. US/sonoelastography were performed with a Logos EUB8500 system (Hitachi Ltd., Tokyo, Japan) equipped with a 10-6 MHz high-resolution broadband linear array, on 12 symptomatic tendons and 36 controls. The probe was positioned at the calcaneal enthesis, retrocalcaneal bursa, myotendineus juction, and in three different areas of the tendon body. The elastogram colour range was translated to a numeric score and the differences of tendon resilience were compared by the Kruskall-Wallis test.
Results: On US, symptomatic tendons showed increased tendon thickness (12/12 tendons vs. 8/36 controls, p<0.0001), interruption (5/12 vs. 0/36, p=0.0004), and fragmentation (5/12 vs. 0/36, p=0.0004). Disappearance of fibrillar echotexture was comparable in the two groups. Symptomatic tendons were harder, showing a prevalence of blue to green colour (p<0.0001). Loss of elasticity was associated with both fragmentation (p=0.0089) and loss of fibrillar texture (p=0.0019), and was inversely correlated with tendon thickness (p<0.0001). Sonoelastography showed no difference between symptomatic and control tendons at the enthesis and myotendineus junction.
Conclusions: Sonoelastography shows increased stiffness in symptomatic enlarged Achilles tendons in comparison to normal ones.