Real-time sonoelastography of the Achilles tendon: pattern description in healthy subjects and patients with surgically repaired complete ruptures

The purpose of this study is to describe the elastographic appearance of the Achilles tendon in healthy subjects and patients with surgically repaired complete ruptures. Nineteen Achilles tendons of 16 amateur footballers with surgically repaired complete ruptures and their contralateral asymptomatic Achilles tendons were assessed with ultrasound and real-time sonoelastography. Additionally, 40 asymptomatic Achilles tendons of 20 healthy amateur footballers were assessed. The Achilles tendons were divided into the distal, middle, and proximal thirds for elastographic image evaluation. Tendons were classified into three main types according to the elasticity features: type 1, blue (hardest tissue); type 2, blue/green (hard tissue); or type 3, green (intermediate tissue). In addition, three subtypes were determined: homogeneous, relatively homogeneous, and heterogeneous. Most of the Achilles tendons of the patients with surgically repaired complete ruptures were detected to have type 2 elasticity (64.9%), and the remaining had type 1 (35.1%). In contrast, most of the healthy tendons had type 2 (64.2%), and the remaining had either a type 3 (20.8%) or a type 1 (15%) elastographic pattern. All of the ruptured tendons had a heterogeneous structure, whereas all of the healthy Achilles tendons had a homogeneous or relatively homogeneous structure. In sonoelastography, the recognition of normal tendon structure will be useful in assessing pathologies of the Achilles tendon. Additionally, in patients with excellent American Orthopedic Foot and Ankle Society (AOFAS) scores and surgically repaired complete ruptures, a hard and heterogeneous pattern of tendon structure may be a natural consequence of tendon healing.