Ruptured and Intact Achilles Tendons: Importance of Sonoelastography and Introduction of Novel Assessment Tools

Purpose: The concept of assessing the mechanical properties of the Achilles tendon after reconstruction using ultrasound shear wave elastography (SWE) was recently introduced into clinical practice. Because it was demonstrated that ∼ 6% of patients with ruptured Achilles tendon will experience the rupture of the contralateral tendon in the future, we aimed to estimate the risk for rupture of the contralateral tendon in patients who underwent surgical reconstruction of ruptured Achilles tendon by using a standardized subjective questionnaire and ultrasound SWE. Additionally, we proposed a novel questionnaire for assessment of healthy individuals and patients after Achilles tendon surgical reconstruction. Validation of the questionnaire was conducted by evaluation whether the final score had a relationship with values obtained with SWE. SWE morphograms were analyzed with newly designed software that has the ability to quantify the whole elastogram area.

Methods and Materials: Twenty-four patients who underwent surgical repair of the ruptured Achilles tendon and 12 aged-matched healthy controls were examined with ultrasound SWE, and elastograms were analyzed using the proposed new software. Functional outcomes were assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) scoring system and a subjective rating system that we introduced and validated. A novel questionnaire was composed of nine questions relying on the widely used Achilles Tendon Total Rupture Score and AOFAS scoring system regarding assessment of capabilities and subjective feelings after Achilles tendon reconstruction. A total of 20 internationally recognized musculoskeletal radiologists (5), orthopaedic surgeons (10), and physiatrists (5) were invited to participate in the questionnaire validation. Final multiple-choice questions were developed by the researchers based on the domains that were answered as “very important” by ≥ 70% of first- and second-round survey respondents.

Results: The stiffness of the injured tendon was markedly decreased (by 42%) compared with the contralateral tendon of the same patient. Both AOFAS score and our novel subjective assessment scale positively correlated with ultrasound SWE values in ruptured Achilles tendons. The stiffness of contralateral Achilles tendons in patients was 23% lower than among healthy individuals.

Conclusion: Irrespective of the lack of difference in the subjective feeling assessed by AOFAS and proposed novel subjective questionnaire, the contralateral tendon in the patients with reconstructed Achilles tendon had a significantly lower stiffness than healthy individuals. Therefore, contralateral tendons in patients who experienced a rupture are more prone to future ruptures.