Estudo ultrassonográfico do tendão de Aquiles de bailarinos assintomáticos: explorando as relações entre estrutura e medidas clínicas

Abstract

The central theme of this thesis is the study of structural changes in the Achilles tendon in classical ballet dancers. When a tendon is subjected to mechanical loads, it can respond positively (adaptation) or negatively, leading to tendon pathologies. These pathologies are structural changes observed via ultrasonography, characterized by tendon thickening and the presence of focal areas of low echogenicity, indicating collagen fibre disorganization. Tendon pathologies are found in individuals with tendinopathy and asymptomatic individuals. In the latter case, these individuals have a sevenfold increased risk of developing tendon pain. Classical ballet dancers belong to this group, exhibiting high frequencies of tendon pathologies. Modifiable clinical factors, such as plantar flexor strength, dorsiflexion range of motion, and subtalar pronation, are related to the occurrence of Achilles tendinopathy. However, the relationship between these measures and the presence of tendon pathologies in asymptomatic individuals is unclear. Thus, early identification of these pathologies, before symptom development, may offer an additional prevention opportunity. It is also known that the practice of dance places high loads on the Achilles tendon, but the long-term effect of this overload on the development of tendon symptoms is not well understood. Besides Achilles tendon impairments, the ankle joint is the region with the highest incidence of injury in dancers. Therefore, other structures in this region may be overloaded, resulting in posterior ankle pain, a common clinical presentation among various ankle conditions. Correct identification of the pain source is essential for effective therapeutic approaches and good prognoses. Based on the above, this thesis aimed to address some of the gaps presented. Study 1 was a cross-sectional study aimed at investigating the predictive value of clinical measures commonly associated with Achilles tendinopathy in identifying tendon pathologies in asymptomatic dancers. Study 2, using a longitudinal design, explored the structural response of the Achilles tendon, using Ultrasound Tissue Characterization (UTC), during the rehearsal and performance season of the repertoire ballet "Swan Lake." We also investigated clinical outcomes after 4 months as symptoms in the posterior ankle region through a comprehensive and differential clinical evaluation. The results from study 1 highlighted the importance of hip strength in Achilles tendon structure and indicated that interactions between hip torque and ankle dorsiflexion were associated with the presence of tendon pathology. In study 2, findings showed that the rehearsal and performance period did not adversely affect the Achilles tendon structure, and in the long term, few dancers developed clinical signs of tendinopathy when using the assessment tool presented in the study. This thesis provides new insights that can be implemented in clinical practice and incorporated into research methodologies.