Poetry of Motion: Ankle Biomechanics in Ballet Dance

Category: Sports; Ankle Introduction/Purpose: Ankle sprains are one of the most common acute injuries amongst ballet dancers and may lead to chronic ankle instability. Certain ballet positions, if performed incorrectly or with inadequate technique, can further increase the risk of bone and soft tissue injuries. Dancing en pointe, which forces the foot and ankle into extreme plantar flexion, has been reported as the most common mechanism of injury. While these injuries occur frequently, little research has been done to understand the biomechanics of the foot and ankle in ballet. The aim of this study was to use weightbearing computed tomography (WBCT) and distance mapping to describe ankle joint mechanics in various ballet positions. Methods: This was an institutional review board approved case study analyzing five healthy professional ballerinas. WBCT scans were taken bilaterally in five different positions: a control/neutral position, first position, fifth position, plié, and relevé (en pointe). A semi-automatic software was used to segment models of all bones proximal to the first distal phalanx. Talar dome and gutter articulations were selected manually, and distances along the entire tibiofibular interface and gutter articulations were calculated using a previously published protocol. The mean syndesmosis width was calculated at 1 cm, 3 cm, and 5 cm from the tibiotalar joint. Results: Syndesmotic widening was greatest in first position at 5 cm above the tibiotalar joint (Mean: 9.39 mm). The relevé position consistently had the greatest syndesmotic narrowing at all heights along the syndesmosis. The anteromedial gutter had the largest range in regard to distance mapping, with greatest joint space width in fifth position (Mean: 4.99 mm) and narrowest joint space in plié (Mean: 2.68 mm). More specifically, in fifth position the anteromedial gutter space was 71% wider than the control position. Conclusion: This study is the first of its kind to mechanistically describe the ankle as it relates to ballet dancing. Interestingly, syndesmotic and tibiotalar joint space widening was greatest in first and fifth position, which may suggest that external rotation plays a greater contributing role in ankle instability compared to plantarflexion in ballet. Future research with larger cohorts and more WBCT stress positions is needed to comprehensively understand the foot and ankle joint mechanics in this demanding sport.