Stress Fractures in Ballet

Abstract

Stress fractures are common in young ballet dancers, however the roles of the individual contributing factors are unclear. The goal of this study was to review the etiopathophysiology of stress fractures (affected sites, predisposing factors, clinical identification, and diagnostic tests) with a consideration of lower kinetic chain biomechanics in a population of young females involved in intensive ballet training. A retrospective review of 1,023 medical charts from students enrolled at the National Ballet School, Toronto, Canada over the past 25 years was performed to identify the site, mechanism, and incidence of stress fracture. Stress fractures were reported in 31 (3%) cases. The second metatarsal, fibula, tibia, and lumbar spine were identified as areas vulnerable to stress fracture in this population, each associated with a characteristic biomechanical pattern of activity. In addition, 52% of all stress fractures documented were associated with other orthopaedic conditions such as hallux valgus, pronated feet, a longer second metatarsal, genu valgum, hyper-extension of the knees, and scoliosis. Young, skeletally immature females involved in intensive ballet training are especially susceptible to stress fracture development. A combination of repetitive loading and stressful lower kinetic chain activities, in addition to the influence of co-existing predisposing factors in this population, such as amenorrhea and decreased nutritional intake, all contribute to this condition. Evaluation of the unique repetitive movements inherent to this population will serve to direct preventative measures and provide appropriate rehabilitative strategies for stress fracture management.