Prevalence of Asymptomatic Bone Marrow Edema in the Talus in Professional Ballet Dancers: Preliminary Data from 2-Year Prospective Study

CATEGORY: Ankle; Sports INTRODUCTION/PURPOSE: Bone marrow edema (BME) appears as increased interstitial fluid accumulation within the bone marrow on magnetic resonance images (MRI). Asymptomatic BME has been found incidentally and described in competitive athletes, long- distance runners, and patients with altered biomechanics where the true etiology remains unclear. The natural history and clinical implications of asymptomatic BME in the elite and actively-competing athlete is not well characterized. Moreover, there is debate on how to manage and counsel patients on these findings in a high-risk bone such as the talus. This study presents early data from a prospective enrollment study of professional ballet dancers characterizing the prevalence of asymptomatic BME in the talus. METHODS: Fourteen (14) professional ballet dancers enrolled in the 2-year prospective, IRB-approved study after informed consent was obtained. Exclusion criteria included: subjects reporting foot and ankle pain or disability on initial preseason evaluation, foot and ankle surgery or injury within the last year prior to evaluation, and any contraindications for MRI. Subjects underwent a physical examination and completed Foot and Ankle Ability Measure (FAAM) and Foot and Ankle Disability Index scores (FADI). Bilateral foot and ankle MRIs without contrast were completed upon study enrollment and interpreted by a blinded, fellowship-trained musculoskeletal radiologist. RESULTS: Of 14 professional ballet dancers enrolled in the study, 6 were female, 8 were male, and the mean age was 24.4 years. All dancers reported no pain or disability in their feet and ankles at the time of evaluation and had physical exam findings unremarkable for performance-limiting pathology. Of the 14 dancers, 64% (9) had MRI evidence of talar BME. 6 subjects had bilateral talar BME and 3 had unilateral findings. 53% (8) had BME localized to the posterior process of the talus, 13% (2) localized in the talar body, 13% (2) localized to the talar head and neck, and 20% (3) subjects had pan-talar BME. All subjects had BME seen only on T2 sequences with one patient demonstrating bilateral pan-talar BME on both T1 and T2 sequences. There was no significant correlation using Welch’s unequal variances t-test (α = 0.05) between talar BME and either FADI or FAAM scores. CONCLUSION: These findings demonstrate a high prevalence (64%) of talar bone marrow edema in asymptomatic professional ballet dancers with benign physical exams and normal functional scores. Yet, the long-term clinical significance of these findings are unknown.