Summary

Bilateral foot and ankle MRIs of 31 professional ballet dancers were reviewed and a high prevalence of bone marrow oedema in the talus and the metatarsals were found.

Abstract

Background

The use of Magnetic Resonance Imaging (MRI) is considered the gold standard assessment tool for the most common injuries that are sustained in the elite ballet foot and ankle, namely, posterior ankle impingement, ligament injury, bone stress reaction and tendon injury. However, it is sometimes difficult to evaluate the foot and ankle MRIs in dancers since some of the signal changes seen on MRI scans are secondary to the repetitive high loads to which dancers are exposed during training and they may not be pathological or in any way related to an injury. Previous studies have investigated MRI findings of ballet dancers’ ankles, but they lack information on forefoot and tendon pathologies other than flexor hallucis longus tendon. Therefore, the present study aims to fully identify asymptomatic radiological findings in the feet and ankles of ballet dancers.

Methods

Thirty-one professional ballet dancers (15 men and 16 women; mean age, 26.5 ± 4.3 years) who were dancing in full capacity were included in this prospective study. Dancers who had foot or ankle pain requiring modification of dance activities which lasted for more than one week or had a history of surgery, fracture or bone stress reaction to the foot or ankle in the last six months were excluded. Orthogonal 3-plane STIR imaging of both feet and ankles was obtained using 3.0-T MRI and the images were reviewed using a standardised evaluation form by two musculoskeletal radiologists.

Results

Fifty (80.6%) of the 62 feet and ankles had at least one bone marrow oedema. The common locations of bone marrow oedema were talus (n = 39, 62.9%), metatarsals (n = 17, 27.4%), and tarsal bones (n = 10, 16.1%). Os trigonum and Stieda process were seen in 5 (8.1%) and 8 (12.9%) ankles respectively and among them, bone marrow oedema was seen in two os trigonum. In addition, posterior synovitis was seen in 11 ankles (17.7%). Ligament pathologies were found in the anterior talofibular ligament in 8 ankles (12.9%) and deltoid ligaments in 4 ankles (6.5%). Fluid around flexor hallucis longus, posterior tibialis and peroneal tendons were observed in 13 (21.0%), 8 (12.9%) and 6 (9.7%) ankles respectively. The increased signal intensity of tendons was seen in the Achilles tendon in 6 ankles (9.7%) and the peroneal tendon in one ankle (1.6%).

Conclusion

This study showed the prevalence of foot and ankle MRI findings in asymptomatic professional ballet dancers. Those findings may come from high loads to which dancers are exposed and may not be related to symptoms. The results of this study would help interpret the MRI findings in symptomatic ballet dancers. Further analysis investigating the relationship between the MRI findings and the past and future injuries is warranted.