Anterior and Posterior Dynamic Hip Ultrasonography Measures of Femoroacetabular Translation in Professional Ballet Dancers

OBJECTIVES: To determine population values of femoroacetabular translation using dynamic hip ultrasonography (DHUS) in professional ballet dancers. DESIGN: Cross-sectional cohort. SETTING: Three ballet companies. PARTICIPANTS: Ninety professional ballet dancers. INTERVENTIONS: Dynamic hip ultrasonography was performed (12 images/dancer, 1080 images). Biometrics included Trochanteric Prominence Angle Test and Beighton Score. MAIN OUTCOME MEASURES: Anterior and posterior DHUS measures were documented, and femoroacetabular translation was calculated. RESULTS: Anterior exam mean values for female dancers in neutral (N), neutral flexed (NF), and extension external rotation (EER) positions were 4.3 ± 2.05, 9.4 ± 2.61, and 11.4 ± 2.83, respectively, and anterior translation 2.1 ± 2.08; for posterior exam, posterior neutral, posterior flexion adduction internal rotation, and posterior stand positions showed a median value (interquartile range [IQR]) 0 (0-2) and mean values of 11.7 ± 4.89 and 8.8 ± 4.63, respectively, and posterior femoroacetabular translation 10.4 ± 4.62. Ultrasound measures for male dancers' anterior exam showed 5.5 ± 2.86, 10.9 ± 2.82, and 12.9 ± 2.78 and anterior translation 1.9 ± 1.62, and posterior exam measures showed median (IQR) 0 (0-3) and mean 11.3 ± 4.69 and 10.1 ± 5.36 and posterior femoroacetabular translation 9.6 ± 3.82. Differences by sex were found in N and NF positions: male dancers had greater translation versus female dancers in the left ( P = 0.03 and P = 0.03, respectively) and right hips ( P = 0.02 and P = 0.004, respectively). Males had greater EER in the right hip compared with females ( P < 0.001). CONCLUSIONS: Dynamic hip ultrasonography determined population values in professional ballet dancers. Sex-based differences among dancers were found.