Hip Translational Motion Measured By Dynamic Ultrasound In Collegiate Ice Hockey Athletes

PURPOSE:There is a need to better understand hip translational motion and pathologic microinstability in the athletes. Dynamic ultrasound (DUS), used to measure femoroacetabular translation, can further our understanding of this challenging clinical entity. We aimed to establish DUS measures of femoroacetabular translation in a cohort of collegiate ice hockey athletes and to investigate associations with femoral morphology (version) and joint laxity. METHODS:A cross-sectional cohort study of DUS measures in healthy collegiate ice hockey athletes was employed. DUS measures for the anterior hip included neutral (N), neutral flexed (NF), extension external rotation (EER) (d’Hemecourt et al, CORR 2019), and for the posterior hip, posterior neutral (PN), posterior flexion-adduction-internal rotation (PFADIR), and stand-and-load (PStand) (Le et al, Skel Radiol 2024). Biometric measures included femoral version (Trochanteric Prominence Angle Test (TPAT)) and joint laxity (9-point Beighton). Statistical analyses included independent t-tests, one-way ANOVA and Wilcoxon rank-sum tests for non-normally distributed variables. Multivariate regression models were adjusted for age, sex, and BMI to determine independent predictors of femoroacetabular translation. RESULTS:The cohort included 26 athletes, 61.5% male, median age 21.2 years (IQR: 21-22). The median DUS anterior and posterior measures (mm, Q1,Q3) were N 4.8 (3-6.3), NF 9.7 (8.1-10.7), EER 9.6 (7.1-11.9), anterior translation 0.1 (-1.0-1.4), PN 1.3 (0.3-3), PFADIR 11.2 (8.9-12.5), PStand 7.2 (5-10.1), and posterior translation 8.8 (7.3-11.3). Most ice hockey athletes showed normal femoral version and Beighton scores ≤4 (80%, 88% respectively). DUS measures by sex found that male athletes exhibited greater anterior hip translation in the EER position vs. female athletes (10.4 v. 7.2 mm; P = 0.008), and posterior translation in the PFADIR (10.9 v. 9.7 mm; P = 0.011) and PStand (8.5 v. 5.0 mm; P = 0.011) positions vs. female athletes. An association was found between Beighton score and anterior hip translation in the neutral position (r = 0.45, p = 0.024). CONCLUSION:DUS measures of hip translational micro motion are presented in a small cohort of collegiate ice hockey athletes. Joint laxity and sex may contribute to hip translational motion.