Nakanowatari T1, Sasaki R1, Yamaguchi T1, Nagase T1, Kanzaki H1, Kiyoshige Y1
1Yamagata Prefectural University of Health Sciences, Physical Therapy, Yamagata, Japan
Background: Shortening of the tensor fasciae latae is related with functional leg length discrepancy (LLD) after total hip arthroplasty. However, no studies have investigated the effects of functional LLD on the tensor fasciae latae stiffness. Therefore, we created artificial functional LLD and assessed tensor fasciae latae stiffness using ultrasound shear wave elastography in healthy individuals. In addition, it has been reported that shoe lift can improve functional LLD. Thus, shoe lift could improve the stiffness reduction caused by artificial functional LLD.
Purpose: The study aimed to investigate the effects of artificial functional LLD on the tensor fasciae latae stiffness during a standing using ultrasound shear wave elastography and whether shoe life improves the stiffness reduction caused by artificial functional LLD.
Methods: Twelve healthy young men (age 21.8) participated in this study. To mimic functional LLD, their right leg was fixed in 20 degrees of hip abduction with a hip brace. The participants were instructed to put both foot on the floor during a standing. The height of the shoe lift was individually adjusted to correct their flexing right knee resulted from the functional LLD. The shoe lift put under the left foot. The participants were performed in three different conditions:
(1) with a hip brace, but unrestricted (control),
(2) with a hip brace (functional LLD condition), and
(3) with both hip brace and shoe lift (shoe lift condition).
We measured the shear elastic modulus of the right tensor fasciae latae as a stiffness index using ultrasound shear wave elastography. The measurement site was defined as the mid-point between the anterior superior iliac spine and the greater trochanter of the femur. One-way repeated measures ANOVA was used to determine the effects of standing condition on the stiffness. Tukey's HSD post hoc test was performed to compare the conditions. A significance level of 0.05 was used.
Results: A significant main effect was observed on the standing conditions (p 0.01). The tensor fasciae latae stiffness was significantly lowered in the functional LLD condition (19.3 ± 4.4 kPa) compared to both shoe lift condition (26.9 ± 9.6 kPa, p 0.05) and control condition (29.1 ± 6.5 kPa, p 0.01), while no difference between shoe lift condition and control condition.
Conclusion(s): Our results suggest that artificial functional LLD reduces the tensor fasciae latae stiffness in healthy individual. On the other hand, shoe lift can improve the stiffness reduction. Further studies are needed to investigate whether our findings are applicable to elderly and female people with total hip arthroplasty.
Implications: The study provide information that the standing with functional LLD may causes the shortening of the tensor fasciae latae. Shoe lift can maintain the appropriate length of the tensor fasciae latae during standing and help to improve functional LLD.
Keywords: Functional Leg Length Discrepancy, Tensor Fasciae Latae, Ultrasoud Shear Wave Elastography
Funding acknowledgements: This study was supported by JSPS KAKENHI grant number 18K17755 and a research grant from Yamagata health support association.
Purpose: The study aimed to investigate the effects of artificial functional LLD on the tensor fasciae latae stiffness during a standing using ultrasound shear wave elastography and whether shoe life improves the stiffness reduction caused by artificial functional LLD.
Methods: Twelve healthy young men (age 21.8) participated in this study. To mimic functional LLD, their right leg was fixed in 20 degrees of hip abduction with a hip brace. The participants were instructed to put both foot on the floor during a standing. The height of the shoe lift was individually adjusted to correct their flexing right knee resulted from the functional LLD. The shoe lift put under the left foot. The participants were performed in three different conditions:
(1) with a hip brace, but unrestricted (control),
(2) with a hip brace (functional LLD condition), and
(3) with both hip brace and shoe lift (shoe lift condition).
We measured the shear elastic modulus of the right tensor fasciae latae as a stiffness index using ultrasound shear wave elastography. The measurement site was defined as the mid-point between the anterior superior iliac spine and the greater trochanter of the femur. One-way repeated measures ANOVA was used to determine the effects of standing condition on the stiffness. Tukey's HSD post hoc test was performed to compare the conditions. A significance level of 0.05 was used.
Results: A significant main effect was observed on the standing conditions (p 0.01). The tensor fasciae latae stiffness was significantly lowered in the functional LLD condition (19.3 ± 4.4 kPa) compared to both shoe lift condition (26.9 ± 9.6 kPa, p 0.05) and control condition (29.1 ± 6.5 kPa, p 0.01), while no difference between shoe lift condition and control condition.
Conclusion(s): Our results suggest that artificial functional LLD reduces the tensor fasciae latae stiffness in healthy individual. On the other hand, shoe lift can improve the stiffness reduction. Further studies are needed to investigate whether our findings are applicable to elderly and female people with total hip arthroplasty.
Implications: The study provide information that the standing with functional LLD may causes the shortening of the tensor fasciae latae. Shoe lift can maintain the appropriate length of the tensor fasciae latae during standing and help to improve functional LLD.
Keywords: Functional Leg Length Discrepancy, Tensor Fasciae Latae, Ultrasoud Shear Wave Elastography
Funding acknowledgements: This study was supported by JSPS KAKENHI grant number 18K17755 and a research grant from Yamagata health support association.
Topic: Musculoskeletal: lower limb; Orthopaedics
Ethics approval required: Yes
Institution: Yamagata Prefectural University of Health Sciences
Ethics committee: Research ethics committee
Ethics number: 1806-08
All authors, affiliations and abstracts have been published as submitted.
