Shearwave Elastography in the Evaluation of Iliotibial Band Syndrome

Overview

Iliotibial band syndrome (ITBS) is a condition frequently treated in physiotherapy. The pathophysiology underlying this syndrome is still poorly understood. Ultrasound makes it possible to evaluate the morphology and to quantify, with sonoelastography (SWE), the stiffness of the iliotibial band (ITB). The objective is to determine the feasibility of a cross-sectional study aimed at evaluating the morphometry and stiffness of the ITB in runners with and without a diagnosis of ITBS. Socio-demographic and clinical data will be collected and ultrasound measurements (thickness and stiffness) of the iliotibial band will be performed in supine with the knee positioned at 2 different angles (0° and 30° flexion). Variables such as the recruitment rate/month, the inclusion/exclusion rate, the acceptability of the procedure will be used to characterize the feasibility. The relationship between ultrasound measurements and clinical outcomes will be explored. The results obtained will document feasibility issues and provide preliminary results will lay the groundwork for a large scale study.

The iliotibial band (ITB) is a complex structure in which morphometry (shape, thickness, cross-sectional area) and viscoelastic properties remain poorly understood. While some hypothesize that the pain originates from friction of the ITB on the femoral condyle during knee flexion, others affirm that it is rather a compression of the ITB on the tissue underlying fat, which is highly vascularized and innervated. Current treatments in physiotherapy are based, in part, on the theory that stiffness in the ITB may contribute to iliotibial band syndrome (ITBS), resulting in prescription of stretching exercises in most rehabilitation programs. However, the plausibility of this theory remains to be demonstrated with valid and reliable instruments. Standard-mode (B-mode) ultrasound is gaining popularity for assessing ITB morphometry. However, these data remain to be correlated with the clinical symptomatology. Sonoelastography (SWE), on the other hand, is used to assess tissue stiffness. Recent studies have attempted to assess the stiffness of ITB under different experimental conditions, but these have methodological flaws (low power) and they are carried out in an asymptomatic population. This project is a first step to fill the gaps on ITB morphometry and stiffness values and explore the potential association between these factors and the clinical profile of SBIT. The primary objective is to evaluate the study the feasibility of the protocol by documenting the variables associated with this concept. Secondary objectives are: 1) To measure the stiffness of the distal BIT in runners with and without ITBS; 2) Describe the morphometry of the distal BIT in the two groups of runners; 3) Compare ITB morphometry and stiffness between the two groups of runners and 4) Investigate the association between ultrasound variables and ITBS signs and symptoms.