Reliability of ultrasound shear-wave elastography in assessing tensor fascia latae, gluteus medius, and iliotibial band elasticity in health individuals

Purpose: Gluteus medius (GMed), tensor fascia latae (TFL), and iliotibial band (ITB) play important roles in stabilizing the hip joint and are often prone to overuse syndromes such as greater trochanteric pain syndrome and runner's knee. Shear-wave elastography (SWE) presents a new avenue for rapidly assessing these structures in an outpatient setting. This study aims to assess the intra- and interobserver reliability of sWE in evaluating the GMed, TFL, and ITB. Materials and Methods: Twelve healthy volunteers (6 men and 6 women) were examined by two physiatrists using SWE. To assess inter-observer reliability, both physiatrists measured the thickness, velocity, and stiffness of GMed, TFL, and proximal and distal ITB. One physiatrist repeated the same measurements under identical conditions one week later to assess intra-observer reliability. Intra-class correlation coefficients (ICC) were calculated to evaluate reliability. Results: Inter-observer measurements showed poor reliability (ICC < 0.4) for all parameters, except for GMed thickness (ICC=0.412), which was moderately reliable. Intra-observer measurements showed varying degrees of reliability, with TFL thickness (ICC=0.733), ITBP thickness (ICC=0.592), ITBD velocity (ICC=0.634), and ITBD stiffness (ICC=0.701) demonstrating moderate reliability. However, no excellent ICC scores were observed across both intra- and inter-observer assessments. Conclusion: While SWE demonstrates promise in assessing hip stabilizers, its inconsistent reliability across different parameters highlights the need for further research. Comparative studies involving healthy and pathological groups are needed for better understanding of SWE's applicability in clinical settings.