Normative Data of Supraspinatus Muscle Shear Wave Elastography in Healthy Shoulders: A Cross-Sectional Study

Background/Objectives: In the shoulder region, shear wave elastography (SWE) has been used to obtain data from multiple muscles. However, there is still a lack of evidence regarding normative values for the supraspinatus muscle. The aim of this study is to estimate the range of normative values and to evaluate the relationship between SWE measurements and isometric strength. Methods: A cross-sectional study with 46 healthy subjects was conducted. Data regarding the SWE of supraspinatus muscle at rest and during contraction and isometric elevation strength were collected. Ordinal cumulative probability models were implemented to calculate normative values based on age and sex. Results: There was a significant increase in muscle stiffness from rest to contraction (3.97; 95% CI, 3.52 to 4.43), but there were no differences between males and females. The ordinal regression models showed a relationship between age and SWE at rest (coefficient, 0.08; 95% CI, 0.01 to 0.14), but not during contraction, and there was no significant age-sex interaction. Normative values of the median and 25th and 75th percentiles were provided based on individuals' age and sex. There was no correlation between SWE measurements and strength values. Conclusions: Normative values for supraspinatus muscle SWE measurements at rest and during contraction were obtained. These data can help clinicians to interpret measurements of their patients with shoulder disorders.