Defining normal enthesis stiffness range in a healthy adult population

Area of Science:

• Musculoskeletal imaging
• Rheumatology
• Biomedical engineering

Background:

• Enthesis stiffness is crucial for understanding tendon health and function.
• Shear wave elastography (SWE) is an emerging ultrasound technique for non-invasively assessing tissue stiffness.
• Demographic factors may influence enthesis mechanical properties.

Purpose of the Study:

• To investigate the relationship between volunteer demographics (age, gender, BMI) and enthesis stiffness.
• To evaluate the intra- and interobserver agreement of SWE measurements in various entheses.
• To determine the influence of age and gender on enthesis stiffness.

Main Methods:

• Ninety-eight healthy volunteers underwent SWE on quadriceps, suprapatellar, infrapatellar, and Achilles entheses.
• Stiffness was quantified using shear wave velocity (SWV).
• Statistical analyses included Mann-Whitney, Wilcoxon signed-rank, Spearman correlation, multiple linear regression, and Kruskal-Wallis tests.

Main Results:

• No significant difference in SWV was observed between genders.
• Significant differences in SWV were found between left and right Achilles entheses.
• Age showed a moderate negative correlation with SWV in quadriceps and weak negative correlations in suprapatellar and left Achilles entheses.
• Age was a significant predictor of stiffness in quadriceps, suprapatellar, and left Achilles entheses.
• Good intra- and interobserver agreement (0.78–0.89) was achieved for all entheses.

Conclusions:

• SWE is a reproducible method for quantifying enthesis stiffness.
• Age is a significant demographic factor influencing SWV in specific entheses.
• Achilles enthesis exhibited the highest SWV across all age groups.
• The findings contribute to understanding enthesis biomechanics and the impact of demographics.