Reliability of Continuous Shear Wave Elastography in the Pathological Patellar Tendon

Area of Science:

• Biomedical Engineering
• Musculoskeletal Imaging
• Sports Medicine

Background:

• Patellar tendon injuries, including overuse and those from anterior cruciate ligament reconstruction (ACLR), impact patient function.
• Accurate quantification of patellar tendon stiffness is crucial for guiding clinical management.
• Continuous shear wave elastography (cSWE) offers a method to assess tendon viscosity and shear modulus, but its reliability in the patellar tendon requires validation.

Purpose of the Study:

• To evaluate the interrater reliability, intrarater reliability, and between-day stability of cSWE for assessing patellar tendon properties.
• To establish the reliability of cSWE in both healthy individuals and those with patellar tendinopathy or a history of ACLR.

Main Methods:

• Recruited participants with patellar tendinopathy (n=13), history of ACLR (n=9), and healthy controls (n=13).
• Performed cSWE measurements four times over two days using multiple raters.
• Calculated intraclass correlation coefficients (ICC) and minimum detectable change (MDC95%) to assess reliability.

Main Results:

• Demonstrated good to excellent between-day stability for viscosity (ICC=0.905) and shear modulus (ICC=0.805).
• Minimum detectable change for viscosity was 8.3 Pa·seconds and for shear modulus was 27.4 kPa.
• Interrater reliability was found to be less reliable, with ICC values of 0.591 and 0.532.

Conclusions:

• Continuous shear wave elastography (cSWE) is a reliable tool for tracking changes in patellar tendon viscoelastic properties over time.
• The study recommends using a single rater for cSWE measurements to optimize reliability.
• Findings support the use of cSWE for monitoring patellar tendon health and recovery.