An MRI-compatible loading device to assess knee joint cartilage deformation: Effect of preloading and inter-test...

Area of Science:

• Biomedical Engineering
• Orthopedics
• Medical Imaging

Background:

• Cartilage deformation under load may predict joint degeneration.
• Longitudinal, patient-specific quantification of cartilage deformation is needed.
• Reproducible in-vivo measurements are essential for clinical application.

Purpose of the Study:

• Design an MRI-compatible device for controlled axial loading and repeatable tibiofemoral positioning.
• Determine optimal load duration for reproducible cartilage deformation measurements in a clinical setting.

Main Methods:

• A displacement-controlled loading device made of MRI-compatible materials was developed.
• Four volunteers underwent unloaded, immediate loaded (50% body weight), and delayed loaded (12 min post-load) MRI scans.
• Tibiofemoral position and cartilage deformation were measured between repeat loaded scans.

Main Results:

• The device ensured repeatable tibiofemoral positioning (<1mm translation, <2° rotation).
• Delayed scans showed more consistent cartilage deformation measurements than immediate scans.
• Tibiofemoral positioning was repeatable within patients.

Conclusions:

• The developed loading device enables reproducible tibiofemoral positioning for longitudinal studies.
• Delayed MRI acquisition following loading enhances measurement reproducibility for cartilage deformation.
• This approach supports clinical assessment of joint degeneration predisposition.