Published in:
Open Access
01-12-2020 | Magnetic Resonance Imaging | Research Article
An MRI-compatible varus–valgus loading device for whole-knee joint functionality assessment based on compartmental compression: a proof-of-concept study
Authors:
Oliver Said, Justus Schock, Nils Krämer, Johannes Thüring, Lea Hitpass, Philipp Schad, Christiane Kuhl, Daniel Abrar, Daniel Truhn, Sven Nebelung
Published in:
Magnetic Resonance Materials in Physics, Biology and Medicine
|
Issue 6/2020
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Abstract
Objective
Beyond static assessment, functional techniques are increasingly applied in magnetic resonance imaging (MRI) studies. Stress MRI techniques bring together MRI and mechanical loading to study knee joint and tissue functionality, yet prototypical axial compressive loading devices are bulky and complex to operate. This study aimed to design and validate an MRI-compatible pressure-controlled varus–valgus loading device that applies loading along the joint line.
Methods
Following the device’s thorough validation, we demonstrated proof of concept by subjecting a structurally intact human cadaveric knee joint to serial imaging in unloaded and loaded configurations, i.e. to varus and valgus loading at 7.5 kPa (= 73.5 N), 15 kPa (= 147.1 N), and 22.5 kPa (= 220.6 N). Following clinical standard (PDw fs) and high-resolution 3D water-selective cartilage (WATSc) sequences, we performed manual segmentations and computations of morphometric cartilage measures. We used CT and radiography (to quantify joint space widths) and histology and biomechanics (to assess tissue quality) as references.
Results
We found (sub)regional decreases in cartilage volume, thickness, and mean joint space widths reflective of areal pressurization of the medial and lateral femorotibial compartments.
Discussion
Once substantiated by larger sample sizes, varus–valgus loading may provide a powerful alternative stress MRI technique.