A Pilot Study to Quantify In Vivo Meniscus Mechanics Under Load Using Magnetic Resonance Imaging

Meniscus tears compromise its mechanical function, leading to impaired joint loading and, if left untreated, increase risk of further joint degeneration. Surgical repair can be successful for certain tear patterns. Establishing new methods quantifying in vivo meniscus mechanics under weight-bearing facilitates improvements in surgical techniques and postoperative care. The goal of this study was to establish a method for quantifying meniscus mechanics under loading in vivo using magnetic resonance imaging (MRI). A custom MRI-compatible knee loading device was instrumented with the capability of applying loads up to 700N at variable flexion angles. To evaluate the device, the medial and lateral menisci of healthy young participants and participants with knee pathologies were evaluated. MRI was acquired when the knees were loaded under 10% and 50% bodyweight at 0° extension and 30° flexion. Displacements were quantified in both menisci and articular cartilage. All participants completed the knee loading protocol without issue or discomfort. The participants with knee pathologies exhibited greater amounts of displacement compared to the healthy participants. Cartilage strain was consistent and within expected physiological range amongst all participant groups. This study demonstrated the safety and effectiveness of using an in vivo MRI-compatible knee loading device that can apply physiological compressive loads at varying knee flexion angles. Our results provide proof-of-concept of this technique to quantify altered joint kinematics in surgical patients with meniscus or cartilage pathologies. The novel methodology substantiates further study on patients who receive meniscus surgical procedures.