A 3D Motion Phantom for Assessing the Accuracy and Precision of Dynamic Magnetic Resonance Measurement of In Vivo Knee Kinematics

Measurement of in vivo knee kinematics can provide useful insight into disease, injury, and clinical treatment. Cartilage loading patterns are of particular interest while studying the progression of osteoarthritis [1]. However, inferring cartilage contact from skeletal kinematics requires high resolution volumetric models of cartilage surfaces and accurate skeletal positions and orientations. This is a challenging requirement at the knee, which exhibits substantial translation and non-sagittal rotation during normal activities such as gait [2]. We have recently introduced a novel 3D cine magnetic resonance (MR) imaging technique to measure in vivo tibiofemoral kinematics [3]. The purpose of this study was to develop a MR-compatible motion phantom that can generate repeatable 3D skeletal motion suitable for quantifying the accuracy and precision of kinematics derived from dynamic MRI.