Towards preservation of the natural knee: State-of-the-art approaches to understand the kinematics and tissue mechanics of human menisci in vivo.

Meniscal injuries are the second most common injury to the knee, leading to joint degeneration and mobility issues. Towards the preservation of natural knees through the development of artificial menisci, the aim of this research is to investigate kinematics and tissue mechanics of human knee joint menisci in the living body during dynamic activities of daily living. The novelty of this study is the in vivo investigation of knee joint menisci during complete gait cycles combined with subject-specific modelling rather than investigation using cadaveric menisci in vitro or functional MRI for static weight-bearing in vivo. In other words, we will analyse knee joint menisci kinematics and material mechanics for the first time under physiologically relevant kinematic conditions, including both the loaded and unloaded phases of gait. This new understanding will be facilitated by developing new methodological innovations that combine advanced imaging and computational modelling methods. To acquire the advanced images, the PI will collaborate with the project partner, using the recently completed high-frequency tracking dual-plane fluoroscopy system to assess joint kinematics at a resolution that has not been possible until now. To ensure the highest levels of accuracy available, the state-of-the-art medical imaging facilities at the Swiss Centre for Medical Imaging (SCMI), Balgrist Campus, Zürich, will be used, specifically the 7 Tesla Magnetic Resonance Imaging (MRI) system and photon-counting Computer Tomography (CT), which is the first of its kind in Europe. Images of the highest quality available will then form the basis for the development of finite element models of the knee joints, including menisci with a advanced material representations.
Our research will generate a new combined understanding of knee joint meniscal kinematics and material mechanics, based on their functional movement and strain patterns during complete gait cycles. Translation of novel research findings on the physiological functionality of the natural menisci from this project will directly guide the further development of meniscal implant designs, including novel implant materials, and foster a new field of biomechanical investigation into improving the preservation of natural knees.