Application of Magnetic Resonance Imaging for in vitro investigation of meniscus and cartilage degeneration in the knee

Damage to the meniscus and articular cartilage in the knee can lead to loss of function and compromise joint stability. This has led to the development of in vitro models to investigate the biomechanics and biotribological response of cartilage and menisci. In high-volume laboratory studies of cartilage tribology, it is important to measure cartilage loss after experiments. In order to understand the relationship between the structure and function of the meniscus in health and disease, it is essential to interrogate the internal structural components of the meniscus. The aims of this project were to optimise protocols for magnetic resonance imaging (MRI) of menisci and articular cartilage in the knee in order to gain an increased understanding of their structure, and to detect and quantify morphological changes. A novel porcine medial knee model was developed for creation of physiological cartilage damage using a friction simulator. The cartilage damage models were subject to in vitro MRI quantification at both 9.4 Tesla and 3.0 Tesla for the first time. The two customised MRI-based wear quantification methods were validated using Pycnometer measurements. In addition, a novel approach was developed at 9.4T MRI to non-destructively investigate intrameniscal architecture and damage. Cartilage defect models were successfully created on the femoral condyle and tibia after friction simulator tests. The follow-up MRI investigation demonstrated the capability of MRI to assess cartilage defects using laboratory and clinical systems. At both of 9.4T and 3.0T, the two quantification methods were in excellent agreement with each other and with Pycnometer measurements. An optimised 10-hour 3D scan at 9.4T could clearly demonstrate 3D intrameniscal architecture. The MRI quantification protocols showed promise for the non-destructive examination and quantification of cartilage defects in a large range of animal/human tissues after biomechanical/biotribological experiments. MRI at ultra-high-field strength also showed promise for the non-destructive examination of the intrameniscal structure in a 3D manner. The proof of concept measurements presented in this study illustrates the potential of non-destructive 3D MRI microscopy to bring a unique contribution to the field of functional cartilage/meniscus biomechanics and biotribology.