Design of an MR and μCT Compatible Ovine Stifle Joint Loading Device toAssess the Trajectory of Osteoarthritis Disease Progression
My research involved building a device to hold and apply loads to a sheep knee so that I can investigate the response of the menisci using medical imaging techniques. The menisci act like shock absorbers of the knee and sit in the joint space created by the patella and the ends of the tibia and femur. When loading in the knee is altered the menisci can be compromised and deteriorate. When the menisci are damaged, the ability to load share decreases which leads to further damage of the whole joint. In order to investigate the soft tissue of the knee non-invasively, I designed and built a joint loading device that is compatible for two medical imaging modalities: magnetic resonance (MR) imaging and micro-computed tomography (μCT). This MR and μCT compatible device was built to house an intact ovine (sheep) stifle (knee) from the mid femur to mid tibia. This device was designed to apply physiologic loads up to 1.5 to 2 times body weight while maintaining the knee at varying flexion angles (40o-60o) representing the stance phase of gait. These loads were applied with a custom built pneumatic cylinder during simultaneous image acquisition. The pneumatic cylinder applied a load to the potted femur axially, while the tibia was potted into a spherical Delrin® cup that was free to rotate. The entire device, including the femur, patella, tibia and pneumatic cylinder fit within a 14cm diameter acrylic tube to allow insertion into the bore of the scanners.
The objective of this work was to study the response of the meniscus to physiologic loading. Quantification of this response in normal tissue will aid in determining variations due to injury, disease and healing; and provide insight into the trajectory of tissue degeneration that leads to osteoarthritis.
The Biomechanical Analysis of Knee Osteoarthritis
Please note that I am currently looking for MSc. and PhD candidates to pursue some of the research topics bleow.
MSc Completed - 2008
I am designing, building, and testing a laser-based measurement system that we will use to measure the complex shape and cross-sectional area of ligaments and tendons. It is expected that the measurements produced by this system will be faster, more accurate and more reliable than existing manual measurement systems. We will also be able to measure the changing cross-sectional area of ligaments and tendons as they undergo tensile tests in a materials testing system. Armed with these area measurements, we can get a better picture of the true biomechanical properties of the tissue being tested. Ligaments and tendons are important tensile-bearing structures in the body, and characterizing their properties is valuable for understanding soft tissue injury and repair.
A laser-based measurement system that will measure complex shapes and cross-sectional areas
My research is focused on biomechanical analysis of knee osteoarthritis using in vitro mechanical testing and finite element techniques. More specifically, I am aiming to quantify the effects of meniscal injury, joint alignment, and load type on risk of cartilage degradation. I also plan to use regression analysis to develop a biomechanically-based equation to assess risk of knee osteoarthritis progression. Ideally, this work will contribute to improved clinical diagnosis and ultimately better quality of life for patients affected by knee osteoarthritis.
The Structure and Function of Healthy and Osteoarthritic Posteromedial Knee Joint Capsule
Justin Steeds - MSc in Biological Engineering, Completed 2010.
This research characterized the structure and function of the posteromedial knee joint capsule in both healthy and osteoarthritic knee joints using uniaxial testing methods (shown in the figure below), polarized light microscopy, and environmental scanning electron microscopy. Biaxial testing was also performed on healthy tissue. The results of this work showed that the capsule tissue consisted of a bimodal distribution of collagen fibre orientation oblique to the medial lateral anatomic axis. Preliminary work suggested that the osteoarthritic tissue had remodeled, with only a single major axis coincident to the medial lateral axis. This work will improve our understanding of the progression of osteoarthritis, its effect on soft tissue in the knee joint, and of the remodeling process soft tissues undergo following injury and disease.