Like many medical oriented fields, orthopaedics has struggled in transferring technology between preclinical and clinical research and in understanding the intersection of mechanics and biology at the body, joint, tissue, and cellular levels. This dissertation aims to advance methods for multiscale mechanics in orthopaedic research by 1) evaluating tissue mechanics changes caused by hydration, cellular removal, and physical modification of the knee meniscus and 2) scaling modern gait technology for use in rodents to study behavioral, mechanical, and biological changes in two preclinical models of osteoarthritis.
1) Orthopaedic allografts, synthetic replacements, and tissue engineered constructs must balance biological viability and mechanical integrity, which interact on different levels. This challenge is made more difficult by the varying methods used to validate orthopaedic tissue engineered constructs. For example, meniscus tears are the most common knee injury in the United States, but a long-term replacement is not yet available, and potential replacements often face mixed results. Thus, this work examines the viscoelastic properties of the knee meniscus in different testing scenarios and structural modifications.
2) Traditionally, technologies to assess the functional capabilities of an orthopaedic disease are created for human research, such as force plates and motion capture systems. However, to simultaneously study the mechanics and biology of diseases such as osteoarthritis, these technologies must also be developed for preclinical animals. Adapting these technologies for preclinical models not only helps bridge preclinical and clinical research, but also provides much needed quantitative measures of animal behavior and pain. Thus, this work improves methods to assess gait mechanics in rodents and studies rodent gait in two models of osteoarthritis.
Although the ability to study the interactions of biomechanics from the body down to the cell in a single model remains in the future, this dissertation serves to improve orthopaedic research by evaluating two areas where improvements are needed: tissue and gait mechanics in preclinical research.