Structure and Function of Meniscal Horn Attachments

Michigan Technological University, Houghton MI

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Abstract

DESCRIPTION (provided by applicant): Menisci function to distribution load and increase stability of the knee joint. Both partial and complete meniscectomy have been shown to increase the incidence of osteoarthritis. Meniscal replacement with allograft, synthetic or tissue engineered replacements, could act to reduce the occurrences of osteoarthritis. The success of meniscal replacements depends on their ability to restore normal meniscal function both biologically and biomechanically. Meniscal attachments are critical for proper meniscal function. Since rupture of the horn attachments of the menisci are rare it is likely that a gradient in mechanical properties and biochemical make-up exists through the attachment. Previous computational studies have shown that the material properties of the attachments dramatically affect the contact pressures on the meniscus and without gradual transition in the properties, large stress concentrations at the insertion zones into the meniscus and the bone are evident. Additionally, these stress concentrations are seen mostly in the deeper zones of the tissue, not on the proximal surface. Previous research has only documented the material properties on the proximal surface of the tissue. The goal of this project is to quantify the microstructure and material properties of the meniscal attachment where it inserts into the meniscus and bone, as well as in the deep layers of the tissue. Specifically this project will 1) determine the local fluid pressures in the deep layers of the tissue during both physiological loading (static and dynamic) levels and failure testing using a fibre-optic pressure microsensor, 2) determine the transverse material properties 2) quantify the collagen orientation in the transition zone from fibrocartilage to ligamentous attachment using scanning electron microscopy, and lastly the project will 3) determine the mechanical properties of the transition zones into the subchondral bone at the nanolevel. The results of these aims will then be used to quantify a relationship between the structure and function of the native meniscal attachments and validate the current finite element model of the attachments. This data can then be used to develop, design and evaluate meniscal replacements, including tissue engineered constructs. A successful meniscal replacement will work to prevent joint degeneration following meniscectomy. PUBLIC HEALTH RELEVANCE: Menisci within the knee joint function to protect the underlying articular cartilage from degenerative osteoarthritis. The absence of a healthy meniscus can inhibit this function. The goal of this research is to determine the structure and function of native meniscal attachments such that effective meniscal replacements or therapies can be developed to reduce the incidences of knee joint osteoarthritis.