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Distal radius fractures are the single most common type of fracture suffered among the adult population. Presently, clinical decision making regarding optimal treatment is inconclusive. The goal of this thesis was to design, develop, and biomechanically test a novel implant for the stabilization of distal radius fractures. The novel implant is intended to provide a minimally invasive, low cost alternative to locked volar plates, while still permitting an earlier return to function. The implant consists of an angled bar with a sharp cutting edge and is inserted using a minimally invasive approach through the radial styloid. Surgical instrumentation was designed to facilitate the procedure in a controlled manner. To determine whether the implant would be capable of providing an early return to function, biomechanical tests were conducted both experimentally and numerically. Biomechanical testing showed that mechanical fixation with the novel implant does not support and early return to function.

Bone is porous and has a complex microstructure. This study considers the effect of microstructural morphology on the macrolevel mechanical properties of bone. Improved incorporation of such properties is required to advance current finite element approximations of bone behaviour. A technique to computationally generate realistic trabecular bone microstructures is developed. This provides the possibility of examining the effect of different microstructures on the macrolevel mechanical behaviour of bone. They would also permit direct incorporation of bone microstructure in macroscale finite element analyses without the prohibitive computational and experimental costs of donor-image based mesh generation. Micro- finite-element analyses are used for the first time to evaluate the macrolevel orthotropic elastic constants of cortical bone resulting from variations of microstructural morphology. It is concluded that the ratio of canal volume to tissue volume is the most powerful predictor of cortical bone elastic constants and that considerable periosteal-endosteal variations in these constants can develop with bone loss. The role of microstructure in cortical bone toughness is investigated using nano- finite-element analyses of murine cortical bone samples to simulate the initiation and propagation of microcracks. Results confirm the experimentally observed ability of canal and lacuna pores to act as stress raisers, thereby guiding the growth of microcracks. A novel and numerically efficient strain-based plasticity algorithm is presented which permits easy incorporation of strength anisotropy in finite element analyses of bone. The previously evaluated elastic properties of cortical bone are combined with the developed plasticity algorithm to conduct a detailed macro-finite-element investigation of external fixation of tibial midshaft fractures. Old patients are found to be at considerably higher risk of implant loosening under both unilateral and Ilizarov fixation, compared to younger patients.

Thesis (M.D.)--University of Adelaide, Dept. of Orthopaedics and Trauma, 1999? / Bibliography: leaves 216-231.

Thesis (doctoral)--University of Uppsala, 1983. / Includes bibliographical references (p. 36-41).

Bibliography: leaves 216-231. / xvii, 231, [99] leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines the sliding capability of external fixators under load and describes the development and testing of an external fixator capable of providing axial cyclic motion to a fracture site while a patient is walking. / Thesis (M.D.)--University of Adelaide, Dept. of Orthopaedics and Trauma, 1999?

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Orthopaedic Surgery / Master / Master of Philosophy

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Description based on contents viewed Oct. 14, 2008; title from PDF t.p. Includes bibliographical references (p. 66-71).

Thesis (doctoral)--Malmö University, Sweden, 2001. / Added t.p. with thesis statement inserted. Includes bibliographical references.