The objective of this thesis is to biomechanically evaluate a novel Double bundle technique for UCL reconstruction designed to accelerate recovery time and minimize gap formation. Excluding UCL surgery, ligament reconstruction procedures typically require an average of 6 months of recovery time. UCL reconstructive surgery requires approximately 1-2 years of recovery time. Valgus instability of the elbow is characterized by attenuation, or frank rupture of the UCL from repetitive and excessive valgus loads. This research compared the valgus stability, gap formation, and ultimate strength that resulted from the cyclic valgus loading at 30 ° of flexion of 3 techniques for reconstruction of the UCL: the Jobe, Docking, and a novel Double bundle procedure. A servocontrolled materials testing machine applied a cyclic valgus load to white cortical Sawbones elbow complex models while a 3D electromagnetic motion tracking system recorded the valgus displacement of the UCL reconstructions. The valgus stability, gap formation, and ultimate strength were measured at 50, 100, 200 and 600 cycles or the cycle at which failure occurred. The mean peak load to failure was 30N for the Jobe reconstructions, and 50N for both the Docking and Double bundle reconstructions. Both the Docking and the Double bundle reconstructions sustained a higher load to failure than the Jobe reconstruction. None of the separate univariate ANOVAs of the biomechanical parameters of each reconstruction were statistically significant. Although there was no statistically significant difference, a small standard deviation in all measured values indicated consistency in testing methodology. The power or sample size is not high enough to state with confidence that statistically there is no difference.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Liang-Wu Cai / A computational system is built for conducting deterministic simulations of three-dimensional multiple scattering of elastic waves by spherical inclusions. Based on expansion expression of elastic wave fields in terms of scalar and vector spherical harmonics, analytically exact solutions of single scattering and multiple scattering are obtained, implemented and verified. The verification is done by using continuities of displacement and surface traction at the interface between an inclusion and host medium, energy conservation and published results. The scatterer polymerization methodology is extended to three-dimensional multiple scattering solution. By using this methodology, an assemblage of actual scatterers can be treated as an abstract scatterer. This methodology is verified by using different approaches, with or without scatterer polymerization, to solve a physically the same multiple scattering problem. As an application example, band gap formation process for elastic wave propagation in cubic lattice arrangements of spherical scatterers is observed through a series of numerical simulations. Along the direction of the incident wave, scatterer arrangements are viewed as comprising layers of scatterers, within which scatterers form a square grid. Starting from one layer and by increasing the number of layers, near-field forward wave propagation spectra are computed as the number of layers increases. These simulations also demonstrates that the computational system has the capability to simulate multiple scattering solutions of elastic waves in three-dimension.