Osteoporosis is a disease prevalent in older adults, characterized by increased bone porosity resulting in significant fracture risk. Orthopaedic implants are designed and validated against cadavers from the general ‘healthy’ population, but little is known about their response in osteoporotic bone. Orthopaedic implants can also be developed using synthetic bones, if they have been demonstrated to be representative of healthy bone, and offer a number of advantages. To date, no synthetic femur has been validated for the osteoporotic population. The purpose of this study was to assess novel synthetic femurs for representing this population. Custom jigs were manufactured to test two sets of ten synthetic femurs and five isolated cadaveric femurs in four-point bending, torsion, axial compression, axial failure, and screw pullout, using an Instron mechanical testing machine to record load-displacement data. Statistical significance was found in bending, torsion, and screw pullout between both synthetic sets and cadavers using one-way ANOVA with post-hoc Tukey analysis. In all instances, the synthetic femurs had lower coefficients of variation than natural specimens. Both synthetic and cadaveric femurs were CT scanned prior to testing. The data were used to measure key anatomical details and to develop a series of numerical models of the synthetic bones, using Materialize Mimics® and ABAQUS® software, evaluated using axial and bending data. The model was modified by reducing cortical thickness and modulus in an attempt to make the synthetic model better represent osteoporotic bone. Establishing synthetic femurs as suitable replacements for osteoporotic bone allows for improved orthopaedic implant development. The digital model constructed allows the synthetic to be further analyzed, improving expected response of the synthetic bones. These synthetic bones could provide a foundation for development of effective orthopaedics for this population. / Thesis / Master of Applied Science (MASc) / The considerations and parameters in the design of orthopaedic implants for osteoporotic bone are relatively unknown. Orthopaedic implants can be evaluated with synthetic bones, which offer a number of advantages to natural specimens, assuming they are sufficiently representative of natural bone. No physical synthetic model yet exists that represents an osteoporotic femur. In the present work, synthetic femurs were subjected to bending, torsion, axial compression, and screw pullout and compared to natural osteoporotic specimens. The synthetics were significantly different to natural specimens in bending, torsion, and screw pullout. A numerical model was created, evaluated, and tested in finite element software alongside modified models with reduced modulus and cortical thickness to assess stiffness. Recommendations were made to improve the accuracy of a future synthetic model. The synthetic femurs tested were not representative of osteoporotic femurs, but may be feasible alternatives with minor modifications and could be useful in future orthopaedics design.

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.

No description available.