Engineering Commons^™

Material Properties Are Related To Stress Fracture Callus And Porosity Of Cortical Bone Tissue At Affected And Unaffected Sites, Rachel C. Entwistle,, Sara C. Sammons, Robert F. Bigley, Scott J. Hazelwood, David P. Fyhrie, Jeffery C. Gibeling, Susan M. Stover

Biomedical Engineering

Stress fractures are overuse injuries of bone that affect elite athletes and military recruits. One response of cortical bone to stress fracture is to lay down periosteal callus. The objectives of this study were to determine if material properties are different among bones with different stages of stress fracture callus, at both a callus site and at a distal site. Cortical specimens were mechanically tested to determine their stress–strain response. Material property differences were examined using nonparametric and regression analyses. At the callus site, material properties were low during the earliest stages of callus, higher with increasing callus maturity, but …

A Biomechanical Comparison Of Locked Plate Fixation With Percutaneous Insertion Capability Versus The Angled Blade Plate In A Subtrochanteric Fracture Gap Model, Brett D. Crist, Afshin Khalafi, Scott J. Hazelwood, Mark A. Lee

Biomedical Engineering

Objectives: The angled blade plate has been the historical standard in fixed-angle extramedullary subtrochanteric femur fracture fixation, but it requires an extensile lateral approach to the femur. Little formal evaluation exists for specifically designed percutaneous extramedullary implants. The purpose of this study was to compare 3 locked plating constructs, all with percutaneous insertion capability, with the standard 95-degree angled blade plate to determine whether specifically designed fixed-angle extramedullary implants for subtrochanteric femur fractures were biomechanically comparable to the angled blade plate.

Methods: Forty composite adult femurs were divided into 4 equal groups. The constructs evaluated included a 95-degree angled blade …

Compliance Calibration For Fracture Testing Of Anisotropic Biological Materials, J. A. Creel, S. M. Stover, R. B. Martin, D. P. Fyhrie, S. J. Hazelwood, J. C. Gibeling

Biomedical Engineering

The compliance technique has been used to monitor crack length during fracture and fatigue testing of materials. Difficulties arise when this technique is applied to anisotropic biological materials such as bone. In this tutorial, two different methods of analyzing compliance calibration data are described: the standard ASTM method and a new approach developed by the authors specifically for anisotropic materials. An example is given showing how data from equine cortical bone can be analyzed. In this example, calibration tests were conducted on thirty-six three point bend specimens machined from the middiaphysis of six pairs of equine third metacarpal bones. Cracks …

A Modification To The Group Delay And Simulated Annealing Technique For Characterization Of Peripheral Nerve Fiber Size Distributions For Non-Deterministic Sampled Data, Robert B. Szlavik

Biomedical Engineering

The ability to determine the characteristics of peripheral nerve fiber size distributions would provide additional information to clinicians for the diagnosis of specific pathologies of the peripheral nervous system. Investigation of these conditions, using electro-diagnostic techniques, is advantageous in the sense that such techniques tend to be minimally invasive yet provide valuable diagnostic information. One of the principal electro-diagnostic tools available to the clinician is the nerve conduction velocity test. While the peripheral nerve conduction velocity test can provide useful information to the clinician regarding the viability of the nerve under study, it is a single parameter test that yields …

A Simple, Yet Effective, Demonstration Of Polymeric Mechanical Behavior, Lanny Griffin, Jeffrey Swab

Biomedical Engineering

Developing an appreciation for the mechanical behavior of polymers materials in a lecture mode can be challenging for students if they have not bad the benefit of a laboratory experience . We have developed a simp le demonstration of thermoplastic polymeric behav ior using low-density polyethylene bags. The demonstration illustrates strengthening, rate effects, and directionality of strengthening and stiffness. Following the demonstration, students are better ab le to articulate the influence of structure, properties, processing , and performance as it applies to thermoplastic polymers.

Theoretical Analysis Of Alendronate And Risedronate Effects On Canine Vertebral Remodeling And Microdamage, Xiang Wang, Antonia M. Erickson, Matthew R. Allen, David B. Burr, R. Bruce Martin, Scott J. Hazelwood

Biomedical Engineering

Bisphosphonates suppress bone remodeling activity, increase bone volume, and significantly reduce fracture risk in individuals with osteoporosis and other metabolic bone diseases. The objectives of the current study were to develop a mathematical model that simulates control and 1 year experimental results following bisphosphonate treatment (alendronate or risedronate) in the canine fourth lumbar vertebral body, validate the model by comparing simulation predictions to 3 year experimental results, and then use the model to predict potential long term effects of bisphosphonates on remodeling and microdamage accumulation. To investigate the effects of bisphosphonates on bone volume and microdamage, a mechanistic biological model …

A Numerical Approach For Predicting The Impact Of Vascular Architecture On Blood Flow During Ischemic Repair, Stephanie Ann Wood, Shilpi Ghosh, Kevin Jones, Gabriel Gruionu, Trevor R. Cardinals

Biomedical Engineering

Abstract of conference presentation.

Functional Vasodilation Following Murine Chronic Hindlimb Ischemia, Matthew David Yocum, Trevor R. Cardinal

Biomedical Engineering

Abstract of conference presentation.

Fatigue Strength Of Common Tibial Intramedullary Nail Distal Locking Screws, Lanny V. Griffin, Robert M. Harris, Joseph J. Zubak

Biomedical Engineering

Premature failure of either the nail and/or locking screws with unstable fracture patterns may lead to angulation, shortening, malunion, and IM nail migration. Up to thirty percent of all unreamed nail locking screws can break after initial weight bearing is allowed at 8–10 weeks if union has not occurred. The primary problem this presents is hardware removal during revision surgery. The purposes of our study was to evaluate the relative fatigue resistance of distal locking screws and bolts from representative manufacturers of tibial IM nail systems, and develop a relative risk assessment of screws and materials used. Evaluations included quantitative …

Alterations In Femoral Strain Following Hip Resurfacing And Total Hip Replacement, C. R. Deuel, A. A. Jamali, S. M. Stover, S J. Hazelwood

Biomedical Engineering

Bone surface strains were measured in cadaver femora during loading prior to and after resurfacing of the hip and total hip replacement using an uncemented, tapered femoral component. In vitro loading simulated the single-leg stance phase during walking. Strains were measured on the medial and the lateral sides of the proximal aspect and the middiaphysis of the femur. Bone surface strains following femoral resurfacing were similar to those in the native femur, except for proximal shear strains, which were significantly less than those in the native femur. Proximomedial strains following total hip replacement were significantly less than those in the …

Abnormal Collateral Artery Vasoactivity Following Chronic Ischemia, Trevor Cardinal, Thomas J. Kesler, Matthew D. Yocum

Biomedical Engineering

No abstract provided.

A Numerical Approach To Determine The Impact Of Network Remodeling On Blood Flow, Trevor Cardinal, Shilpi Ghosh, Stephanie A. Wood, Gabriel Gruionu

Biomedical Engineering

No abstract provided.