Engineering Commons^™

Acromial Insufficiency Fractures In Reverse Total Shoulder Arthroplasty: A Biomechanical Study, Alicia Kerrigan

Electronic Thesis and Dissertation Repository

Reverse total shoulder arthroplasty (RTSA) is increasingly utilized in the aging population, with a growing list of surgical indications including rotator cuff tear arthropathy, proximal humerus fractures, and revision arthroplasty. Acromial insufficiency fractures following RTSA are poorly understood, difficult to diagnose, and associated with inferior clinical outcomes. There is limited knowledge in the literature regarding the etiology of post-operative acromial fractures. The purpose of this study is to evaluate the role of implant parameters on acromial strain following RTSA.

Using a cadaveric model, a custom designed modular RTSA system was implanted that allowed for evaluation of modifiable parameters including glenoid …

Hip And Knee Biomechanics For Transtibial Amputees In Gait, Cycling, And Elliptical Training, Greg Orekhov

Master's Theses

Transtibial amputees are at increased risk of contralateral hip and knee joint osteoarthritis, likely due to abnormal biomechanics. Biomechanical challenges exist for transtibial amputees in gait and cycling; particularly, asymmetry in ground/pedal reaction forces and joint kinetics is well documented and state-of-the-art passive and powered prostheses do not fully restore natural biomechanics. Elliptical training has not been studied as a potential exercise for rehabilitation, nor have any studies been published that compare joint kinematics and kinetics and ground/pedal reaction forces for the same group of transtibial amputees in gait, cycling, and elliptical training. The hypothesis was that hip and knee …

Inverse Dynamic Analysis Of Acl Reconstructed Knee Joint Biomechanics During Gait And Cycling Using Opensim, Megan V. Pottinger

Master's Theses

ACL (anterior cruciate ligament) injuries of the knee joint alter biomechanics and may cause abnormal loading conditions that place patients at a higher risk of developing osteoarthritis (OA). There are multiple types of ACL reconstruction (ACLR), but all types aim to restore anterior tibial translation and internal tibial rotation following surgery. Analyzing knee joint contact loads provide insight into the loading conditions following ACLR that may contribute to the long-term development of OA. Ten ACLR subjects, who underwent the same reconstruction, performed gait and cycling experiments while kinematic and kinetic data were collected. Inverse dynamic analyses were performed on processed …

The Development Of A Temporomandibular Force Simulator To Study Craniofacial Strain In-Vitro, Kenneth Kc Ip

Electronic Thesis and Dissertation Repository

An in-vitro musculoskeletal loading simulator was developed to replicate the internal forces of mastication, and then employed in a comparison of clinically relevant facial fracture repairs. Muscle forces are simulated by pneumatic pistons via 3D printed mounts that are reverse-engineered from CT scan to match muscle attachment sites, which are adhered to bone in order to simulate native stress distributions. Bite force and bone strain pattern of the craniofacial structure under load were measured using a force sensor and strain gauges respectively. In a series of five fresh-frozen cadaveric heads, it was found that strain patterns of the craniofacial structure …

Examining Reverse Total Shoulder Arthroplasty Baseplate Fixation In Patients With E2-Type Glenoid Erosion, Matthew D. Mahaffy

Electronic Thesis and Dissertation Repository

Superior glenoid erosion of the shoulder joint is a result of humeral subluxation caused by rotator cuff tears, and can be addressed using implants, specifically reverse total shoulder arthroplasty. This thesis examined the regional variations of bone present in superiorly eroded glenoids, established a baseline for regular RTSA baseplate fixation in patients with this defect, and compared the effect of geometric baseplate differences on implant fixation. The superiorly eroded glenoids demonstrated similar regional bone density variations as normal glenoids, and the superior and inferior regions of the glenoid demonstrated the densest and least dense cancellous bone, respectively. These regions also …

Feasibility Of Using An Equilibrium Point Strategy To Control Reaching Movements Of Paralyzed Arms With Functional Electrical Stimulation, Matthew Huffman

ETD Archive

Functional electrical stimulation (FES) is a technology capable of improving the quality of life for those with the loss of limb movement related to spinal cord injuries. Individuals with high-level tetraplegia, in particular, have lost all movement capabilities below the neck. FES has shown promise in bypassing spinal cord damage by sending electrical impulses directly to a nerve or muscle to trigger a desired function. Despite advancements in FES, full-arm reaching motions have not been achieved, leaving patients unable to perform fundamental tasks such as eating and grooming. To overcome the inability in current FES models to achieve multi-joint coordination, …

Characterizing The Effects Of High-Intensity Exercise On Balance And Gait Under Dual-Task Conditions In Parkinson’S Disease, El Iva Baron

ETD Archive

Parkinson’s disease (PD) is a neurodegenerative disorder, characterized by four cardinal motor symptoms including bradykinesia, tremor, rigidity, and postural instability, and non-motor symptoms including cognitive impairment. Daily activities, such as walking and maintaining balance, are impacted due to impairments in motor function, and are further exacerbated with the addition of cognitive loading, or dual-tasking (DT). High-intensity exercise has demonstrated centrally-mediated improvements of PD symptoms, with additional positive effects on overall health. The goal of this project was to identify changes in dynamic balance recovery and gait function under conditions with and without increased cognitive load after a high-intensity exercise intervention …

Neuromuscular Reflex Control For Prostheses And Exoskeletons, Sandra K. Hnat

ETD Archive

Recent powered lower-limb prosthetic and orthotic (P/O) devices aim to restore legged mobility for persons with an amputation or spinal cord injury. Though various control strategies have been proposed for these devices, specifically finite-state impedance controllers, natural gait mechanics are not usually achieved. The goal of this project was to invent a biologically-inspired controller for powered P/O devices. We hypothesize that a more muscle-like actuation system, including spinal reflexes and vestibular feedback, can achieve able-bodied walking and also respond to outside perturbations. The outputs of the Virtual Muscle Reflex (VMR) controller are joint torque commands, sent to the electric motors …

Predictive Simulations Of Gait And Their Application In Prosthesis Design, Anne D. Koelewijin

ETD Archive

Predictive simulations predict human gait by solving a trajectory optimization problem by minimizing energy expenditure. These simulations could predict the effect of a prosthesis on gait before its use. This dissertation has four aims, to show the application of predictive simulations in prosthesis design and to improve the quality of predictive simulations. Aim 1 was to explain joint moment asymmetry in the knee and hip in gait of persons with a transtibial amputation (TTA gait). Predictive simulations showed that an asymmetric gait required less effort. However, a small effort increase yielded a gait with increased joint moment symmetry and reduced …

The Effect Of Tackling Training On Head Accelerations In Youth American Football, Eric Schussler, Richard J. Jagacinski, Susan E. White, Ajit M. Chaudhari, John A. Buford, James A. Onate

Rehabilitation Sciences Faculty Publications

Background: Many organizations have introduced frameworks to reduce the incidence of football related concussions through proper equipment fitting, coach education, and alteration of tackling technique.

Purpose: The purpose of this study was to examine the effects of training in a vertical, head up tackling style on the number of head accelerations experienced while tackling in a controlled laboratory situation. The authors hypothesized that training in a head up tackling technique would reduce the severity of head acceleration experienced by participants.

Design: Controlled Laboratory Study.

Methods: Twenty-four participants (11.5 ± 0.6 years old, 60.5 ± 2.2 in, 110 ± 18.4 lbs.) …

Predictive Modeling Of Hip Dislocation: Assessment Of Surgical And Patient Factors To Reduce The Occurrence Of Hip Instability And Adverse Clinical Outcomes, Daniel N. Huff

Electronic Theses and Dissertations

Instability and dislocation remain leading indications for revision of primary Total Hip Arthroplasty (THA). Many studies have addressed the links between implant design and propensity for dislocation, however a comprehensive review of the ability of modern THA constructs to protect against joint instability is needed.

Accordingly, the objective of this study is to provide objective data about THA risks to be considered in the treatment algorithm to protect against adverse joint loading conditions and joint instability. Adverse loading conditions were assessed in a population of activities of daily living using data from telemetric hip implant representation in an FE simulation …

Design And Analysis Of A 3d-Printed, Thermoplastic Elastomer (Tpe) Spring Element For Use In Corrective Hand Orthotics, Kevin Thomas Richardson

Theses and Dissertations--Mechanical Engineering

This thesis proposes an algorithm that determine the geometry of 3D-printed, custom-designed spring element bands made of thermoplastic elastomer (TPE) for use in a wearable orthotic device to aid in the physical therapy of a human hand exhibiting spasticity after stroke. Each finger of the hand is modeled as a mechanical system consisting of a triple-rod pendulum with nonlinear stiffness at each joint and forces applied at the attachment point of each flexor muscle. The system is assumed quasi-static, which leads to a torque balance between the flexor tendons in the hand, joint stiffness and the design force applied to …

The Effect Of Radial And Ulnar Length Change On Distal Forearm Loading, Ahaoiza D. Isa

Electronic Thesis and Dissertation Repository

The effect of distal radial and ulnar length change on forearm bone loading is not well understood during simulated dynamic wrist loading. This thesis presents two studies which investigate the effect of these length changes on distal forearm loading under simulated dynamic wrist motion. The first study investigates the effect of radial length change on axial loading at the distal radius and ulna and relationship between ulnar variance and distal forearm loading. The complex variation in axial loads in the distal radius and during length change and dynamic wrist motion were studied and discussed. There was no correlation between native …

Biomechanical Testing Of An Exercise For Strengthening The Proximal Femur., Alyssa Osbourne

Electronic Theses and Dissertations

Based on the principles of cutting edge bone remodeling research, a unique therapeutic exercise device was designed specifically to improve bone quality at the most critical location of the proximal femur prone to fracture: the superior-lateral femoral neck where the fracture first initiates during a fall. The exercise/device is intended to work by inducing enough strain in the bone to stimulate the body’s natural bone remodeling mechanisms to increase bone density in the proximal femur and consequently prevent a fracture from arising if a fall to the side does occur.

In order to test the proposed exercise, experiments simulating the …

The Effect Of Twist On The Mechanical Properties Of The Intervertebral Disc, Maxine Harvey-Burgess

Theses and Dissertations (Comprehensive)

Introduction: Intervertebral disc (IVD) herniation is a common injury to the IVD and a frequent source of low back pain. IVD herniation occurs when the nucleus pulposus migrates through both the inter- and intralamellar matrices of the annulus fibrosus (AF). There are a number of mechanical risk factors associated with herniation, including repetitive flexion and twist. In vivo, twist combined with repetitive flexion has been associated with increased experience of low back pain and herniation. Additionally, in vitro, when repetitive flexion is combined with twist, IVD herniation occurs more easily than repetitive flexion alone. However, the mechanisms behind …

Specimen-Specific Natural, Pathological, And Implanted Knee Mechanics Using Finite Element Modeling, Azhar Akber Ali

Electronic Theses and Dissertations

There is an increasing incidence of knee pain and injury among the population, and increasing demand for higher knee function in total knee replacement designs. As a result, clinicians and implant manufacturers are interested in improving patient outcomes, and evaluation of knee mechanics is essential for better diagnosis and repair of knee pathologies. Common knee pathologies include osteoarthritis (degradation of the articulating surfaces), patellofemoral pain, and cruciate ligament injury and/or rupture. The complex behavior of knee motion presents unique challenges in the diagnosis of knee pathology and restoration of healthy knee function. Quantifying knee mechanics is essential for developing successful …

Development Of Standard Criteria To Evaluate The Effectiveness Of Helmets At Decreasing The Risk Of Concussions, Daniel Y. Shyu, Goutham N. Sankaran, Kevin G. Mciver, Nicolas Leiva, Eric A. Nauman

The Summer Undergraduate Research Fellowship (SURF) Symposium

In many sports, such as American football, accumulations of mild traumatic brain injuries have been suggested as a possible link to neurodegeneration and future mental disorders. With head impacts occurring at all levels of competition and in different sports, it is critical to develop an accurate method for quantifying the effects of head impacts and determining the efficacy of helmets. This study examines the derivation of different dimensionless numbers and ascertains the critical factors needed to predict the effects of head impacts, specifically the resulting accelerations from an impact. Given a known force of impact, parameters such as peak translation …

Ball Pressure Correlations With Peak Impact Force And The Potential For Cumulative Mtbi When Heading A Soccer Ball, Nicolas Leiva, Daniel Y. Shyu, Josh Auger, Eric Nauman

The Summer Undergraduate Research Fellowship (SURF) Symposium

Soccer is a unique sport in which athletes use their heads as tools for gameplay, which may ultimately cause cumulative traumatic brain injuries. Due to rising popularity of soccer in the United States alongside the increased occurrence of CTE and mTBI in other contact sports, there is a growing concern over how to keep the repetitive forces caused by heading, as low as possible. Different variables that can affect the peak force felt when heading a soccer ball can be simulated and compared with in-game data, however, this has never been properly tested before. In the present study two size …

The Effects Of Obesity On Resultant Knee Joint Loads For Gait And Cycling, Juan Gutierrez-Franco

Master's Theses

Osteoarthritis (OA) is a degenerative disease of cartilage and bone tissue and the most common form of arthritis, accounting for US$ 10.5 billion in hospital charges in 2006. Obesity (OB) has been linked to increased risk of developing knee OA due to increased knee joint loads and varus-valgus misalignment. Walking is recommended as a weight-loss activity but it may increase risk of knee OA as OB gait increases knee loads. Cycling has been proposed as an alternative weight-loss measure, however, lack of studies comparing normal weight (NW) and OB subjects in cycling and gait hinder identification of exercises that may …

Wheelchair Fatigue Reducer, Aaron Miller, Dennis Andre Norfleet

Chancellor’s Honors Program Projects

No abstract provided.

Markerless Radiostereogammetry Of The Shoulder Joint In Humans: Comparisons Of Scapulohumeral Kinematics Between Individuals With Healthy And Supraspinatus-Impaired Shoulders, Ashley N. Hannon

Electronic Thesis and Dissertation Repository

The purpose of this collection of studies was to further develop the knowledge of shoulder motion in order to better understand joint function through direct measurement of 3D scapulohumeral joint kinematics using a technique of high accuracy. Markerless, bi-planar fluoroscopic radiostereometric analysis using a generic shoulder model was developed in this thesis, reducing the amount of radiation exposure to subjects. The studies compared kinematic data of the scapulohumeral joint in six degrees of freedom with a precise, in-vivo measuring technique. Data were collected on young and older healthy individuals, individuals with a torn supraspinatus and post-surgical intervention.

Although this generic …

Investigation Of The Inherent Chemical, Structural, And Mechanical Attributes Of Bio-Engineered Composites Found In Nature: Alligator Gar’S Exoskeleton Fish Scales, Wayne Derald Hodo

Graduate Theses and Dissertations

The U.S. Army has determined a huge cost savings of up to 51% can be accomplished by reducing the gross vehicle weight, for their personnel carrier, by 33%. To cut cost, composite materials are needed. Man-made composites can have superior material properties (high-strength, high-fracture toughness, and lightweight), but they are prone to delamination at the glued-layered interface. In contrast, fish scale is a natural composite that has the same material properties and, additionally, tend not to delaminate.

The focus of this study was to learn how nature integrates hard and soft materials at each length scale to form a layered …

Effect Of Hemiarthroplasty Implant Contact Geometry And Material On Early Cartilage Wear, Alana Khayat

Electronic Thesis and Dissertation Repository

Hemiarthroplasty is a minimally invasive, cost-effective alternative to total arthroplasty in joints of the upper limb. Though these procedures reduce patient morbidity while restoring joint kinematics, their longevity is limited by wear of the adjacent cartilage. This work investigates the roles of contact geometry and implant stiffness on cartilage wear with the aim of elucidating the mechanics that contribute to cartilage damage. An in vitro study examined the influence of implant geometry on cartilage wear using a pin-on-plate wear simulator. A significant decrease in volumetric wear was observed as contact area increased, which suggests that maximizing contact area should be …

A Finite Element Analysis On The Viscoelasticity Of Postmenopausal Compact Bone Utilizing A Complex Collagen D-Spacing Model, Austin C. Cummings

Master's Theses

The nanoscale dimension known as D-spacing describes the staggering of collagen molecules, which are fundamental to the biphasic makeup of bone tissue. This dimension was long assumed to be constant, but recent studies have shown that the periodicity of collagen is variable. Given that the arrangement of collagen molecules is closely related to the degree of bone mineralization, recent studies have begun to look at D-spacing as a potential factor in the ongoing effort to battle postmenopausal osteoporosis. The theoretical models presented by previous studies have only opted to model a single collagen-hydroxyapatite period, so the creation of an intricate …

Du01, Center For Orthopaedic Biomechanics, Michael D. Harris, Phd, Kevin Shelburne, Phd

Natural Knee Data

No abstract provided.

Du06, Center For Orthopaedic Biomechanics, Michael D. Harris, Phd, Kevin Shelburne, Phd

Natural Knee Data

No abstract provided.

Du05, Center For Orthopaedic Biomechanics, Michael D. Harris, Phd, Kevin Shelburne, Phd

Natural Knee Data

No abstract provided.

Du04, Center For Orthopaedic Biomechanics, Michael D. Harris, Phd, Kevin Shelburne, Phd

Natural Knee Data

No abstract provided.

Du03, Center For Orthopaedic Biomechanics, Michael D. Harris, Phd, Kevin Shelburne, Phd

Natural Knee Data

No abstract provided.

Du02, Center For Orthopaedic Biomechanics, Michael D. Harris, Phd, Kevin Shelburne, Phd

Natural Knee Data

No abstract provided.