Mechanical Engineering Commons^™

Characterizing Tkr Biomechanics Using A Novel Muscle-Driven Joint Motion Simulator, Alexandre Galley

Electronic Thesis and Dissertation Repository

Total knee replacement (TKR) is the end-stage treatment for severe cases of knee osteoarthritis (OA). Despite its success in alleviating pain and restoring mobility to the knee, patient satisfaction rates post-TKR are still lower than other common joint replacement surgeries. Knee kinematics and stability, key determinants of successful TKR, are assessed intraoperatively and tracked post-operatively in in vivo clinical studies. However, the persistently low satisfaction rates suggest that more sophisticated pre-clinical testing methods are needed to better understand the biomechanics of these implants early in their development. During pre-clinical testing of TKR implants, different joint motion simulators are used for …

Understanding Real-World And Laboratory Traumatic Brain Injury (Tbi) Using The Computational Model With Brain Functional Regions, Kewei Bian

Electronic Thesis and Dissertation Repository

Traumatic brain injury (TBI), including mild traumatic brain injury (mTBI) or concussion, is a severe health concern. Many symptoms, such as headache, dizziness, and working memory deficits, are reported to be related to the dysfunction of brain functional regions, but the underlying mechanism remains unknown. Hence, further developing tools and analyses to understand brain dysfunction for better TBI prevention are important. Additionally, such analyses should be conducted for both real-world TBI cases and laboratory studies, as TBI data can only be collected from the real world, and prevention measures, such as helmets, are developed and evaluated in the lab. Accordingly, …

Mechanical Response Of The Craniofacial Skeleton To Subfracture Impacts In The Time And Frequency Domains, Paige Merko

Electronic Thesis and Dissertation Repository

Resonant frequencies have been suggested as a mechanism of brain injury since these vibrations can transfer energy into the brain. Study of the vibrational response of the craniofacial skeleton to impact is limited in literature. In this research, four cadaver specimens were impacted at five locations on the craniofacial skeleton. The mechanical response to each impact was compared in the time and frequency domains. Impacts to the maxilla and its associated soft tissues tended to be attenuated, while impacts to the cranial vault, specifically to the occipital, produced the most severe response. Results suggest that the facial skeleton and its …

Using Statistics, Computational Modelling And Artificial Intelligence Methods To Study And Strengthen The Link Between Kinematic Impacts And Mtbis, Andrew Luke Mcconnell Patterson

Electronic Thesis and Dissertation Repository

Mild traumatic brain injuries (mTBIs) are frequently occurring, yet poorly understood, injuries in sports (e.g., ice hockey) and other physical recreation activities where head impacts occur. Helmets are essential pieces of equipment used to protect participants’ heads from mTBIs. Evaluating the performance of helmets to prevent mTBIs using simulations on anatomically accurate computational head finite element models is critically important for advancing the development of safer helmets. Advancing the level of detail in, and access to, such models, and their continued validation through state-of-the-art brain imaging methods and traditional head injury assessment procedures, is also essential to improve safety. The …

Development Of A Two-Axis Cyclic Loading Device For Mechanical Testing Of Glenoid Component Fixation, Cintya Tavares

Electronic Thesis and Dissertation Repository

The fundamental mechanism of aseptic glenoid component loosening, the rocking horse phenomenon, is a reaction to glenohumeral articular forces that are not centered on the component. While glenoid component loosening remains a problem, the underlying mechanisms that lead to fixation failure at the bone-component contact remain controversial. Several studies employing the ASTM F2028 technique have successfully recreated the rocking horse effect. However, no obvious strategy to decrease component loosening has been presented. This thesis investigates the behavior of forces that lead to component loosening on cyclically loaded components using three different protocols and testing apparatuses—a Stewart Platform, a cyclic loading …

The Design And Evaluation Of A Subacromial Implant In Restoring Normal Glenohumeral Joint Stability In The Presence Of A Massive Irreparable Rotator Cuff Tear, Cole T. Fleet

Electronic Thesis and Dissertation Repository

Massive irreparable rotator cuff tears are a common cause of pain and disability. Several different treatment options are available for this pathology; however, these treatments have been associated with poor clinical outcomes when used to treat younger (<65 years), more active patients. The purpose of this thesis was to design and evaluate a subacromial implant in its ability to restore normal glenohumeral stability and range of motion. The implant was created as a modular device, which captured different implant thicknesses (5mm and 8mm) and constraints (high and low) within its design. In-vitro testing compared the ability of these implants to restore normal shoulder biomechanics. The results indicated the 5mm high constraint implant to be the most effective in restoring normal joint position. Furthermore, range of motion increased when the implant was paired with a tuberoplasty procedure. These results suggest this implant may be advantageous in treating younger patients.

Motion And Crosslinked Polyethylene Wear In Reverse Total Shoulder Arthroplasty, Christopher Millward

Electronic Thesis and Dissertation Repository

The reverse total shoulder arthroplasty (RTSA) has quickly grown to become the most commonly used shoulder arthroplasty design; however, reports have shown evidence of RTSA failures related to polyethylene wear and damage. Therefore, the present work investigated the wear of crosslinked polyethylene (XLPE) in environments similar to that of an in vivo RTSA. Additionally, a computational model was developed based on a previous study of the shoulder motions obtained from a selection of typical patients with RTSA. This model quantified the amount of glenohumeral motion that an RTSA may be subjected to in vivo and provided an approximate value for …

To Develop A Clinically Friendly Multi-Segment Kinematic And Kinetic Foot Model And Test It On Pre-/Post-Hto Patients With Medial Knee Osteoarthritis And Knee Varus, Songlin Zhu

Electronic Thesis and Dissertation Repository

This study aims to develop a clinically useful multi-segment foot model that will enable the analysis of foot kinematics and kinetics in an optical motion capture laboratory setting. This study will also test the new multi-segment foot model on patients with knee osteoarthritis and varus knee alignment that is corrected by high tibial osteotomy (HTO). The multi-segment foot model divides the foot into four functional segments: the hindfoot, midfoot, forefoot and hallux. An X-Z-Y-Cardan angle rotation convention was used to determine intersegmental dorsi/plantar flexion, inversion/eversion, and internal/external rotation. Joint moments, joint powers and medio-longitudinal arch (MLA) height/length ratio were also …

The Role Of Transient Vibration Of The Skull On Concussion, Rodrigo Dalvit Carvalho Da Silva

Electronic Thesis and Dissertation Repository

Concussion is a traumatic brain injury usually caused by a direct or indirect blow to the head that affects brain function. The maximum mechanical impedance of the brain tissue occurs at 450±50 Hz and may be affected by the skull resonant frequencies. After an impact to the head, vibration resonance of the skull damages the underlying cortex. The skull deforms and vibrates, like a bell for 3 to 5 milliseconds, bruising the cortex. Furthermore, the deceleration forces the frontal and temporal cortex against the skull, eliminating a layer of cerebrospinal fluid. When the skull vibrates, the force spreads directly to …

The Influence Of Frontal And Axial Plane Deformities On Contact Mechanics During Squatting: A Finite Element Study, Yidan Xu

Electronic Thesis and Dissertation Repository

Knee Osteoarthritis (KOA) is a degenerative joint disease and a leading cause of disability worldwide. Lower limb malalignment was a risky factor leading to KOA, altering the load distributions. This study aimed to study the influence of knee deformities on knee contact mechanics and knee kinematics during squatting. A full-leg squat FE model was developed based on general open-source models and validated with in vivo studies to investigate the outputs under frontal malalignment (valgus 8° to varus 8°) and axial malalignment (miserable malalignment 30°). As a result, Varus-aligned and miserable aligned models increased medial tibiofemoral force and lateral patellar contact …

Significance Of The Vehicle Front Design And Gait Postures On Traumatic Brain Injuries Sustained By Different Pedestrian Populations During Car-To-Pedestrian Collisions (Cpcs) - A Computational Approach, Thava Kalishwara Kumar Gunasekaran

Electronic Thesis and Dissertation Repository

With the increasing prevalence of traumatic brain injuries (TBIs) in road traffic accidents (RTAs), it was identified that the shape of the vehicle's front end and pedestrian postures prior to impact significantly influence pedestrian head injuries. However, the effect of vehicle front shape parameters and gait postures on TBIs sustained in car-to-pedestrian collisions (CPCs) has yet to be quantified. This study used a computational approach to analyze the effect of vehicle shape parameters and pedestrian gait postures on pedestrian TBI risks across a diverse pedestrian population with varying body sizes. Our findings indicate that vehicle shape parameter such as BLEH …

Significance Of The Neck In Concussive Head Impacts – A Computational Approach, Sakib Ul Islam

Electronic Thesis and Dissertation Repository

With the rising concern of concussions in contact sports, it is believed that cervical muscles could play a vital role in attenuating force to the head. However, the biomechanical effect of cervical muscles on head and brain response is not clearly understood. This study adopted a finite element head and neck model to replicate football impacts under various loading conditions to study the effect of neck muscles on head kinematics. Our results indicate that neck muscles have the highest amount of internal energy absorption in early impact, particularly at the time when peak head kinematics develop. Both deep and superficial …

A Multi-Level Mechanical Assessment Of The Shoulder Coupled With Evaluation Of Upper Extremity Predictive Finite Element Models, Jonathan Kusins

Electronic Thesis and Dissertation Repository

Research involving joint mechanics is typically conducted at the macroscopic level. However, joints and joint replacements often fail because load transfer at the microscopic level is not well understood. This gap in knowledge reduces our ability to preoperatively predict patient outcomes and assess irreversible failure modes for a variety of surgical interventions prior to clinical adoption. The present work aims to advance full-field experimental measurement techniques applied to better understand the internal load transfer of the human shoulder joint by simultaneously combining mechanical testing protocols, microCT imaging, and digital volume correlation (DVC) methods.

A CT-compatible loading apparatus was fabricated to …

Biomaterial For Cervical Intervertebral Disc Prosthesis, Helium Mak

Electronic Thesis and Dissertation Repository

Recent long-term follow-up studies have shown that the cervical disc arthroplasty treatment have potentials in developing surrounding heterotopic ossification (HO). While its cause requires further investigation, this thesis has hypothesized that it may be the result of the continual remodeling of the injured vertebrae caused by the prostheses with smaller footprints introducing abnormal stresses. The research objective of this thesis is to develop a new prosthesis material that can be molded into any form conforming to the size and shape of the end-plates of the affected patient vertebrae. For prototype development, a composite material consisting of 10wt% polyvinyl alcohol cryogel …

Investigation Of Small Remotely Piloted Aircraft System (Srpas) To Human Head Impact, Yuhu Weng

Electronic Thesis and Dissertation Repository

Small remotely piloted aircraft system (sRPAS) to ground human head impact could cause injuries to the public. Skull fractures and brain injuries have been observed in sRPAS-related impacts, which varied in angles, locations and velocities. This study developed a representative quadcopter sRPAS finite element model and incorporated it with THUMS ver 4.02 50^th percentile male and 5^th percentile small female models to simulate sRPAS to human head impacts. The simulations were validated with cadaver experiments. The common injury metrics such as head injury criteria (HIC) and brain injury criterion (BrIC) were correlated with head injury-related responses such as …

Developing Multi-Species Brain-Strain-Based Scaling Law Using Finite Element Analysis., Xingyu Liu

Electronic Thesis and Dissertation Repository

To better understand traumatic brain injury (TBI), various laboratory animal experiments have been developed. However, there lacks an effective scaling to connect animal TBI models with human brain injuries. With the help of the finite element (FE) model, brain mechanical responses such as strains can be predicted, and hence can serve as a parameter to facilitate animal to human scaling, as these tissue-level strains directly link to neuronal damage. In this thesis, first, a comprehensive comparison of brain strains between animal TBI models and human TBI cases was conducted. Then, a brain-strain-based scaling law between mouse and human was developed, …

Development Of A Wireless Telemetry Load And Displacement Sensor For Orthopaedic Applications, William Anderson

Electronic Thesis and Dissertation Repository

Due to sensor size and supporting circuitry, in vivo load and deformation measurements are currently restricted to applications within larger orthopaedic implants. The objective of this thesis is to repurpose a commercially available low-power, miniature, wireless, telemetric, tire-pressure sensor (FXTH87) to measure load and deformation for future use in biomechanical applications. The capacitive transducer membrane of the FXTH87 was modified, and a relationship was reported between applied compressive deformation and sensor signal value. The sensor package was embedded within a deformable enclosure to illustrate potential applications of the sensor for monitoring load. Finite element analysis was an effective tool to …

Biomechanical Analysis Of Commotio Cordis In Children's Baseball - A Computational Approach, Grant J. Dickey

Electronic Thesis and Dissertation Repository

Commotio cordis is the second leading cause of cardiac death in young athletes. This rare sudden-death mechanism most commonly affects young children playing baseball. It is caused by impacts to the chest during the repolarization phase of the cardiac cycle, which causes the heart to go into ventricular fibrillation, often leading to death. This study adopted the detailed and validated CHARM-10 child finite element model to replicate commotio cordis instances by simulating baseball impacts to the chest. New commotio cordis injury metrics were developed to create a more accurate prediction for chest protector effectiveness. The conventionally used injury metrics for …

The Effect Of Humeral Short Stem Positioning, Humeral Head Contact, And Head Positioning On Bone Stress Following Total Shoulder Arthroplasty, Amir Tavakoli

Electronic Thesis and Dissertation Repository

Uncemented humeral stems cause stress shielding which result in bone resorption when used in total shoulder arthroplasty (TSA). Shorter length stems show a decrease in stress shielding, however the effect of humeral short stem positioning and humeral head contact and positioning on bone stress is currently not known, hence CT-based tools and Finite Element (FE) methods are used to quantify the effects of the mentioned variables on bone stresses after TSA.

Eight male cadaveric humeri were virtually constructed from computed tomography (CT) data, with a generic short humeral short stem as the implant.

The results of this work show that …

An Investigation On The Influences Of Radial Head Hemiarthroplasty Stem Fixation Techniques On Articular Mechanics, Jakub Szmit

Electronic Thesis and Dissertation Repository

Radial head hemiarthroplasty design has been extensively studied with a focus on utilizing the geometrical characteristics of the native radial dish as a guide of implant placement and design. Although implant design has been studied, optimal radial head implant fixation technique remains unknown. This thesis focused on the effect of stem fit on radiocapitellar contact mechanics, using both finite element and experimental bench-top approaches. Additionally, investigation into the impact of varus/valgus malalignment of the radial head in both the native state and following hemiarthroplasty was conducted. It was found that loose fitting a smooth stem axisymmetric radial head implant through …

A Computational Investigation Into Acromial Fractures After Reverse Total Shoulder Arthroplasty, Jason Lockhart

Electronic Thesis and Dissertation Repository

Acromial fractures are a debilitating complication following reverse total shoulder arthroplasty (RTSA). The purpose of this work is to (1) improve the current state of FE bone stress estimates after RTSA and to investigate the effects of (2) plane of elevation, (3) hand loads, and (4) baseplate screw position on scapular spine stress. The FE method used was validated against an in-vitro strain gauge based experiment and found to be accurate in the prediction of stress increases and decreases after RTSA. The coronal plane of elevation was found to increase scapular spine stress compared to more central planes of elevation. …

Lower Stiffness Orthopaedic Implants For Hemiarthroplasty, Carolyn Berkmortel

Electronic Thesis and Dissertation Repository

One of the main drawbacks of hemiarthroplasty is that it involves the articulation of a foreign material against the native cartilage, and hence the native cartilage experiences accelerated wear. It is hypothesized that lowering the stiffness of hemiarthroplasty implants will decrease contact pressure and increase contact area, thus decrease wear. Lowering the stiffness was done using finite element analysis to lower the stiffness of the implant materials, and then to change the internal structure of the implants to increase their compliance. Structural changes produced no noticeable or favourable results, whereas material produced improved results for stiffnesses below a Young’s modulus …

Biomechanical Analysis Of Open-Skull High-Rate Traumatic Brain Injury Using Finite Element Mouse Brain Model, Lihong Lu

Electronic Thesis and Dissertation Repository

To better understand traumatic brain injury (TBI), it is necessary to correlate with injuries, which are observed from in vivo laboratory experiments, to brain mechanical responses, which can so far be best predicted by finite element (FE) models. Firstly, a previously validated FE model was improved to investigate the effect of repeated impacts and lateral movements on brain responses to ensure the accuracy and reproducibility of controlled cortical impact (CCI) across different labs. Then, a new FE mouse brain model with the detailed three-dimensional (3D), non-linear vasculature was developed to study how the vasculature affected brain response in CCI and …

A Heterogeneous Patient-Specific Biomechanical Model Of The Lung For Tumor Motion Compensation And Effective Lung Radiation Therapy Planning, Parya Jafari

Electronic Thesis and Dissertation Repository

Radiation therapy is a main component of treatment for many lung cancer patients. However, the respiratory motion can cause inaccuracies in radiation delivery that can lead to treatment complications. In addition, the radiation-induced damage to healthy tissue limits the effectiveness of radiation treatment. Motion management methods have been developed to increase the accuracy of radiation delivery, and functional avoidance treatment planning has emerged to help reduce the chances of radiation-induced toxicity. In this work, we have developed biomechanical model-based techniques for tumor motion estimation, as well as lung functional imaging. The proposed biomechanical model accurately estimates lung and tumor motion/deformation …

In Vitro Biomechanical Analyses Of The Pcl And Medial Ligaments Of The Human Knee, Alireza Moslemian

Electronic Thesis and Dissertation Repository

Previous studies have shown that surgical treatments of PCL injuries are not successful in all cases and there is room for improvement. The effectiveness of an isolated PCL reconstruction, in the setting of what actually is a multi-ligament injury, may be inadequate, and therefore the biomechanical contribution of other ligaments in a PCL-deficient knee need to be better understood.

A new apparatus was used to analyze the effect of medial ligaments transection on the kinematics of the PCL-deficient knee during simulated clinical tests and activities of daily living. We observed that the anterior translation of the medial side of the …

A Novel Method For In Vivo Evaluation Of Finger Kinematics For Analysis Of Activities Of Daily Living, Ahmed M. Tanashi

Electronic Thesis and Dissertation Repository

This thesis examines the development of a six degrees of freedom finger coordinate system that employs electromagnetic tracking to measure finger kinematics. Secondarily, this thesis validated the in vivo finger coordinate system, and is then used to examine range of motion in the fingers in patients with hand osteoarthritis. Lastly, this thesis examines the range of motion of individuals with and without hand arthritis during various activities of daily living, performed with and with joint protection program principles. This study presents a foundation for finger kinematic evaluation and describes a methodology that will be used for larger studies to be …

Investigating Grip Range Of Motion And Force Exerted By Individuals With And Without Hand Arthritis During Functional Tasks And While Swinging A Golf Club, Sara Frances Holland

Electronic Thesis and Dissertation Repository

Hand arthritis is the leading cause of disability in individuals over the age of 50; resulting in dysfunction and pain, making activities of daily living and recreational activities such as golf difficult. Few studies have been conducted on the biomechanical response of individuals with hand arthritis when performing functional activities. This research quantified hand grip movements and strength differences seen in individuals with hand arthritis. Using a video-based motion capture system (Dartfish), a grip limitation of 17.2% (maximum flexion), and 12.7% (maximum extension) was discovered. A wireless finger force measurement system (FingerTPS), was used to show that larger diameter, softer …

Virtual Reality Simulation Of Glenoid Reaming Procedure, Mohammadreza Faieghi

Electronic Thesis and Dissertation Repository

Glenoid reaming is a bone machining operation in Total Shoulder Arthroplasty (TSA) in which the glenoid bone is resurfaced to make intimate contact with implant undersurface. While this step is crucial for the longevity of TSA, many surgeons find it technically challenging. With the recent advances in Virtual Reality (VR) simulations, it has become possible to realistically replicate complicated operations without any need for patients or cadavers, and at the same time, provide quantitative feedback to improve surgeons' psycho-motor skills. In light of these advantages, the current thesis intends to develop tools and methods required for construction of a VR …

A Composite Material-Based Computational Model For Diaphragm Muscle Biomechanical Simulation, Brett Coelho

Electronic Thesis and Dissertation Repository

Lung cancer is the most common cause of cancer related death among both men and women. Radiation therapy is the most widely used treatment for this disease. Motion compensation for tumor movement is often clinically important and biomechanics-based motion models may provide the most robust method as they are based on the physics of motion. In this study, we aim to develop a patient specific biomechanical model that predicts the deformation field of the diaphragm muscle during respiration. The first part of the project involved developing an accurate and adaptable micro-to-macro mechanical approach for skeletal muscle tissue modelling for application …

An In-Silico Assessment Of Stemless Shoulder Arthroplasty: From Ct To Predicted Bone Response, Jacob M. Reeves

Electronic Thesis and Dissertation Repository

Despite the emergence of stemless humeral implants that utilize short fixation features to gain purchase solely in the metaphysis, the literature contains little information regardingthe morphology and mechanical properties of the humerus’ proximal trabecular-canal, and how stemless implants impact bone response. The present work employs in-silicotools, including CT-based and Finite Element (FE) methods, to define parameters that may influence stemless implant design.

The density and morphology of the proximal humerus were assessed using CT-derived point clouds of the trabecular-canal. Bone density was found to diminish 15-20mm beneath the humeral head resection and was greater peripherally. The depth, path and bounding …