Biomedical Engineering and Bioengineering Commons^™

Kinematic Analysis Of Gait And Deep Knee Flexion For Pre- And Post-Operative Total Knee Arthroplasty, Samantha Collins

Electronic Theses and Dissertations

Osteoarthritis (OA) is a form of arthritis that develops in the joint due to overuse and aging causing pain, discomfort, and disability. Total Knee Arthroplasty (TKA) is a surgical procedure performed when OA symptoms are severe with an estimated 600,000 patients in the United States currently receiving TKA. Studies have reported dissatisfaction of the knee for 14-39% of patients. This study collected knee kinematics before and after surgery using stereo radiography for precise measurement of gait and deep knee flexion activities. Results showed healthy knee kinematics were not restored and no significant changes could be seen from OA kinematics in …

Exploration Of Motion Capture System To Investigate Human Shoulder Kinematics, Ola Alsaadi

Electronic Theses and Dissertations

The glenohumeral joint (GH) is commonly conceptualized as a ball-and-socket joint [1], and its center of rotation (COR) is presumed to coincide with the geometric center of the medial-superior region of the humeral head [2]. Recent research has endorsed improvements in COR estimation through invasive and noninvasive techniques, including cadaver studies, stereophotogrammetry, and motion capture (MOCAP) systems. Despite increased interest in wearable technology within human movement analysis, the problem of COR estimation employing MOCAP systems and its validation against bi-planar fluoroscopy remains relatively unexplored.

This study employed a marker-based MOCAP system to compare the accuracy, error, and precision of three …

Computational Methodology For Generating Patient-Specific Soft Tissue Representations, Ahilan Anantha Krishnan

Electronic Theses and Dissertations

This dissertation focused on modeling specimen-specific soft tissue structures in the context of joint replacement surgery. The research addressed four key aspects. The first study involved developing a workflow for creating finite element models of the hip capsule to replicate its torque-rotational response. Experimental data from ten cadaveric hips were used to calibrate the models, resulting in improved accuracy and relevance for surgical planning and implant design. The second study tackled the challenge of expediting the calibration of mechanical properties of the hip capsule to match patient-specific laxities. A statistical shape function model was proposed to generate patient-specific finite element …

Digital Twins Of The Living Knee: From Measurements To Model, Thor Erik Andreassen

Electronic Theses and Dissertations

Modern medicine has dramatically improved the lives of many. In orthopaedics, robotic surgery has given clinicians superior accuracy when performing interventions over conventional methods. Nevertheless, while these and many other methods are available to ensure treatments are performed successfully, far fewer methods exist to predict the proper treatment option for a given person. Clinicians are forced to categorize individuals, choosing the best treatment on “average.” However, many individuals differ significantly from the “average” person, for which many of these treatments are designed. Going forward, a method of testing, evaluating, and predicting different treatment options' short- and long-term effects on an …

Hemodynamic Assessment Of Y-Incision Aortic Root Enlargement Using Computational Simulations, Astitwa Ghimire

Electronic Theses and Dissertations

The Yang procedure is a new aortic root enlargement technique used to enlarge the aortic annulus by multiple valve sizes. The procedure prevents patient prosthesis mismatch and establishes a viable platform for future valve-in-valve implantation. This study used the Yang procedure to investigate the hemodynamics in the aortic root and bioprosthetic valve regions after aortic root enlargement. Results indicate the velocity magnitude at the sinus regions of a patient who underwent the Yang procedure was slower, indicating risks of flow stasis and thrombosis. Simulation results denote computational models can be created for optimization of surgical procedures.

A Virtual Method For Establishing Femoral Stem Position In Total Hip Arthroplasty, Samuel Mattei

Electronic Theses and Dissertations

Total hip arthroplasty (THA) is one of the most successful orthopedic surgeries performed, in which the hip joint is reconstructed to improve functionality and decrease pain in the joint. Despite the success of these procedures, femoral stem misalignment remains an area that influences THA success. The relationship between the femoral stem geometry and implanted femoral stem size and orientation is underreported due to limitations in the collection of radiographic data used for clinical pre-operative templating. Furthermore, the influence of anatomic measurements on the direction and size of the femoral stem are not considered due to imaging technique and difficulties associated …

Finite Element Modeling Of Patient-Specific Total Shoulder Arthroplasty, Ignacio Rivero Crespo

Electronic Theses and Dissertations

Total Shoulder Arthroplasty (TSA) is a surgical procedure designed to improve joint functionality by replacing the articulation between the humeral head and the glenoid fossa. Anatomic Total Shoulder Arthroplasty (aTSA) and Reverse Total Shoulder Arthroplasty (rTSA) are two types of replacement surgery to relieve pain and restore function of the shoulder. The overall goal of this study was to evaluate the effects of variation of certain patient and implant alignment parameters that may influence long-term outcomes of these surgical procedures, including kinematics, joint loads and contact mechanics. Computational models of six TSA subjects, three aTSA and three rTSA, were created …

Fully Coupled Fluid Structure Interaction Simulation Of Bioprosthetic Heart Valves: A Numerical And Experimental Analysis, Masod Sadipour

Electronic Theses and Dissertations

Aortic stenosis impacts approximately 7% of the global population. In the past decade, the role of computational modeling has been becoming considerably important in the design of BHVs. To obtain reliable solutions in computational modeling, it is essential to consider accurate properties of bioprosthetic heart valves (BHVs), such as density and mechanical properties. Previous computational studies assumed (bovine pericardium) BP used in BHVs density was comparable to water or blood. Yet, BP is subjected to multiple treatments like fixation and anti-calcification. In Chapter 2, I measured BP density and its effect on BHV leaflet stress and strain. In the second …

Patient Movement Monitoring Based On Imu And Deep Learning, Mohsen Sharifi Renani

Electronic Theses and Dissertations

Osteoarthritis (OA) is the leading cause of disability among the aging population in the United States and is frequently treated by replacing deteriorated joints with metal and plastic components. Developing better quantitative measures of movement quality to track patients longitudinally in their own homes would enable personalized treatment plans and hasten the advancement of promising new interventions. Wearable sensors and machine learning used to quantify patient movement could revolutionize the diagnosis and treatment of movement disorders. The purpose of this dissertation was to overcome technical challenges associated with the use of wearable sensors, specifically Inertial Measurement Units (IMUs), as a …

Improving Quantification Of Mitral Regurgitation Through Computational Fluid Dynamics And Ex Vivo Testing, Alexandra Flowers

Electronic Theses and Dissertations

Mitral regurgitation (MR) is a prominent cardiac disease affecting more than two million people in the United States alone. In order for patients to receive proper therapy, regurgitant volume must first be quantified. As there are an array of methods to do so, the proximal isovelocity surface area (PISA) method continues to be the most accurate and clinically used method. However, there are some difficulties obtaining the necessary measurements need for this when performing transthoracic echocardiography. This study aims to evaluate and present techniques that may be used to more accurately quantify regurgitation through ex vivo testing and computational fluid …

Pulmonary Valve Replacement, Mina Shafiei

Electronic Theses and Dissertations

Currently, transcatheter pulmonary valve replacement (TPVR) is a well-established alternative for surgical pulmonary valve replacement (SPVR) to treat pulmonary valve disorders in patients with prior congenital heart surgery. Edwards Sapien 3 valve is a bioprosthesis originally designed for the aortic position but has been used off-label in native right ventricular outflow tract (RVOT). It is currently under clinical trial to get food and drug administration (FDA) approval.

This study is a comparison of the performance of Sapien 3 with surgical bioprosthetics. The in vitro tests result showed Sapien 3 experiences less degree of opening and effective orifice area in pulmonic …

Structural And Hemodynamic Analysis Of Transcatheter Aortic Valves, Dong Qiu

Electronic Theses and Dissertations

The transcatheter aortic valve replacement (TAVR) procedure has become a well-established procedure for high, intermediate-risk, and low-risk patients. However, there is limited clinical data on the TAV's long-term durability, unlike SAV devices. Computational simulations can be an alternative way to evaluate the TAV devices. This dissertation aims to conduct structural and hemodynamic analyses on the TAV devices under different conditions using computational simulation approaches.

Initially, the impact of the bicuspid aortic valve on the TAV devices was evaluated. The result indicated that the CoreValve-like supra-annular self-expandable device was likely to have increased stress and strain on the leaflet when it …

An Investigation Into The Plate Fixation For Periprosthetic Femoral Fractures, Xiang Chen

Electronic Theses and Dissertations

Periprosthetic femoral fractures are the third most reason for reoperation after the total hip arthroplasty with an incident rate of approximately 6%. The Vancouver type B periprosthetic femoral fractures account for over 70% of all cases, while the sub-type B1 fracture (when the total hip stem is stable) has remained a clinical challenge due to incidences of severe complications after the standard plate-screw fixation. To seek biomechanically sound fixations for the Vancouver type B1 fracture, this dissertation developed a combined modeling and testing framework to investigate the efficacy of fixation for a Vancouver type B1 fracture using different construct lengths …

Revision Total Hip Femoral Stem Micromotion And Statistical Shape Modeling Of The Knee, William Fugit

Electronic Theses and Dissertations

The first purpose of this thesis was to compare the amount of micromotion seen in the femoral stem in a revision total hip arthroplasty between simple loading conditions and loading conditions derived from activities of daily living, through the use of experimental and computational methods. The amount of micromotion at the bone-implant interface was larger for activities of daily living, with ranges of 200μm more than the largest simple loading conditions. The second purpose of this thesis was to compare measurements of accuracy in a statistical shape model between individual bone and joint-level models, specifically for the knee. Using computational …

Contact Simulation For Evaluating Patient Specific Surgical Guide Stability, Vincent Nierste

Electronic Theses and Dissertations

This study proposes a novel computational method to quantify guide stability for Patient Specific Instrumentation (PSI) guides. A finite element contact model was used to analyze the final position of PSI guides on a femur across a range of loading parameters representing forces applied by a surgeon during operative use. Separate segmentation methods were used for the guide and bone geometry to represent differences between segmentation and actual patient geometry. The region of loading parameters over which the guide exhibited a consistent final position was measured and reported as Guide Stability Score. The model was verified using cadaver specimens for …

Correlating With Local Variation In Collagen Level And Mechanical Properties Of The Heart Tissues, Talayeh Tavangar

Electronic Theses and Dissertations

The determination of the myocardium's tissue properties is essential in constructing finite element (FE) models of the heart. To obtain accurate results, especially for functionally modeling the heart, we must determine the tissue properties in-vivo. The calculation of the heart tissue properties remains a challenging area as it is categorized as a heterogeneous, anisotropic, nonlinear soft tissue that undergoes large deformation. In this work, we tried to introduce and evaluated a finite element method to determine the mechanical properties of the cardiac tissue. The introduced method combined a finite element modeling with the experimentally obtained images from the left and …

Tibial Strains And Tray-Bone Micromotions After Total Knee Arthroplasty: Computational Studies Evaluating The Tibial Fixation, Huizhou Yang

Electronic Theses and Dissertations

Cemented and cementless fixation in total knee arthroplasty (TKA) have been successfully used for decades. As the number of younger and more active patients treated with TKA continues to increase, long-term implant survivorship is of increasing importance. One of the most common complications and hence the reason for revision is mechanical loosening (23.1% of all revised TKA). The loosening mechanisms have been proposed for different fixation types. For cemented fixation, bone remodeling after surgery is regulated by the changes in strain energy density (SED). The recruitment of osteoclasts and osteoblasts is controlled by SED-related signals. Insufficient stimuli can promote bone …

An Accuracy And Precision Analysis Of The Velys™ Robotic Assisted Solution For Total Knee Arthroplasty, Gary Doan

Electronic Theses and Dissertations

Total knee arthroplasty (TKA) is a procedure where the arthritic surfaces of the knee is removed and replaced with a combination of metal and polymer implants that recreates the joint line to restore function and quality of life. Implant alignment is important in the success of a TKA. Modern day conventional instrumentation can be cumbersome in the operating room and can be inaccurate when resecting bone and aligning implants. Patients with large errors in resections and implant orientation are more prone to experience mechanical failures with their TKA. Mechanical failures in primary TKA require revision surgeries which can lead to …

Accurate Measurement Of Healthy Joint Kinematics To Inform Diagnosis And Treatment, Vasiliki Kefala

Electronic Theses and Dissertations

The description of human motion has a primary importance in different scientific areas such as medicine, sports, physical therapy. Kinematics specifically studies pure motion without reference to the causes of motion such as forces. Understanding the kinematics of human movement is of critical importance in medicine and biology. Motion measure­ment can be used in order to to evaluate functional performance of limbs under normal and abnormal conditions. Kinematic knowledge is also important for diagnosis and surgi­cal treatment of joint disease and the design of implants to rehabilitate function. Accurate joint kinematics is essential to protect articular functionality. An alteration may …

Dislocation Mechanics Of Total Hip Arthroplasty: A Combined Experimental And Computational Analysis, Michael Scinto

Electronic Theses and Dissertations

While total hip arthroplasty is considered a successful procedure, dislocation remains a serious complication as recurrent dislocations may require additional surgeries. Knowledge on dislocation events as they occur in vivo are limited, therefore researchers rely on experimental and computational methods. A custom MATLAB script and an experimental procedure utilizing a six-degree of freedom actuator were developed to further understand how various surgical considerations affect dislocation mechanics in total hip arthroplasty. Computationally, it was determined that impingement free range of motion is limited during internal rotation in flexion and during external rotation in extension. Experimentally, our results suggest that the posterior …

Fluid Dynamics Characterization Of Transcatheter Aortic Valves, Mohammed Barakat

Electronic Theses and Dissertations

Aortic stenosis due to degenerative calcific aortic valvular disease is the most reason for aortic valve replacement in developed countries. Aortic stenosis affects up to 7% of the world population, and current clinical data indicate that the number of the affected people could be triple by 2050, due to population ageing and health lifestyle. Transcatheter aortic valve replacement (TAVR) was introduced as a minimal invasive treatment of severe aortic stenosis. Even though surgical aortic valve replacement (SAVR) is considered the golden standard treatment for severe aortic stenosis patients, TAVR showed equivalent or even superior outcome compare to SAVR. Currently, transcatheter …

Developing Machine Learning Algorithms For Behavior Recognition From Deep Brain Signals, Hosein Golshan Mojdehi

Electronic Theses and Dissertations

Parkinson’s disease (PD) is a neurodegenerative condition and movement disorder that appears with symptoms such as tremor, rigidity of muscles and slowness of movements. Deep brain stimulation (DBS) is an FDA-approved surgical therapy for essential tremor and PD. Despite the fact that DBS substantially alleviates the motor signs of PD, it can cause cognitive side effects and speech malfunction mainly due to the lack of adaptivity and optimality of the stimulation signal to the patients’ current state. A behavior-adapted closed-loop DBS system may reduce the side effects and power consumption by adjusting the stimulation parameters to patients’ need.

Behavior recognition …

Transcatheter Mitral Valve Replacement: Structural And Hemodynamic Analysis, Saba Ravaghi

Electronic Theses and Dissertations

Transcatheter mitral valve replacement (TMVR) is being developed to become a substitute therapy for surgery in prohibitive or high surgical risk patients to treat severe mitral regurgitation. A limited number of TMVR systems are under clinical evaluation. However, transcatheter mitral valve (TMV) long-term durability and hemodynamic performance is not known. TMV durability and hemodynamics must match with that of surgical bioprostheses for potential commercialization of TMVR. Experimental and computational approaches were used to find the leaflets’ three-dimensional anisotropic mechanical properties in a transcatheter Edwards SAPIEN 3 valve and a surgical Carpentier-Edwards PERIMOUNT Magna mitral valve and finite element (FE) simulations …

In Vivo Data Capture Using Hssr For Calibration Of Computational Models, Thor Erik Andreassen

Electronic Theses and Dissertations

Computational modeling is a vital tool for understanding and evaluating healthy and unhealthy function of the musculoskeletal aspects of the human body. However, the accuracy of the musculoskeletal models depends significantly on the accuracy of the input data used to calibrate various behavioral parameters of the model. To date, most computational models have been built using generic in vitro data, mostly because of a lack of accurate and meaningful datasets from in vivo testing. The next major step in computational modeling is to create subject-specific computational models using calibration data taken from in vivo testing. The overall goal was to …

Development Of A Clinical Marker-Less Motion Capture System For Patient Monitoring, Abigail Eustace

Electronic Theses and Dissertations

The ability to understand human movement is beneficial for deciding surgical procedures, tracking disease progression over time and helping with patient rehabilitation. The current gold-standard for collecting human movement is the use of 3-dimensional marker-based systems. Several studies have presented the many limitations to the current gold-standard that reduces the number of people who are able to benefit from a gait analysis. Those limitations in the current gold-standard include the requirements of large laboratory space, costly equipment, long instrumentation and collection time, and the potential for motion artifact from markers being placed on the skin. The purpose of this study …

The Effects And Analysis Of Implant Type And Surgical Approach In Total Hip Arthroplasty Dislocation Resistance, Brittany Marshall

Electronic Theses and Dissertations

Total hip arthroplasty (THA) is one of the most successful orthopaedic surgeries performed, in which the hip joint is reconstructed to decrease pain and to improve the functionality to the joint. Although these surgeries are very successful, there still remain areas for improvement, such as failures due to instability and dislocation of the implanted joint. The purpose of this thesis is to investigate the effect of surgical entrance approach on dislocation, the effect of implant type, and the effect of capsule repair and closure. The need to quantify the resistance to dislocation is important in understanding the effect that each …

A Longitudinal Examination Of Biomechanical Balance And Quantitative Multidomain Assessments During Recovery Following Sport-Related Concussion, Moira Kate Pyrhoda

Electronic Theses and Dissertations

Sport-related concussion is an inherent risk to athlete health in contact and collision sports. Both short- and long-term risks are associated with the injury. Short-term, athletes may develop post-concussion syndrome (PCS), the persistence of cognitive, physical, and emotional symptoms for weeks or months after injury. Athletes who return to play (RTP) prematurely are at increased risk for lower extremity injury and repeated concussion injuries. Long-term, history of multiple concussions have been linked to neurodegenerative diseases. Due to these risks, concussion assessments must be sensitive to the injury and useful in the diagnosis, recovery, and RTP phases of the injury.

Sideline …

Effects On Initial Fixation Of Cementless Tibial Trays In Total Knee Arthroplasty, Brooke Fritts Thompson

Electronic Theses and Dissertations

Bone mineral density (BMD), among other factors, largely effect the initial stability of the cementless tibial tray component in a total knee replacement (TKR), where increased motion at the tray-bone interface hinders bony ingrowth. With a lack of bony ingrowth, the cementless implant will not experience long-term success. Understanding which factors influence initial stability yields insight into surgical technique considerations and help inform a surgeon’s implant choice. The objective of this study was to evaluate factors influencing the initial stability of cementless tibial trays using a 6-degree of freedom (6-DOF) robotic joint simulator, the AMTI VIVO, and combined loading scenarios …

The Relative Contribution Of Fixation Features, Activity, And Tibiofemoral Conformity On Initial Stability Of Cementless Tibial Trays, James Sullivan Deacy

Electronic Theses and Dissertations

Initial stability of cementless total knee replacements (TKR) is critical to implant success as excessive motion between the bone and implant prevents bony ingrowth that is critical to the long-term survivability of cementless implants. Prior studies have shown that excessive micromotion causes fibrous tissue growth instead of beneficial bony growth. There are many factors that influence initial stability including the design of the tibial tray and the tibiofemoral articulations. Understanding the impacts of these design features on micromotion between the bone and implants is crucial to improving the performance of cementless TKR. Prior studies only tested for the effect of …

Laxity Of The Hip Capsule In Natural And Posteriorly Implanted Specimens, Luke Storer

Electronic Theses and Dissertations

The hip capsule consists of ligament tissue that surrounds the hip joint, providing stability to ensure proper alignment, prevent dislocation, and facilitate proper joint function. The objective of this study was to characterize the torque-rotation response of the natural and posteriorly implanted hip capsule in healthy cadaveric specimens in multiple degrees-of-freedom (DOF) and under combined loading scenarios using the AMTI VIVO, a robotic joint simulator. The anterior portion of the hip capsule was stained with Methylene Blue and virtual extensometers were calculated by Digital Image Correlation (DIC) software for Finite Element Analysis (FEA) model validation. The range of motion (ROM) …