Publications by authors named "John D Desjardins"

Bone healing after sliding hip screw internal fixation of intertrochanteric hip fractures is difficult to monitor with radiography. In this study, we describe and evaluate a device to non-invasively determine the loading on the screw implant as a possible qualitative indicator of bone healing. A novel load-sensing sliding hip screw (LS-SHS) was fabricated containing a radio-dense tungsten indicator rod that moves and can be measured within the screw cannulation when the screw bends under load via plain radiography.

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Uneven pressure distribution within a transtibial prosthetic socket can lead to discomfort, skin degradation, and suspended prosthesis use. Current custom interfaces to improve pressure distribution are often costly, time-intensive to fabricate, or cannot be incorporated into standard socket fabrication methods. In this technical note, we describe the design and preliminary clinical evaluation of a novel transtibial prosthetic socket insert with modifiable mechanical properties, which can be incorporated into the current clinical cycle of care.

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Introduction: Hippotherapy is a physical therapy tool that utilizes horseback riding to improve strength, coordination, gait, and balance. These benefits may be linked to similarities in kinematics and muscle activation between horseback riding and normal human gait, but this is not well represented in the literature, especially for muscle activation. The purpose of this study was to investigate the relationships between muscle activation of horseback riding and healthy human gait.

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Custom foot orthoses are used to treat a variety of foot pathologies. However, orthotic production requires significant hands-on fabrication time and expertise to produce orthoses that are both comfortable and effective. This paper introduces a novel 3D printed orthosis and fabrication method that utilizes custom architectures to produce variable-hardness regions.

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Background: In a reverse total shoulder arthroplasty, the altered glenohumeral joint center of rotation subjects the glenoid baseplate to increased shear forces and potential loosening.

Methods: This study examined glenoid baseplate micromotion and initial fixation strength with the application of direct shear force in a Sawbone model. The reverse total shoulder arthroplasty systems examined were the DJO Reverse® Shoulder Prosthesis, the Exactech Equinoxe® Reverse System, and the Tornier Aequalis Reverse Shoulder Prosthesis.

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The purpose of this study was to compare the effects of wearing older, lower-ranked football helmets (LRank) to wearing newer, higher-ranked football helmets (HRank) on pre- to post-season changes in cortical thickness in response to repetitive head impacts and assess whether changes in cortical thickness are associated with head impact exposure for either helmet type. 105 male high-school athletes (N = 52, N = 53) wore accelerometers affixed behind the left mastoid during all practices and games for one regular season of American football to monitor head impact exposure. Pre- and post-season magnetic resonance imaging (MRI) were completed to assess longitudinal changes in cortical thickness.

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This paper provides a synopsis of discussions related to the Learning Environments track of the Fourth BME Education Summit held at Case Western Reserve University in Cleveland, Ohio in May 2019. This summit was organized by the Council of Chairs of Bioengineering and Biomedical Engineering, and participants included over 300 faculty members from 100+ accredited undergraduate programs. The Learning Environments track had six interactive workshops that provided facilitated discussion and provide recommendations in the areas of: (1) Authentic project/problem identification in clinical, industrial, and global settings, (2) Experiential problem/project-based learning within courses, (3) Experiential learning in co-curricular learning settings, (4) Team-based learning, (5) Teaching to reach a diverse classroom, and (6) innovative platforms and pedagogy.

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The biomechanical relationship between horse and rider in equine-assisted activities and therapies has been largely unexplored. The three-dimensional stimulation of the horse's gait has potential to improve rider musculature and coordination, especially in an older adult population. This study utilized dual-axis goniometers and video motion capture tracking to simultaneously track horse and rider hip flexion and extension.

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Objectives: To overcome the shortage of personal protective equipment and airborne infection isolation rooms (AIIRs) in the COVID-19 pandemic, a collaborative team of research engineers and clinical physicians worked to build a novel negative pressure environment in the hopes of improving healthcare worker and patient safety. The team then sought to test the device's efficacy in generating and maintaining negative pressure. The goal proved prescient as the US Food and Drug Administration (FDA) later recommended that all barrier devices use negative pressure.

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The emergence of the SARS-CoV-2 pandemic has imposed a multitude of complications on healthcare facilities. Healthcare professionals had to develop creative solutions to deal with resource shortages and isolation spaces when caring for COVID positive patients. Among many other solutions, facilities have utilized engineering strategies to mitigate the spread of viral contamination within the hospital environment.

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This biomechanical study evaluates the performance of a solid titanium-alloy intra-medullary () clavicular screw in torsion and cantilever bending in cadaveric clavicle specimens with simulated simple oblique and butterfly wedge midshaft fractures. Thirty-two fresh-frozen male clavicles were sorted into six experimental groups: Torsion Control, Torsion Simple Oblique Fracture, Torsion Butterfly Wedge Fracture, Bending Control, Bending Simple Oblique Fracture, and Bending Butterfly Wedge Fracture. The experimental groups were controlled for density, length, diameter, and laterality.

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We describe a method to measure micron to millimeter displacement through tissue using an upconversion spectral ruler. Measuring stiffness (displacement under load) in muscles, bones, ligaments, and tendons is important for studying and monitoring healing of injuries. Optical displacement measurements are useful because they are sensitive and noninvasive.

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While using a prosthesis, transtibial amputees can experience pain and discomfort brought on by large pressure gradients at the interface between the residual limb and the prosthetic socket. Current prosthetic interface solutions attempt to alleviate these pressure gradients using soft homogenous liners to reduce and distribute pressures. This research investigates an additively manufactured metamaterial inlay with a tailored mechanical response to reduce peak pressure gradients around the limb.

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Introduction: Compression is integral to the management of edema and the prevention of venous leg ulcers (VLUs).

Objective: The aim of this study is to assess the sub-bandage pressure distribution under 3 compression applications as well as to assess the impact of an innovative primary wound dressing, applied under the compression products, on pressure distribution.

Materials And Methods: A series of controlled tests were performed using a simulated leg model (SLM).

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Background: While vibration therapy has shown encouraging results across many fields of medicine in the last decade, its role as originally envisioned for bone health remains uncertain. Especially regarding its efficacy in promoting fracture healing, mixed and incomplete outcomes suggest a need to clarify its potential. In particular, the definitive effect of vibration, when isolated from the confounding mechanical inputs of gait and stabilizing instrumentation, remains largely unknown.

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A luminescent spectral ruler was developed to measure micrometer to millimeter displacements through tissue. The spectral ruler has two components: a luminescent encoder patterned with alternating stripes of two spectrally distinct luminescent materials and an analyzer mask with periodic transparent windows the same width as the encoder stripes. The analyzer mask is placed over the encoder and held so that only one type of luminescent stripe is visible through the window; sliding the analyzer over the encoder modulates the luminescence spectrum acquired through the analyzer windows, enabling detection of small displacements without imaging.

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The field of engineering is increasingly appreciating the value of diversity for innovative design solutions. Successful engineering depends on our ability to explore constrained parameter spaces for finding the best solutions, and more diverse minds and experiences enable us to explore the entire potential solution space more thoroughly, more quickly, and more creatively. With a goal to expand the diversity of experiences and mindsets in our undergraduate bioengineering curricula, Arusha Technical College (ATC) in Arusha, Tanzania and Clemson University (CU) in Clemson, South Carolina, U.

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Although horseback riding is a well-established means of rehabilitation therapy for a variety of human patients, there are few data on the biomechanical relationships between horse and rider during such hippotherapy. We simultaneously tracked the movements of a horse with several different novice riders, under conditions similar to hippotherapy, to evaluate whether horses pass the same motion to different riders while being lead at a walk. Riders were outfitted with a goniometric data collection system that recorded the angles of flexion and extension and lateral bending of the thoracic and lumbar spine, as well as the flexion, extension, abduction, and adduction of each hip.

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Knee arthrodesis is commonly performed to treat joint pain and instability in cases of multiple failed knee replacement surgeries, bone loss, traumatic injury, infection, or loss of the quadriceps extensor mechanism, but its mechanics are poorly understood. This study quantified the changes in gait kinematics and kinetics induced by simulating knee arthrodesis. A total of 10 healthy subjects (M/F, n = 5/5; aged 18-23) with no history of gait abnormalities were recruited for this study, and knee arthrodesis was simulated for 0 through 24 h using an immobilizing knee brace.

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A biomedical sensor was developed to measure local pH near orthopedic implants to detect and study implant-associated infection. The sensor is read using plain radiography, a technique which is noninvasive, inexpensive, ubiquitously available in medical facilities, and routinely used in diagnosis and follow-up. The sensor comprises a radiopaque tungsten indicator pin embedded within a chemically responsive hydrogel that exhibits a pH-dependent swelling.

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Current total knee replacement designs work to address clinically desired knee stability and range of motion through a balance of retained anatomy and added implant geometry. However, simplified implant geometries such as bearing surfaces, posts, and cams are often used to replace complex ligamentous constraints that are sacrificed during most total knee replacement procedures. This article evaluates a novel total knee replacement design that incorporates synthetic ligaments to enhance the stability of the total knee replacement system.

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In total knee replacement surgery, implant alignment is one of the most important criteria for successful long-term clinical outcome. During total knee replacement implantation, femoral and tibial alignment are determined through appropriate bone resections, which could vary based on patient anatomy, implant design and surgical technique and further influence loading conditions and clinical outcomes. The current research focused on three critical alignment parameters for total knee replacement insertion: femoral component internal/external (I/E) rotation, varus-valgus tibiofemoral angulation and posterior tibial slope.

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Current orthopaedic clinical methods do not provide an objective measure of fracture healing or weight bearing for lower extremity fractures. The following report describes a novel approach involving in-situ strain sensors to objectively measure fracture healing. The sensor uses a cantilevered indicator pin that responds to plate bending and an internal scale to demonstrate changes in the pin position on plain film radiographs.

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Background: Glenoid component loosening is common in total shoulder arthroplasty (TSA), often resulting from the mechanical interaction of glenohumeral components. This cadaveric study was performed to evaluate and to compare commercially available onlay and inlay glenoid prosthetic designs with respect to loading characteristics and loosening.

Methods: Sixteen prescreened cadaveric shoulders (8 matched pairs) underwent either onlay or inlay TSA.

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Background: The incidence and prevalence of knee arthrodesis (fusion) in the United States is largely unknown, in spite of numerous case reports and review articles that have called attention to this life altering procedure.

Purpose: This study was conducted to determine long-term knee arthrodesis incidence and patient populations, and to characterize the associated healthcare burden.

Methods: The Nationwide Inpatient Sample was used to evaluate knee arthrodesis procedures performed in the United States between 1993 and 2011.

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