Biomechanics

Biomechanics is a vast discipline within the field of Biomedical Engineering. It explores the underlying mechanics of how biological and physiological systems move. It encompasses important clinical applications to address questions related to medicine using engineering mechanics principles. Biomechanics includes interdisciplinary concepts from engineers, physicians, therapists, biologists, physicists, and mathematicians. Through their collaborative efforts, biomechanics research is ever changing and expanding, explaining new mechanisms and principles for dynamic human systems. Biomechanics is used to describe how the human body moves, walks, and breathes, in addition to how it responds to injury and rehabilitation. Advanced biomechanical modeling methods, such as inverse dynamics, finite element analysis, and musculoskeletal modeling are used to simulate and investigate human situations in regard to movement and injury. Biomechanical technologies are progressing to answer contemporary medical questions. The future of biomechanics is dependent on interdisciplinary research efforts and the education of tomorrow’s scientists

Computer Aided Tools for the Design and Planning of Personalized Shoulder Arthroplasty

La artroplastia de hombro es el tercer procedimiento de reemplazo articular más común, después de la artroplastia de rodilla y cadera, y actualmentees el de más rápido crecimiento en el campo ortopédico. Las principales opciones quirúrgicas incluyen la artroplastia total de hombro (TSA), en la quese restaura la anatomía articular normal, y, para pacientes con un manguito rotador completamente desgarrado, la artroplastia inversa de hombro (RSA), en la que la bola y la cavidad de la articulación glenohumeral se cambian. A pesar del progreso reciente y los avances en el diseño, las tasas de complicaciones reportadas para RSA son más altas que las de la artroplastia de hombro convencional. Un enfoque específico para el paciente, en el que los médicos adaptan el tratamiento quirúrgico a las características del mismo y al estado preoperatorio, por ejemplo mediante implantes personalizados y planificación previa, puede ayudar a reducir los problemas postoperatorios y mejorar el resultado funcional. El objetivo principal de esta tesis es desarrollar y evaluar métodos novedosos para RSA personalizado, utilizando tecnologías asistidas por ordenador de última generación para estandarizar y automatizar las fases de diseño y planificación.Los implantes personalizados son una solución adecuada para el tratamiento de pacientes con pérdida extensa de hueso glenoideo. Sin embargo, los ingenieros clínicos se enfrentan a muchas variables en el diseño de implantes (número y tipo de tornillos, superficie de contacto, etc.) y una gran variabilidad anatómica y patológica. Actualmente, no existen herramientas objetivas para guiarlos a la hora de elegir el diseño óptimo, es decir, con suficiente estabilidad inicial del implante, lo que hace que el proceso de diseño sea tedioso, lento y dependiente del usuario. En esta tesis, se desarrolló una simulación de Virtual Bench Test (VBT) utilizando un modelo de elementos finitos para evaluar automáticamente la estabilidad inicial de los implantes de hombro personalizados. A través de un experimento de validación, se demostró que los ingenieros clínicos pueden utilizar el resultado de Virtual Bench Test como referencia para respaldar sus decisiones y adaptaciones durante el proceso de diseño del implante.Al diseñar implantes de hombro, el conocimiento de la morfología y la calidad ósea de la escápula en toda la población es fundamental. En particular, se tienen en cuenta las regiones con la mejor reserva ósea (hueso cortical) para definir la posición y orientación de los orificios de los tornillos, mientras se busca una fijación óptima. Como alternativa a las mediciones manuales, cuya generalización está limitada por el análisis de pequeños subconjuntos de pacientes potenciales, Statistical Shape Models (SSMs) se han utilizado comúnmente para describir la variabilidad de la forma dentro de una población. Sin embargo, estos SSMs normalmente no contienen información sobre el grosor cortical.Por lo tanto, se desarrolló una metodología para combinar la forma del hueso escapular y la morfología de la cortical en un SSM. Primero, se presentó y evaluó un método para estimar el espesor cortical, a partir de un análisis de perfil de Hounsfield Unit (HU). Luego, utilizando 32 escápulas sanas segmentadas manualmente, se creó y evaluó un modelo de forma estadística que incluía información de la cortical. La herramienta desarrollada se puede utilizar para implantar virtualmente un nuevo diseño y probar su congruencia dentro de una población virtual generada, reduciendo así el número de iteraciones de diseño y experimentos con cadáveres.Las mediciones del alargamiento de los músculos deltoides y del manguito rotador durante la planificación quirúrgica pueden ayudar a los médicos aseleccionar un diseño y una posición de implante adecuados. Sin embargo, tal evaluación requiere la indicación de puntos anatómicos como referencia para los puntos de unión de los músculos, un proceso que requiere mucho tiempo y depende del usuario, ya que a menudo se realiza manualmente. Además, las imágenes médicas, que se utilizan normalmente para la artroplastia de hombro,contienen en su mayoría solo el húmero proximal, lo que hace imposible indicarlos puntos de unión de los músculos que se encuentran fuera del campo de visión de la exploración. Por lo tanto, se desarrolló y evaluó un método totalmente automatizado, basado en SSM, para medir la elongación del deltoides y del manguito rotador. Su aplicabilidad clínica se demostró mediante la evaluación del rendimiento de la estimación automatizada de la elongación muscular para un conjunto de articulaciones artríticas del hombro utilizadas para la planificación preoperatoria de RSA, lo que confirma que es una herramienta adecuada para los cirujanos a la hora de evaluar y refinar las decisiones clínicas.En esta investigación, se dio un paso importante en la dirección de un enfoque más personalizado de la artroplastia inversa de hombro, en el que el manejo quirúrgico, es decir, el diseño y la posición del implante, se adapta a las características específicas del paciente y al estado preoperatorio. Al aplicar tecnologías asistidas por computadora en la práctica clínica, el proceso de diseño y planificación se puede automatizar y estandarizar, reduciendo así los costos y los plazos de entrega. Además, gracias a los métodos novedosos presentados en esta tesis, esperamos en el futuro una adopción más amplia del enfoque personalizado, con importantes beneficios tanto para los cirujanos como para los pacientes.Shoulder arthroplasty is the third most common joint replacement procedure, after knee and hip arthroplasty, and currently the most rapidly growing one in the orthopaedic field. The main surgical options include total shoulder arthroplasty (TSA), in which the normal joint anatomy is restored, and, for patients with a completely torn rotator cuff, reverse shoulder arthroplasty (RSA), in which the ball and the socket of the glenohumeral joint are switched. Despite the recent progress and advancement in design, the reported rates of complication for RSA are higher than those of conventional shoulder arthroplasty. A patient-specific approach, in which clinicians adapt the surgical management to patient characteristics and preoperative condition, e.g. through custom implants and pre-planning, can help to reduce postoperative problems and improve the functional outcome. The main goal of this thesis is to develop and evaluate novel methods for personalized RSA, using state-of-the-art computer aided technologies to standardize and automate the design and planning phases. Custom implants are a suitable solution when treating patients with extensive glenoid bone loss. However, clinical engineers are confronted with an enormous implant design space (number and type of screws, contact surface, etc.) and large anatomical and pathological variability. Currently, no objective tools exist to guide them when choosing the optimal design, i.e. with sufficient initial implant stability, thus making the design process tedious, time-consuming, and user-dependent. In this thesis, a Virtual Bench Test (VBT) simulation was developed using a finite element model to automatically evaluate the initial stability of custom shoulder implants. Through a validation experiment, it was shown that the virtual test bench output can be used by clinical engineers as a reference to support their decisions and adaptations during the implant design process. When designing shoulder implants, knowledge about bone morphology and bone quality of the scapula throughout a certain population is fundamental. In particular, regions with the best bone stock (cortical bone) are taken into account to define the position and orientation of the screw holes, while aiming for an optimal fixation. As an alternative to manual measurements, whose generalization is limited by the analysis of small sub-sets of the potential patients, Statistical Shape Models (SSMs) have been commonly used to describe shape variability within a population. However, these SSMs typically do not contain information about cortical thickness. Therefore, a methodology to combine scapular bone shape and cortex morphology in an SSM was developed. First, a method to estimate cortical thickness, starting from a profile analysis of Hounsfield Unit (HU), was presented and evaluated. Then, using 32 manually segmented healthy scapulae, a statistical shape model including cortical information was created and assessed. The developed tool can be used to virtually implant a new design and test its congruency inside a generated virtual population, thus reducing the number of design iterations and cadaver labs. Measurements of deltoid and rotator cuff muscle elongation during surgical planning can help clinicians to select a suitable implant design and position. However, such an assessment requires the indication of anatomical landmarks as a reference for the muscle attachment points, a process that is time-consuming and user-dependent, since often performed manually. Additionally, the medical images, which are normally used for shoulder arthroplasty, mostly contain only the proximal humerus, making it impossible to indicate those muscle attachment points which lie outside of the field of view of the scan. Therefore, a fully-automated method, based on SSM, for measuring deltoid and rotator cuff elongation was developed and evaluated. Its clinical applicability was demonstrated by assessing the performance of the automated muscle elongation estimation for a set of arthritic shoulder joints used for preoperative planning of RSA, thus confirming it a suitable tool for surgeons when evaluating and refining clinical decisions. In this research, a major step was taken into the direction of a more personalized approach to Reverse Shoulder Arthroplasty, in which the surgical management, i.e. implant design and position, is adapted to the patient-specific characteristics and preoperative condition. By applying computer aided technologies in the clinical practice, design and planning process can be automated and standardized, thus reducing costs and lead times. Additionally, thanks to the novel methods presented in this thesis, we expect in the future a wider adoption of the personalized approach, with important benefits both for surgeons and patients.<br /

The Evidence of Aquatic Therapy for Painful Shoulder Disability.

O objetivo geral deste trabalho foi estudar a terapia aquática para a incapacidadedolorosa do ombro com fraca evidência científica. Os achados estão focados nalesão pós-operatória dos rotadores da coifa, disfunção do membro superior ecaracterização biomecânica do ombro. O que acontece nas lesões silenciosasdo ombro? As pessoas idosas adaptam-se à sua disfunção e procuram umamaneira mais fácil de se movimentar. Para promover o envelhecimentosaudável, os médicos recomendam atividades aquáticas devido ao baixoimpacto no sistema musculosquelético. Utiliza-se a água profunda emprogramas de longa duração de terapia aquática ou atividades aquáticas.Estudou-se a influência da flutuabilidade na abdução do ombro e na extensãohorizontal em águas profundas, através da análise biomecânica do movimentodos membros superiores em duplo meio, encontrou-se influência significativados dispositivos na amplitude de movimento, mas não na velocidade ousuavidade. Em adultos mais velhos com condições crónicas de saúde edisfunção dolorosa do membro superior, estudou-se as expectativas, satisfação,perceção funcional e a associação entre a Escala de Perceção Funcional (FPS)e o Questionário de Incapacidade de Braço, Ombro e Mão (DASH). Tambéminvestigámos, os efeitos imediatos dos pacientes, numa sessão de terapiaaquática, bem como o efeito do destreino da terapia aquática após uma pausade verão. Os resultados mostraram evidências de programas contínuos, pois odestreino é significativo para o equilíbrio e a dor. Os objetivos de um programade treino em adultos mais velhos sugerem ser rapidamente alcançados com umprograma anual. Num estudo de caso de uma paciente de 60 anos estudou-seatravés de cinemática e EMG os cinco testes dos rotadores da coifa com valor 9na escala VAS_Pain e 57,80 para a incapacidade da escala de braço, ombro emão (DASH). O resultado na ROM e ordem de recrutamento de ativação dosquatro músculos esquerdo e direito, em todos os testes, sugeriu que o sintomade dor ocorra à direita, confirmando o teste positivo. Espera-se contribuir parauma melhor compreensão e planeamento do tratamento de lesões dolorosas noombro de adultos seniores em programas de terapia aquática em grupo.Palavras-chave: TERAPIA AQUÁTICA, OMBRO DOLOROSO, EFEITOSIMEDIATOS, BIOMECÂNICA, AVALIAÇÃO GLOBAL.The overall goal of this work was to study Aquatic Therapy for Painful ShoulderDisability. Scientific evidence is not strong. The findings are focused on thepostoperative rotator cuff lesion, upper limb dysfunction and biomechanicalcharacterization of the shoulder. What happens in silent shoulder injuries? Agingpeople adapt to their disability and look for an easier way to move. To promotehealthy aging, doctors recommend aquatic activities because of the low impacton the skeletal muscle system. The deep-water is one of the techniques used inlong-term programs of aquatic therapy or aquatic activities, with excellentadherence among the elderly. We studied the buoyancy influence in shoulderabduction and horizontal extension in deep-water, through the dual-mediabiomechanical analysis of the movement of upper limbs, we found a significantinfluence of the devices on the range of motion, but not on speed or smoothness,these findings showed evidence for making a decision. In a sample of older adultswith chronical health conditions and painful dysfunction of the upper limb, westudied for their expectations, satisfaction, functional perception and theassociation between a functional scale based on the International Classificationof Functioning, Disability and Health (ICF) and Disability of Arm, Shoulder andHand (DASH). Deeper, what immediate effects do patients had from an aquatictherapy session? In addition, what was the effect of detraining of aquatic therapyafter a summer pause? The findings showed evidence for continuous programs,as detraining is significant for balance and pain. The goals of a training programsuggest being quickly achieved on older adults with a complete program. A casereport on one female patient, 60 years old, studied kinematic and EGM duringthe five rotator cuff tests of a patient with grade 9 on the VAS_Pain scale and57.80 for the disability of arm, shoulder and hand scale (DASH). The findings byROM and the recruitment order of activation of the four muscles, left and rightsides, in all tests. This suggests that pain symptom occurs in the right confirmingthe positive test. Through our studies, we hope to contribute to a betterunderstanding and planning of treatment painful shoulder injuries older adultparticipating in a group aquatic therapy program

Diagnostic Musculoskeletal Imaging: How Physical Therapists Utilize Imaging in Clinical Decision-Making

This qualitative study describes how physical therapist experts in musculoskeletal disorders evaluate and interpret imaging studies and how they employ imaging in clinical decision-making. The informants are physical therapists who are certified orthopedic clinical specialists (OCS) and/or fellows of the American Academy of Orthopaedic Manual Physical Therapists (AAOMPT). The study employed web conferencing to display patient cases, record screen-capture videos, and to conduct interviews. Informants were observed and their activity video-captured as they evaluated imaging studies and, afterwards, interviews were employed to explore the processes they utilized to evaluate and interpret the images and to discuss imaging-related clinical decision-making, including possible functional consequences of changes seen in the images, contraindications to treatment, and indications for referral. The interviews were transcribed and analyzed in the tradition of grounded theory. This study found that the informants’ evaluation of imaging studies was contextual and non-systematic, guided by the clinical presentation. The informants used imaging studies to provide a deeper understanding of clinical findings and widen perspectives, arriving at clinical decisions through the synthesis of imaging, clinical findings, and didactic knowledge. They tended to look for imaging evidence of interference with normal motion, rather than evidence of pathology. Overall, the informants expressed conservative views on the use of imaging, noting they would rather use clinical findings and treatment response than imaging findings as a basis for referral to other health care professionals. Using imaging studies to support clinical decision-making can provide physical therapists a wider perspective when planning treatment interventions. By showing physical therapists’ approach to interpreting imaging studies and how this relates to their clinical decision-making, the findings of this study could contribute to discussions of the place of imaging in physical therapist practice, as well as help set objectives for imaging curricula in professional-level and continuing education

Characterization of a Contact-Stylus Surface Digitization Method Using Collaborative Robots: Accuracy Evaluation in the Context of Shoulder Replacement or Resurfacing

Total shoulder arthroplasty (TSA) is the third most common joint replacement. While robot-assisted hip and knee replacement technologies have enjoyed extensive development, this has been limited in the upper limb. This work focused on quantifying the localization accuracy of a robotic system, and evaluating its efficacy in the context of TSA. A collaborative robot was fitted with a stylus tip to perform manual surface digitizations using the robot’s encoder output. In the first experiment, two precision-machined master cubes, representing the working volume around a glenoid structure, were used for system validation. Next, cadaveric glenoids were digitized and compared to a ‘gold standard’ laser scanner. Digitization errors were 0.37±0.27 mm, showing that collaborative robotics can be used for osseous anatomy digitization. This thesis presents two novel concepts: 1) use of collaborative robotics for manually operated surface digitizing, and 2) optical fiducial technique, allowing registration between a laser scanner and stylus digitizer

Prevention of upper limb symptoms and signs of nerve afflictions in computer operators: The effect of intervention by stretching

<p>Abstract</p> <p>Background</p> <p>In a previous study of computer operators we have demonstrated the relation of upper limb pain to individual and patterns of neurological findings (reduced function of muscles, sensory deviations from normal and mechanical allodynia of nerve trunks). The identified patterns were in accordance with neural afflictions at three specific locations (brachial plexus at chord level, posterior interosseous and median nerve on elbow level). We have introduced an intervention program aiming to mobilize nerves at these locations and tested its efficacy.</p> <p>Methods</p> <p>125 and 59, respectively, computer operators in two divisions of an engineering consultancy company were invited to answer a questionnaire on upper limb symptoms and to undergo a blinded neurological examination. Participants in one division were subsequently instructed to participate in an upper limb stretching course at least three times during workdays in a six month period. Subjects from the other division served as controls. At the end of the intervention both groups were invited to a second identical evaluation by questionnaire and physical examination. Symptoms and findings were studied in the right upper limb. Perceived changes of pain were recorded and individual and patterns of physical findings assessed for both groups at baseline and at follow-up. In subjects with no or minimal preceding pain we additionally studied the relation of incident pain to the summarized findings for parameters contained in the definition of nerve affliction at the three locations.</p> <p>Results</p> <p>Summarized pain was significantly reduced in the intervention group but unchanged in controls. After the intervention, fewer neurological abnormalities in accordance with nerve affliction were recorded for the whole material but no conclusion could be drawn regarding the relation to the intervention of this reduction. Incident pain correlated to findings in accordance with the three locations of nerve affliction.</p> <p>Conclusion</p> <p>A six month course of stretching seems to reduce upper limb symptoms in computer operators but we could not demonstrate an influence on neurological physical findings in this sample. The relation of incident symptoms to identified neurological patterns provides additional support to the construct validity of the employed neurological examination.</p

Aerospace Medicine and Biology. A continuing bibliography with indexes, supplement 151

This bibliography lists 195 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1976

Computer-aided surface estimation of pain drawings – intra- and inter-rater reliability

Pain drawings are often utilized in the documentation of pain conditions. The aim here was to investigate intra- and inter-rater reliability of area measurements performed on pain drawings consecutively, using the computer program Quantify One. Forty-eight patients with chronic nonmalignant pain had shaded in their experienced pain on the front and back views of a pain drawing. The templates were scanned and displayed on a 17-inch computer screen. Two independent examiners systematically encircled the shaded-in areas of the pain drawings with help of a computer mouse, twice each on two separate days, respectively. With this method it is possible to encircle each marked area and to obtain immediate details of its size. The total surface area (mm2) was calculated for each pain drawing measurement. Each examiner measured about 2400 areas, and as a whole, the number of areas measured varied only by 3%. The intra-rater reliability was high with intraclass correlation coefficients 0.992 in Examiner A and 0.998 in Examiner B. The intra-individual absolute differences were small within patients within one examiner as well as between the two examiners. The inter-rater reliability was also high. Still, significant differences in the absolute mean areas (13%) were seen between the two examiners in the second to fourth measurement sessions, indicating that one of the examiners measured systematically less. The measurement error was ≤10%, indicating that use of the program would be advantageous both in clinical practice and in research, but if repeated, preferably with the same examiner. Since pain drawings with this method are digitized, high quality data without loss of information is possible to store in electronic medical records for later analysis, both regarding precise location and size of pain area. We conclude that the computer program Quantify One is a reliable method to calculate the areas of pain drawings

Machine learning in orthopedics: a literature review

In this paper we present the findings of a systematic literature review covering the articles published in the last two decades in which the authors described the application of a machine learning technique and method to an orthopedic problem or purpose. By searching both in the Scopus and Medline databases, we retrieved, screened and analyzed the content of 70 journal articles, and coded these resources following an iterative method within a Grounded Theory approach. We report the survey findings by outlining the articles\u2019 content in terms of the main machine learning techniques mentioned therein, the orthopedic application domains, the source data and the quality of their predictive performance