Recent trends, technical concepts and components of computer-assisted orthopedic surgery systems: A comprehensive review

Computer-assisted orthopedic surgery (CAOS) systems have become one of the most important and challenging types of system in clinical orthopedics, as they enable precise treatment of musculoskeletal diseases, employing modern clinical navigation systems and surgical tools. This paper brings a comprehensive review of recent trends and possibilities of CAOS systems. There are three types of the surgical planning systems, including: systems based on the volumetric images (computer tomography (CT), magnetic resonance imaging (MRI) or ultrasound images), further systems utilize either 2D or 3D fluoroscopic images, and the last one utilizes the kinetic information about the joints and morphological information about the target bones. This complex review is focused on three fundamental aspects of CAOS systems: their essential components, types of CAOS systems, and mechanical tools used in CAOS systems. In this review, we also outline the possibilities for using ultrasound computer-assisted orthopedic surgery (UCAOS) systems as an alternative to conventionally used CAOS systems.Web of Science1923art. no. 519

Role of 3D printed customized implants in periarticular fractures: a narrative review

“3D printing” is a common term used for a number of technologies which operate on the principle of converting a computer-generated 3D image into a physical model. Advantage of 3D printed parts is that they can assume complex shape, with solid and porous components that can be combined to provide the best combination of strength and performances and can help visualize the complex fractures which are difficult to apprehend with conventional imaging. Presently, the primary applications for 3D printing are the production of anatomical models for planning and surgery simulation, patient-specific instruments and custom-made prosthesis which have transformed how orthopedic problems are addressed now. This review aims to describe the utility and future directives into the application of this technology in orthopedics

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 /

Computational Techniques to Predict Orthopaedic Implant Alignment and Fit in Bone

Among the broad palette of surgical techniques employed in the current orthopaedic practice, joint replacement represents one of the most difficult and costliest surgical procedures. While numerous recent advances suggest that computer assistance can dramatically improve the precision and long term outcomes of joint arthroplasty even in the hands of experienced surgeons, many of the joint replacement protocols continue to rely almost exclusively on an empirical basis that often entail a succession of trial and error maneuvers that can only be performed intraoperatively. Although the surgeon is generally unable to accurately and reliably predict a priori what the final malalignment will be or even what implant size should be used for a certain patient, the overarching goal of all arthroplastic procedures is to ensure that an appropriate match exists between the native and prosthetic axes of the articulation. To address this relative lack of knowledge, the main objective of this thesis was to develop a comprehensive library of numerical techniques capable to: 1) accurately reconstruct the outer and inner geometry of the bone to be implanted; 2) determine the location of the native articular axis to be replicated by the implant; 3) assess the insertability of a certain implant within the endosteal canal of the bone to be implanted; 4) propose customized implant geometries capable to ensure minimal malalignments between native and prosthetic axes. The accuracy of the developed algorithms was validated through comparisons performed against conventional methods involving either contact-acquired data or navigated implantation approaches, while various customized implant designs proposed were tested with an original numerical implantation method. It is anticipated that the proposed computer-based approaches will eliminate or at least diminish the need for undesirable trial and error implantation procedures in a sense that present error-prone intraoperative implant insertion decisions will be at least augmented if not even replaced by optimal computer-based solutions to offer reliable virtual “previews” of the future surgical procedure. While the entire thesis is focused on the elbow as the most challenging joint replacement surgery, many of the developed approaches are equally applicable to other upper or lower limb articulations

3D planning and patient specific instrumentation for intraarticular corrective osteotomy of trapeziometacarpal-, metacarpal and finger joints

BACKGROUND Intra-articular malunions of the finger can lead to deformity and loss of function and can be treated with intra-articular corrective osteotomies. The aim of this study was to evaluate radiographic joint congruency, feasibility and functional outcome of three-dimensional (3D) printed patient-specific instrumentation (PSI) for corrective osteotomies at the trapeziometacarpal and finger joints. METHODS Computer-tomography (CT) scans were acquired preoperatively for standard 3D planning, which was followed by calculation of cutting planes and the design of individualized bone surface contact drilling, sawing and reposition guides. Follow-up CT scans and clinical examinations (range of motion, grip strength) were performed. Postoperative complications were documented and patient-reported outcome measurements were assessed (Single Assessment Numeric Evaluation (SANE) score, brief Michigan Hand Questionnaire (MHQ)). RESULTS Ten patients (mean age 28.4 ± 12.8,range 13.8-51.3) years) were included with a mean follow-up of 21 ± 18 (3-59) months including seven osteotomies at the trapeziometacarpal or metacarpophalangeal joints and three at the proximal interphalangeal joint (PIP). All radiographic follow-up examinations showed the planned correction with good joint congruency and regular osseous consolidation. At the latest follow-up, the range of motion (ROM) increased and the average grip strength recovered to the level of the contralateral side. No postoperative complication was detected. The mean SANE score improved from 44 ± 23 (0-70) to 82 ± 12 (60-90) after a mean of 72 ± 20 (44-114) months. The mean postoperative brief MHQ was 92 ± 8 (71-98). CONCLUSION The use of 3D PSI in treating intra-articular malunions at the trapeziometacarpal and finger joints restored articular congruency accurately. ROM and grip strength improved postoperatively comparable to the healthy contralateral side and patient-reported outcome measures improved after medium-term follow-up

Development and application features of 3-d atlas of transosseous elements positions for pre-surgery planning of the shin bones osteosynthesis

КОНЕЧНОСТИ НИЖНЕЙ ТРАВМЫЛОДЫЖКИ ПОВРЕЖДЕНИЯГОЛЕНОСТОПНОГО СУСТАВА ПОВРЕЖДЕНИЯПЕРЕЛОМЫ КОСТЕЙ ГОЛЕНИПЕРЕЛОМА ИММОБИЛИЗАЦИЯ ВНУТРЕННЯЯОСТЕОСИНТЕЗ ПЕРЕЛОМАЧРЕСКОСТНЫЙ ОСТЕОСИНТЕЗПРЕДОПЕРАЦИОННОЕ ВЕДЕНИЕ БОЛЬНОГОПРЕДОПЕРАЦИОННЫЙ ПЕРИОД, ВЕДЕНИЕПРЕДОПЕРАЦИОННЫЙ ЭТАП ЛЕЧЕНИЯПРЕДОПЕРАЦИОННОЕ ПЛАНИРОВАНИЕКОМПЬЮТЕРНОЕ МОДЕЛИРОВАНИЕТРЕХМЕРНАЯ МОДЕЛЬЦель. Оптимизировать процесс предоперационного планирования чрескостного остеосинтеза при переломах костей голени путем разработки и применения 3-D атласа позиций чрескостных элементов. Материал и методы. На основе поперечных компьютерных томографических сканов интактной нижней конечности взрослого человека, с помощью программного пакета 3-D Doctor в автоматическом режиме, созданы трехмерные имитационные модели костей голени и окружающих их мягкотканных структур. Данные модели экспортированы в программный комплекс Autodesk Inventor 11. В режиме Part Modeling проведено разделение модели мягкотканных структур голени на 96 частей – сегментов, соответствующих позициям для проведения чрескостных элементов согласно методу унифицированного обозначения чрескостного остеосинтеза, и их сохранение в отдельных файлах. В режиме "Assembly" программы проведена сборка сегментов голени. Результаты. Предложен алгоритм действий для создания 3-D атласа позиций для проведения чрескостных элементов, согласно которому в программе Autodesk Inventor 11 созданы трехмерные имитационные модели систем "голень – аппарат внешней фиксации" и проведен анализ их возможностей по предоперационному планированию чрескостного остеосинтеза. В результате проведенного исследования установлено, что использование 3-D атласа позиций обеспечивает возможность выбора оптимальной конструкции и наиболее рациональной, в каждой конкретной клинической ситуации, компоновки аппарата внешней фиксации; определения количества и оптимальных уровней расположения опор; выбора типа и наиболее целесообразных мест проведения чрескостных элементов. Заключение. Применение 3-D атласа позиций чрескостных элементов позволяет вплотную приблизиться к решению вопроса предоперационного планирования с позиций комплексного подхода: адекватного существующей клинической ситуации выбора типа аппарата внешней фиксации, его компоновки, определения количества чрескостных элементов, направлений и плоскостей их проведения, что позволит значительно уменьшить количество технических ошибок, обеспечит снижение рисков возникновения осложнений и будет способствовать достижению положительных анатомо-функциональных результатов в подавляющем большинстве клинических случаев.Objective. To improve the pre-surgery planning of transosseous osteosynthesis in the shin bone fractures by developing and applying the 3-D atlas of transosseous elements positions. Methods. On the basis of transverse computer tomographic scans of the intact lower limb of an adult using the 3-D Doctor software package, three-dimensional simulation models of the shin bones and surrounding soft tissue structures were created in the automatic mode. These models were exported as separate files into the Autodesk Inventor 11 software package. In Part Modeling mode, the division of the model of the soft tissue structures of the shin into 96 parts was carried out - the segments corresponding to the positions for passing the transosseous elements according to the method of the unified marking of transosseous osteosynthesis and their preservation in separate files. In Assembly mode, the assemblage of the shin segments has been performed. Results. The algorithm for the creation of 3-D atlas of transosseous elements positions was proposed, according to which the three-dimensional simulation models of the "shin - external fixation device" system were created in the Autodesk Inventor 11 program and the analysis of their possibilities regarding pre-surgery planning of transosseous osteosynthesis was conducted. As a result of the research, it was found out that the use of the 3-D atlas of positions provides an opportunity for selecting the optimal design and the most efficient layout of the external fixation device in each particular clinical situation; determination of the number and optimal layout levels of the supports; the choice of the type and the most appropriate places for passing of the transosseous elements. Conclusions. The application of 3-D Atlas of transosseous elements positions permits to approach the solution of the problem of pre-surgery planning from the standpoint of an integrated approach to choosing the type of external fixation device that is adequate to the existing clinical situation, its layout, determining the number of transosseous elements, directions and planes for passing them, which will allow reducing significantly the number of technical errors, reducing the risk of complications and promoting the achievement of positive anatomical and functional results in the vast majority of clinical cases

A Novel Method for the Approximation of Humeral Head Retrotorsion Based on Three-Dimensional Registration of the Bicipital Groove

BACKGROUND The accurate restoration of premorbid anatomy is key for the success of reconstructive surgeries of the proximal part of the humerus. The bicipital groove has been proposed as a landmark for the prediction of humeral head retrotorsion. We hypothesized that a novel method based on bilateral registration of the bicipital groove yields an accurate approximation of the premorbid anatomy of the proximal part of the humerus. METHODS Three-dimensional (3D) triangular surface models were created from computed tomographic data of 100 paired humeri (50 cadavers). Segments of the distal part of the humerus and the humeral shaft of prespecified lengths were defined. A surface registration algorithm was applied to superimpose the models onto the mirrored contralateral humeral model based on the defined segments. We evaluated the 3D proximal humeral contralateral registration (p-HCR) errors, defined as the difference in 3D rotation of the humeral head between the models when superimposed. For comparison, we quantified the landmark-based retrotorsion (LBR) error, defined as the intra-individual difference in retrotorsion, measured with a landmark-based 3D method. RESULTS The mean 3D p-HCR error using the most proximal humeral shaft (bicipital groove) segment for the registration was 2.8° (standard deviation [SD], 1.5°; range, 0.6° to 7.4°). The mean LBR error of the reference method was 6.4° (SD, 5.9°; range, 0.5° to 24.0°). CONCLUSIONS Bilateral 3D registration of the bicipital groove is a reliable method for approximating the premorbid anatomy of the proximal part of the humerus. CLINICAL RELEVANCE The accurate approximation of the premorbid anatomy is a key for the successful restoration of the premorbid anatomy of the proximal part of the humerus

The Possibilities of Personalized 3D Printed Implants—A Case Series Study

Background and Objectives: Following the most recent software and 3D printing developments, the use of personalized 3D printed orthopedic implants for treatment of complicated surgical cases has gained more popularity. Today, orthopedic problems that cannot be solved with standard implants may be effectively addressed using personalized prostheses. The aim of this study is to present the designing, modeling and production stages of four different personalized 3D printed prostheses and their application in clinical cases of patients who underwent treatment in various anatomical locations with a precisely specified indication for implantation. Materials and Methods: Based on computed tomography scanning, personalized 3D printed prostheses were designed, produced and used in four patients within a period of three to five days after injury or admission. Results: Early term follow-ups demonstrated good to excellent results. Conclusions: Personalized 3D printed prostheses offer an opportunity for a treatment of choice and provide good anatomical and functional results, shortened surgical time, less complications, and high satisfaction in patients with appropriate indications. The method should be considered primarily for patients with large bone defects, or such indicated for resection. Personalized 3D printed prostheses have the potential to become more common and beneficial in the future