Early Development of Total Hip Replacement

Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone. First published by the Wellcome Trust Centre for the History of Medicine at UCL, 2007. ©The Trustee of the Wellcome Trust, London, 2007. All volumes are freely available online at: www.history.qmul.ac.uk/research/modbiomed/wellcome_witnesses/Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Total hip replacement effectively began in the UK in 1938 and has led to widely used, commercially successful, mass-produced devices that relieve pain for an ever increasing period. The Witness Seminar, chaired by Mr Alan Lettin, discussed the remarkable postwar collaboration of British surgeons, engineers and manufacturing firms in the development of efficient alloys, surgical procedures, instruments and the implementation of clean, bacteria-reduced air in enclosed operating theatres, as illustrated by successful prostheses and techniques developed in Norwich (Kenneth McKee), Wrightington (Sir John Charnley), Stanmore (John Scales), Redhill (Peter Ring), and Exeter (Robin Ling and Clive Lee). Early failures - such as loosening from infection, osteolysis, and wear debris - stimulated the search for improved materials and fixation methods, as well as the addition of antibiotics to bone cement to reduce infection. National hip registers that record the survival of different implants were adopted in Europe in the 1970s (2003 in the UK), and they pinpoint the successful devices, as measured by survival and low rates of revision. An introduction to the volume by Dr Francis Neary and Professor John Pickstone, and appendices on materials by Professor Alan Swanson; on international standards by Mr Victor Wheble; and of details of selected prosthesis supplement the transcript. Contributors include: Lady Charnley, the late Mr Harry Craven, Mr Graham Deane, Professor Duncan Dowson, Mr Reg Elson, Dr Alex Faulkner, Professor Michael Freeman, Mrs Phyllis Hampson, Mr Kevin Hardinge, Mr Mike Heywood-Waddington, Mr John Kirkup, Mr Krishna (Ravi) Kunzru, Miss Betty Lee, Mr Alan Lettin (chair), Mr John Older, Mr John Read, Mr Peter Ring, Mr Ian Stephen, Mr Malcolm Swann, Professor Alan Swanson, Sir Rodney Sweetnam, Mr Keith Tucker, Mr Victor Wheble and Professor Michael Wroblewski. Reynolds L A, Tansey E M. (eds) (2007) Early development of total hip replacement, Wellcome Witnesses to Twentieth Century Medicine, vol. 29. London: The Wellcome Trust Centre for the History of Medicine at UCL.The Wellcome Trust Centre for the History of Medicine at UCL is funded by the Wellcome Trust, which is a registered charity, no. 210183

DEVELOPMENT OF A VIRTUAL TESTING LABORATORY FOR LOWER LIMB PROSTHESIS

The introduction of computer-aided tools into the product development process allows improving the quality of the product, evaluating different variants of the same product in a faster way and reducing time and costs. They can play a meaningful role also in designing custom-fit products (especially, those characterized by a tight interaction with the human body), increasing the comfort and improving people’s quality of life. This thesis concerns a specific custom-fit product, the lower limb prosthesis. It is part of a research project that aims at developing a new design platform centred on the digital model of the patient and his/her characteristics. The platform, named Prosthesis Virtual Laboratory (PVL), is being developed by the V&K Research Group (University of Bergamo) and integrates ICT tools and product-process knowledge. It provides two environments: one for prosthesis design (named Prosthesis Modelling Lab), both transfemoral and transtibial, and one for the prosthesis testing (named Virtual Testing Lab). The main objective has been to embed within the Virtual Testing Environment numerical simulation tools to analyse the interaction between the socket and the residual limb under different loading conditions, allowing the prosthetist to automatically run the simulation and optimize socket shape. Simulation tools, such as Finite Element Analysis (FEA), permit to predict the pressures at the interface socket-residual limb, evaluate the comfort of socket and validate the socket design before manufacturing phase. However, the diffusion of simulation tools in orthopaedic laboratories is strongly limited by the high level of competence required to use them. Furthermore, the implementation of the simulation model is time consuming and requires expensive resources, both humans and technological, especially onerous for small orthopaedic labs. To effectively employ the numerical analysis in prosthesis design, the simulation process has been automated and embedded within the virtual design platform. Therefore, in such a context, the specific scientific objectives have been to: • Critically analyse the state of the art with regard to methods and tools to evaluate socket-residual limb interaction. • Identify the key issues to automate the simulation activities. • Define a set of simulation rules and the Finite Element Analysis model. • Implement and integrate within the new design platform the automatic simulation procedure. • Test the integrated design platform with a case study. • Identify future development trends. Research activities have been organized into four main activities as follows. The first activity consisted in an extensive analysis of the last two decades State of the Art on numerical models adopted to study residual lower-limb and prosthetic socket interaction. Starting from literature, the key issues of the simulation process (e.g., geometric models reconstruction, materials characterization, simulation steps, and boundary conditions), the methodologies and procedures have been identified. Particular attention has been also paid to the parameters commonly adopted to evaluate socket comfort. This phase played a fundamental role since it constituted the basis for the implementation of the embedded simulation procedure. It also permitted to highlight that current finite element models are stand-alone and not integrated with prosthetic CAD or Digital Human Modelling (DHM) systems. In the second activity the tools and methods necessary to develop the embedded simulation module have been selected. By using these tools, it was possible to identify the simulation rules and the best practice procedures, which are fundamental to implement an automatic simulation module. Initially, the modelling tools have been considered since they provide the geometric models for the numerical analysis of the socket-residuum interaction and for the virtual gait analysis of the patient’s avatar. Then, particular attention has been paid on the choice of the FE solver, that has been made according to the results of preliminary FE models. They were implemented using two different solvers: Abaqus (commercial) and CalculiX (open-source). The latter has been experimented to verify the possibility to develop a design platform totally independent from commercial tools. However, according to the results, Abaqus has been chosen because it allows managing adequately simulation problems characterized by large deformations and difficult contact conditions, its results are comparable with those found in literature, and its scripting code does not require specific customization. The last considered tool was the Digital Human Modelling system (LifeMOD) since it permits to enhance the accuracy of the numerical analysis. By performing the gait simulation of the patient’s avatar, it provides the directions and the magnitude of forces and moments that act on the socket. The third activity consisted in defining the architecture of the simulation module, implementing the module and the interfaces with the socket CAD tool (namely Socket Modelling Assistant-SMA) to get the geometric models of the involved parts (socket and residual limb) and with the DHM system to acquire forces acting on the socket during patient’s walking. The simulation module has been implemented using the Python language and the integrated environment works as follows. Once the prosthetist has created the 3D socket model, SMA acquires the input for the analysis (e.g., residual limb length, patient’s weight, friction coefficient, material properties), and produces the files required to generate the FE model. Abaqus automatically generates the FE model without any human intervention, solves the analysis and generates the output file containing the pressure values. Results are imported in SMA and visualized with a colour map. SMA evaluates pressure distribution and highlights the areas that should be modified. Geometry modifications are needed in the areas where pressure exceeds the maximum value and are carried out automatically by the system or by the prosthetist using the virtual tools available in SMA. Then, the system re-executes the simulation. Through this iterative process of adjustments, the socket shape is modified and optimized in order to eliminate undercuts, minimize weight and, especially, distribute loads in the appropriate way so that they can be tolerated for the longest period of time. The fourth and last activity concerned the test and validation of the simulation module integrated within the new design platform, by considering a transfemoral patient. The new virtual process and the key issues of the simulation procedure have been tested starting from the patient’s data acquisition to the release of the socket using also data coming from the gait simulation with the DHM system. The geometric model of the residual limb has been reconstructed from MRI images and the socket has been modelled using SMA. Through an iterative process, the socket shape has been optimized until the pressure distribution on the residuum was consistent. Preliminary activity concerning the FE model validation has been performed comparing the pressure distribution experimentally acquired with pressure transducers over the residuum with the simulation results. To accomplish this task, the geometric model of the real socket has been acquired using reverse engineering techniques. Two numerical simulations have been implemented, they differ for the residuum geometric models adopted: from MRI and from 3D scanning. Preliminary results have been considered positive but improvements are necessary. As an example, some geometric inconsistencies, occurred during the acquisition of the geometric model of the residual limb, have reduced the accuracy of the final results. To complete the evaluation of the simulation model, a new residuum geometric model is needed and a refinement of the material model characterization is desirable. To conclude, the simulation module embedded within Virtual Testing Laboratory has improved the prosthesis development process with the goal of assessing and validating the socket shape under different load conditions (static or dynamic) before the manufacturing phase. The testing phase of the new procedure has demonstrated the feasibility of the virtual approach for lower limb prosthesis design. The tests carried out permitted to highlight necessary improvements and future developments, such as the definition of a protocol to acquire the residual limb through MRI and 3D scan, refinement of the FE model (e.g., non-linear viscoelastic behaviour for soft tissues, friction coefficients), parallel computing to improve simulation performances, open-source solvers to implement a design platform totally independent from commercial systems, and a massive test campaign involving transtibial and transfemoral patients to fully validate the FE model and the design platform

Novel computational protocol to support transfemoral prosthetic alignment procedure using machine learning techniques

The prosthetic alignment procedure considers biomechanical, anatomical and comfort characteristics of the amputee to achieve an acceptable gait. Prosthetic malalignment induces long-term disease. The assessment of alignment is highly variable and subjective to the experience of the prosthetist, so the use of machine learning could assist the prosthetist during the judgment of optimal alignment.Peer ReviewedPostprint (published version

A CAD Based Dynamic analysis approach to AK prosthesis design

Paper introduces dynamic simulation approach based on computer aided design (CAD), which was applied for development of a passive above-knee (AK) prosthesis to enable a one leg amputated patient with a reasonable size of stump. A locally-fabricated prosthetic knee was modified to develop a pneumatic damper-controlled AK prosthesis. Design studies were carried out to find center of gravity and moment of inertia of the assembly. CAD dynamic analysis was conducted on ProE software and the results were compared to actual swing time found experimentally in the lab. The leg was tested for validation on subjects with positive result

How a Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review of NIDILRR’s Rehabilitation Engineering Research Centers

Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their conception by a panel of the National Academy of Science in 1970, these centers were intended to take a “total approach to rehabilitation”, combining medicine, engineering, and related science, to improve the quality of life of individuals with a disability. Here, we review the scope, achievements, and ongoing projects of an unbiased sample of 19 currently active or recently terminated RERCs. Specifically, for each center, we briefly explain the needs it targets, summarize key historical advances, identify emerging innovations, and consider future directions. Our assessment from this review is that the RERC program indeed involves a multidisciplinary approach, with 36 professional fields involved, although 70% of research and development staff are in engineering fields, 23% in clinical fields, and only 7% in basic science fields; significantly, 11% of the professional staff have a disability related to their research. We observe that the RERC program has substantially diversified the scope of its work since the 1970’s, addressing more types of disabilities using more technologies, and, in particular, often now focusing on information technologies. RERC work also now often views users as integrated into an interdependent society through technologies that both people with and without disabilities co-use (such as the internet, wireless communication, and architecture). In addition, RERC research has evolved to view users as able at improving outcomes through learning, exercise, and plasticity (rather than being static), which can be optimally timed. We provide examples of rehabilitation technology innovation produced by the RERCs that illustrate this increasingly diversifying scope and evolving perspective. We conclude by discussing growth opportunities and possible future directions of the RERC program

A review of acetabular prostheses for total hip arthroplasty

This study explores the evolution, design, and clinical progress of contemporary prostheses used in orthopaedic reconstruction of the socket of the hip joint. A literature search was performed to study acetabular implants, as used in total hip arthroplasty. The history of the design of these implants is chronicled. Next, the anatomy of the acetabular region and the surgical technique performed to replace the hip socket are presented. A comprehensive discussion of the design features, rationale, and clinical results for commercially available cemented and cementless prostheses follows. Hydroxyapatite, a bioceramic which has just recently been approved for applications in total hip arthroplasty, is described, the coating process explained, and its clinical effects evaluated. Finally, the abnormal or deficient acetabulum is reviewed. Corrective implants and reconstructive techniques are described

Augmented interaction for custom-fit products by means of interaction devices at low costs

This Ph.D thesis refers to a research project that aims at developing an innovative platform to design lower limb prosthesis (both for below and above knee amputation) centered on the virtual model of the amputee and based on a computer-aided and knowledge-guided approach. The attention has been put on the modeling tool of the socket, which is the most critical component of the whole prosthesis. The main aim has been to redesign and develop a new prosthetic CAD tool, named SMA2 (Socket Modelling Assistant2) exploiting a low-cost IT technologies (e.g. hand/finger tracking devices) and making the user’s interaction as much as possible natural and similar to the hand-made manipulation. The research activities have been carried out in six phases as described in the following. First, limits and criticalities of the already available modeling tool (namely SMA) have been identified. To this end, the first version of SMA has been tested with Ortopedia Panini and the orthopedic research group of Salford University in Manchester with real case studies. Main criticalities were related to: (i) automatic reconstruction of the residuum geometric model starting from medical images, (ii) performance of virtual modeling tools to generate the socket shape, and (iii) interaction mainly based on traditional devices (e.g., mouse and keyboard). The second phase lead to the software reengineering of SMA according to the limits identified in the first phase. The software architecture has been re-designed adopting an object-oriented paradigm and its modularity permits to remove or add new features in a very simple way. The new modeling system, i.e. SMA2, has been totally implemented using open source Software Development Kit-SDK (e.g., Visualization ToolKit VTK, OpenCASCADE and Qt SDK) and based on low cost technology. It includes: • A new module to automatically reconstruct the 3D model of the residual limb from MRI images. In addition, a new procedure based on low-cost technology, such as Microsoft Kinect V2 sensor, has been identified to acquire the 3D external shape of the residuum. • An open source software library, named SimplyNURBS, for NURBS modeling and specifically used for the automatic reconstruction of the residuum 3D model from medical images. Even if, SimplyNURBS has been conceived for the prosthetic domain, it can be used to develop NURBS-based modeling tools for a range of applicative domains from health-care to clothing design. • A module for mesh editing to emulate the hand-made operations carried out by orthopedic technicians during traditional socket manufacturing process. In addition several virtual widgets have been implemented to make available virtual tools similar to the real ones used by the prosthetist, such as tape measure and pencil. • A Natural User Interface (NUI) to allow the interaction with the residuum and socket models using hand-tracking and haptic devices. • A module to generate the geometric models for additive manufacturing of the socket. The third phase concerned the study and design of augmented interaction with particular attention to the Natural User Interface (NUI) for the use of hand-tracking and haptic devices into SMA2. The NUI is based on the use of the Leap Motion device. A set of gestures, mainly iconic and suitable for the considered domain, has been identified taking into account ergonomic issues (e.g., arm posture) and ease of use. The modularity of SMA2 permits us to easily generate the software interface for each device for augmented interaction. To this end, a software module, named Tracking plug-in, has been developed to automatically generate the source code of software interfaces for managing the interaction with low cost hand-tracking devices (e.g., Leap Motion and Intel Gesture Camera) and replicate/emulate manual operations usually performed to design custom-fit products, such medical devices and garments. Regarding haptic rendering, two different devices have been considered, the Falcon Novint, and a haptic mouse developed in-house. In the fourth phase, additive manufacturing technologies have been investigated, in particular FDM one. 3D printing has been exploited in order to permit the creation of trial sockets in laboratory to evaluate the potentiality of SMA2. Furthermore, research activities have been done to study new ways to design the socket. An innovative way to build the socket has been developed based on multi-material 3D printing. Taking advantage of flexible material and multi-material print possibility, new 3D printers permit to create object with soft and hard parts. In this phase, issues about infill, materials and comfort have been faced and solved considering different compositions of materials to re-design the socket shape. In the fifth phase the implemented solution, integrated within the whole prosthesis design platform, has been tested with a transfemoral amputee. Following activities have been performed: • 3D acquisition of the residuum using MRI and commercial 3D scanning systems (low cost and professional). • Creation of the residual limb and socket geometry. • Multi-material 3D printing of the socket using FDM technology. • Gait analysis of the amputee wearing the socket using a markerless motion capture system. • Acquisition of contact pressure between residual limb and a trial socket by means of Teskan’s F-Socket System. Acquired data have been combined inside an ad-hoc developed application, which permits to simultaneously visualize pressure data on the 3D model of the residual lower limb and the animation of gait analysis. Results and feedback have been possible thanks to this application that permits to find correlation between several phases of the gait cycle and the pressure data at the same time. Reached results have been considered very interested and several tests have been planned in order to try the system in orthopedic laboratories in real cases. The reached results have been very useful to evaluate the quality of SMA2 as a future instruments that can be exploited for orthopedic technicians in order to create real socket for patients. The solution has the potentiality to begin a potential commercial product, which will be able to substitute the classic procedure for socket design. The sixth phase concerned the evolution of SMA2 as a Mixed Reality environment, named Virtual Orthopedic LABoratory (VOLAB). The proposed solution is based on low cost devices and open source libraries (e.g., OpenCL and VTK). In particular, the hardware architecture consists of three Microsoft Kinect v2 for human body tracking, the head mounted display Oculus Rift SDK 2 for 3D environment rendering, and the Leap Motion device for hand/fingers tracking. The software development has been based on the modular structure of SMA2 and dedicated modules have been developed to guarantee the communication among the devices. At present, two preliminary tests have been carried out: the first to verify real-time performance of the virtual environment and the second one to verify the augmented interaction with hands using SMA2 modeling tools. Achieved results are very promising but, highlighted some limitations of this first version of VOLAB and improvements are necessary. For example, the quality of the 3D real world reconstruction, especially as far as concern the residual limb, could be improved by using two HD-RGB cameras together the Oculus Rift. To conclude, the obtained results have been evaluated very interested and encouraging from the technical staff of orthopedic laboratory. SMA2 will made possible an important change of the process to design the socket of lower limb prosthesis, from a traditional hand-made manufacturing process to a totally virtual knowledge-guided process. The proposed solutions and results reached so far can be exploited in other industrial sectors where the final product heavily depends on the human body morphology. In fact, preliminary software development has been done to create a virtual environment for clothing design by starting from the basic modules exploited in SMA2

FEM Model an Effective Tool to Evaluate Von Mises Stresses in Shoulder Joint and Muscles for Adduction and Abduction

AbstractShoulder is one of the most complicated and critical joint. It consists of the clavicle, scapula and humerus. Studying individual functions of these structures is nearly unfeasible. In order to understand these relationships during different shoulder exercise, an attempt has been made to model, simulate and analyze the shoulder joint.The technique described in this paper utilizes the advanced 3D scanning; Computer Aided Design (CAD), DMU Kinematics Tool in CATIA V5 then Finite Element Analysis (FEA) to detect the stress points of the shoulder joints during adduction and abduction. FEM of the ligaments and the muscles are carried out using the hexa-penta mesh elements in Hyper Mesh and von mises stresses are analysed by LS DYNA software. The results for abduction and adduction are plotted and validated with the previous research papers as well as the limiting values of the different shoulder muscle for the range of motion 0° to 30°