Aims. The primary aim of the survey was to map the current provision of
Hip joint biomechanics can be altered by abnormal morphology of the acetabulum and/or femur. This may affect load distribution and contact stresses on the articular surfaces, hence, leading to damage and degradation of the tissue. Experimental hip joint simulators have been used to assess tribology of total hip replacements and recently methods further developed to assess the natural hip joint mechanics. The aim of this study was to evaluate articular surfaces of human cadaveric joints following prolonged experimental
The treatment of paediatric supracondylar humeral fractures is likely one of the first procedures involving X-ray guided wire insertion that trainee orthopaedic surgeons will encounter. Pinning is a skill that requires high levels of anatomical knowledge, spatial awareness, and hand-eye coordination. We developed a
Surgical trainees are finding it increasingly more challenging to meet operative requirements and coupled with the effects of COVID-19, we face a future of insufficiently trained surgeons. As a result, virtual reality (VR) simulator training has become more prevalent and whilst more readily accepted in certain arthroscopic fields, its use in hip arthroscopy (HA) remains novel. This project aimed to validate VR high-fidelity HA
Iliopsoas tendonitis occurs in up to 30% of patients after hip resurfacing arthroplasty (HRA) and is a common reason for revision. The primary purpose of this study was to validate our novel computational model for quantifying iliopsoas impingement in HRA patients using a case-controlled investigation. Secondary purpose was to compare these results with previously measured THA patients. We conducted a retrospective search in an experienced surgeon's database for HRA patients with iliopsoas tendonitis, confirmed via the active hip flexion test in supine, and control patients without iliopsoas tendonitis, resulting in two cohorts of 12 patients. The CT scans were segmented, landmarked, and used to simulate the iliopsoas impingement in supine and standing pelvic positions. Three discrete impingement values were output for each pelvic position, and the mean and maximum of these values were reported. Cup prominence was measured using a novel, nearest-neighbour algorithm. The mean cup prominence for the symptomatic cohort was 10.7mm and 5.1mm for the asymptomatic cohort (p << 0.01). The average standing mean impingement for the symptomatic cohort was 0.1mm and 0.0mm for the asymptomatic cohort (p << 0.01). The average standing maximum impingement for the symptomatic cohort was 0.2mm and 0.0mm for the asymptomatic cohort (p << 0.01). Impingement significantly predicted the probability of pain in logistic regression models and the
Abstract. Introduction. Knee arthroscopy can be used for ligamentous repair, reconstruction and to reduce burden of infection. Understanding and feeling confident with knee arthroscopy is therefore a highly important skillset for the orthopaedic surgeon. However, with limited training or experience, furthered by reduced practical education due to COVID-19, this skill can be under-developed amongst trainee surgeons. Methods. At a single institution, ten junior doctors (FY1 to CT2), were recruited as a part of a five, two-hour session, training programme utilising the Simbionix® ARTHRO Mentor knee arthroscopy simulator, supplemented alongside educational guidance with a consultant orthopaedic knee surgeon. All students had minimal to no levels of prior arthroscopic experience. Exercises completed included maintaining steadiness, image centering and orientation, probe triangulation, arthroscopic knee examination, removal of loose bodies, and meniscectomy. Pre and post-experience questionnaires and quantitative repeat analysis on
Introduction. Knee arthroscopy can be used for ligamentous repair, reconstruction and to reduce burden of infection. Understanding and feeling confident with knee arthroscopy is therefore a highly important skillset for the orthopaedic surgeon. However, with limited training or experience, furthered by reduced practical education due to COVID-19, this skill can be under-developed amongst trainee surgeons. Methods. At a single institution, ten junior doctors (FY1 to CT2), were recruited as a part of a five, two-hour session, training programme utilising the Simbionix® ARTHRO Mentor knee arthroscopy simulator, supplemented alongside educational guidance with a consultant orthopaedic knee surgeon. All students had minimal to no levels of prior arthroscopic experience. Exercises completed included maintaining steadiness, image centring and orientation, probe triangulation, arthroscopic knee examination, removal of loose bodies and meniscectomy. Pre and post experience questionnaires and quantitative repeat analysis on
Abstract. OBJECTIVES. Abnormal joint mechanics have been proposed as adversely affecting natural hip joint tribology, whereby increased stress on the articular cartilage from abnormal loading leads to joint degeneration. The aim of this project was to assess the damage caused by different loading conditions on the articular surfaces of the porcine hip joint in an experimental simulator. METHODS. Porcine hip joints were dissected and mounted in a single station hip simulator (SimSol, UK) and tested under loading scenarios (that corresponded to equivalent of different body mass index's’ (BMI) in humans), as follows:“Normal” (n=4), the loading cycle consisted of a simplified gait cycle based on a scaled version of a simplified twin-peak human gait cycle, the peak load was 900N (representative of a healthy BMI). Representative of an “Overweight” BMI (n=3), as the normal cycle with a peak load of 1,130N Representative of an “Obese” BMI (n=1), as the normal cycle with a peak load of 1,340N Tests were conducted at 1Hz for 14,400 cycles in Ringers solution; photogrammetry was used to characterise the appearance of the cartilage and labrum pre, during and post
Introduction. Derotation osteotomies are commonly performed in paediatric orthopaedic and limb reconstruction practice. The purpose of this study was to determine whether the use of a digital inclinometer significantly improves the accuracy in attaining the desired correction. Materials & Methods. We designed an electronic survey regarding derotation femoral osteotomy (DFO) including methods of intra-operative angular correction assessment and acceptable margins of error for correction. This was distributed to 28 paediatric orthopaedic surgeons in our region. A DFO model was created, using an anatomic sawbone with foam covering. 8 orthopaedic surgeons each performed two 30-degree DFOs, one using K-wires and visual estimation (VE), and the other using a Digital Inclinometer (DI). Two radiologists reported pre and post procedure rotational profile CT scans to assess the achieved rotational correction. Results. There was a 68% response rate to the survey. The most popular methods of estimating intra-operative correction were reported to be K-wires and rotation marks on bone. The majority of respondents reported that a 6–10 degree margin of error was acceptable for a 30-degree derotation. This was therefore set as the upper limit for acceptable error margin in the
We share our experiences in designing a complete simulator prototype and provide the technological basis to determine whether an immersive medical training environment for vertebroplasty is successful. In our study, the following key research contributions were realised: (1) the effective combination of a virtual reality surgical simulator and a computerised mannequin in designing a novel training setup for medical education, and (2) based on a user-study, the quantitative evaluation through surgical workflow and crisis
Paediatric musculoskeletal (MSK) disorders often produce severe limb deformities, that may require surgical correction. This may be challenging, especially in case of multiplanar, multifocal and/or multilevel deformities. The increasing implementation of novel technologies, such as virtual surgical planning (VSP), computer aided surgical
Introduction. Geometric variations of the hip joint can give rise to abnormal joint loading causing increased stress on the articular cartilage, which may ultimately lead to degenerative joint disease. In-vitro
Introduction. Loads acting on the knee are tied to the long term performance of implants, and are directly related to ligament function [1]. Previous work has used computational models coupled with optimization to estimate ligament properties based on experimental joint kinematics [2]. Our group recently utilized a similar optimization scheme that estimated ligament slack lengths based on experimental implant contact metrics [3]. A comparison with surgically relevant loading conditions that were excluded from the optimization would help establish the utility of the
Introduction. Total knee arthroplasty (TKA) prostheses are semi-constrained artificial joints. A well-functioning TKA prosthesis should be designed with a good balance between stability and mobility, meaning the femorotibial constraint of the artificial joint should be appropriate for the device's function. To assess the constraint behavior of a TKA prosthesis, physical testing is typically required, and an industrial testing standard has been developed for this purpose [1]. Computer
Summary Statement. The constraint behavior of total knee arthroplasty (TKA) prosthesis usually has to be physically tested. This study presents a computer
Introduction. Experimental wear
“Simulation”, “deliberate practice”, “rehearsal” have been used to describe safe acquisition and practice of skills before patient contact.
INTRODUCTION. While computational models have been used for many years to contribute to pre-clinical, design phase iterations of total knee replacement implants, the analysis time required has limited the real-time use as required for other applications, such as in patient-specific surgical alignment in the operating room. In this environment, the impact of variation in ligament balance and implant alignment on estimated joint mechanics must be available instantaneously. As neural networks (NN) have shown the ability to appropriately represent dynamic systems, the objective of this preliminary study was to evaluate deep learning to represent the joint level kinetic and kinematic results from a validated finite element lower limb model with varied surgical alignment. METHODS. External hip and ankle boundary conditions were created for a previously-developed finite element lower limb model [1] for step down (SD), deep knee bend (DKB) and gait to best reproduce in-vivo loading conditions as measured on patients with the Innex knee (. orthoload.com. ) (Figure1). These boundary conditions were subsequently used as inputs for the model with a current fixed-bearing total knee replacement to estimate implant-specific kinetics and kinematics during activities of daily living. Implant alignments were varied, including variation of the hip-knee-ankle angle-±3°, the frontal plane joint line −7° to +5°, internal-external femoral rotation ±3°, and the tibial posterior slope 5° and 0°. Through varying these parameters a total of 2464
Experimental
Objectives. Posterior condylar offset (PCO) and posterior tibial slope (PTS) are critical factors in total knee arthroplasty (TKA). A computational
With the advancement of the virtual technologies, three-dimensional surgical simulators are now possible. In this article, we describe an immersive
Data from the wait list management system and hospital databases was used to develop a computer model simulating the resource requirements required during patient flow into, through, and out of orthopaedic surgery for TKR, THR and knee arthroscopy. Results from the
Introduction. Total knee arthroplasty (TKA) is a well proven surgical procedure. Squat and gait motions are common activities in daily life. However, squat motion is known as most dissatisfying motion in activities in daily life after total knee arthroplasty (TKA). Dissatisfaction after TKA might refer to muscle co-contraction between quadriceps and hamstrings. The purposed of this study was to develop squat and gait
Aims. The aim of this study was to assess the current evidence relating
to the benefits of virtual reality (VR)
Skills
Skills
Objectives. Malrotation of the femoral component can result in post-operative complications in total knee arthroplasty (TKA), including patellar maltracking. Therefore, we used computational
Introduction. Fretting corrosion at the taper interface has been implicated as a possible cause of implant failure. Using in-vitro testing, fretting wear observed at tapers of retrieved implants may be reproduced (Marriott, EORS-2014). In order to reduce time and cost associated with experimental testing, a validated finite element method (FE) can be employed to study the mechanics at the taper. In this study we compared experimental and representative FE
Introduction. The number of young and more active patients requiring total knee replacement (TKR) is increasing. Preclinical evaluation and understanding the long-term failure of TKR is therefore important. Preclinical wear
The alignment of prostheses components has a major impact on the longevity of total knee protheses as it significantly influences the biomechanics and thus also the load distribution in the knee joint. Knee joint loads depend on three factors: (1) geometrical conditions such as bone geometry and implant position/orientation, (2) passive structures such as ligaments and tendons as well as passive mechanical properties of muscles, and (3) active structures that are muscles. The complex correlation between implant position and clinical outcome of TKA and later in vivo joint loading after TKA has been investigated since 1977. These investigations predominantly focused on component alignment relative to the mechanical leg axis (Mikulicz-line) and more recently on rotational alignment perpendicular to the mechanical axis. In general four different approaches can be used to study the relationship between implant position and knee joint loads: In anatomical studies (1), the influence of the geometrical conditions and passive structures can be analyzed under the constraint that the properties of vital tissue are only approximated. This could be overcome with an intraoperative load measurement approach (2). Though, this set up does not consider the influence of active structures. Although post-operative in vivo load measurements (3) provide information about the actual loading condition including the influence of active structures, this method is not applicable to investigate the influence of different implant positions. Using mathematical approaches (4) including finite element analysis and multi-body-modeling, prostheses positions can be varied freely. However, there exists no systematical analysis of the influence of prosthesis alignment on knee loading conditions not only in axial alignment along and rotational alignment perpendicular to the mechanical axis but in all six degrees of freedom (DOF) with a validated mathematical model. Our goal was therefore to investigate the correlation between implant position and joint load in all six DOF using an adaptable biomechanical multi-body model. A model for the
INTRODUCTION. Knee simulators are being used to evaluate wear. The current international standards have been developed from clinical investigations of the normal knee [1, 2] or from a single TKA patient [3, 4]. However, the forces and motions in a TKA patient differ from a normal knee and, furthermore, the resulting kinematic outcomes after TKA will depend on the design of the device [5]. Consequently, these standard tests may not recreate in-vivo conditions; therefore, the goal of this study was to perform a novel wear
Background. Rotational acetabular osteotomy (RAO) is an effective treatment option for symptomatic acetabular dysplasia. However, excessive lateral and anterior correction during the periacetabular osteotomy may lead to femoroacetabular impingement. We used preoperative planning software for total hip arthroplasty to perform femoroacetabular impingement
Abstract. Objectives. Evidence supporting the use of immersive virtual reality (iVR) training in orthopaedic procedures is rapidly growing. However, the impact of the timing of delivery of this training is yet to be tested. This study investigated whether spaced iVR training is more effective than massed iVR training for novices learning hip arthroplasty. Methods. 24 medical students with no hip arthroplasty experience were randomised to learning total hip arthroplasty using the same iVR
Aims. Mobile-bearing unicompartmental knee arthroplasty (UKA) with a flat tibial plateau has not performed well in the lateral compartment, leading to a high rate of dislocation. For this reason, the Domed Lateral UKA with a biconcave bearing was developed. However, medial and lateral tibial plateaus have asymmetric anatomical geometries, with a slightly dished medial and a convex lateral plateau. Therefore, the aim of this study was to evaluate the extent at which the normal knee kinematics were restored with different tibial insert designs using computational
Objectives. Preservation of both anterior and posterior cruciate ligaments in total knee arthroplasty (TKA) can lead to near-normal post-operative joint mechanics and improved knee function. We hypothesised that a patient-specific bicruciate-retaining prosthesis preserves near-normal kinematics better than standard off-the-shelf posterior cruciate-retaining and bicruciate-retaining prostheses in TKA. Methods. We developed the validated models to evaluate the post-operative kinematics in patient-specific bicruciate-retaining, standard off-the-shelf bicruciate-retaining and posterior cruciate-retaining TKA under gait and deep knee bend loading conditions using numerical
Objective: In Total Hip Arthroplasty, 2D template on Plain X-ray is usually used for preoperative planning. But deformity and contracture can cause malpositionning and measurement error. To reduce those problems, a 3D preoperative
Introduction. The purpose of this study was to experimentally evaluate impingement and dislocation of total hip replacements while performing dynamic movements under physiological-like conditions. Therefore, a hardware-in-the-loop setup has been developed, in which a physical hip prosthesis actuated by an industrial robot interacts with an in situ-like environment mimicked by a musculoskeletal multibody simulation-model of the lower extremity. Methods. The multibody model of the musculoskeletal system comprised rigid bone segments of the lower right extremity, which were mutually linked by ideal joints, and a trunk. All bone geometries were reconstructed from a computed tomography set preserving anatomical landmarks. Inertia properties were identified based on anthropometric data and by correlating bone density to Hounsfield units. Relevant muscles were modeled as Hill-type elements, passive forces due to capsular tissue have been neglected. Motion data were captured from a healthy subject performing dislocation-associated movements and were fed to the musculoskeletal multibody model. Subsequently, the robot moved and loaded a commercially available total hip prosthesis and closed the loop by feeding the physical contact information back to the
Introduction. Range of motion (ROM)
Introduction. Current work-hour restrictions and cost pressures have highlighted the limitations of apprenticeship-based learning, and led to the development of alternative methods to improve the skills of orthopaedic trainees outside of the clinical environment. These methods include using synthetic bones and simulators in the laboratory setting. Educational theory highlights the importance of context for effective learning, yet full-immersion
Hip resurfacing has many advantages such as proximal bone conservation and easy revision including conversion to total hip arthroplasty. The major complication in the hip resurfacing is notching at the lateral cortical bone and fracture of the neck. In this research, we simulated the range of direction of reaming without causing notch. One left femur model was used for the
Aim. The aim of this study is to evaluate the effect of three-dimensional (3D)
Introduction. Kinematics tracking is the process by which the motion of the joints is studied. This motion consists of relative rotation and translation of the joint bones. Joint motion analysis is used in diagnosis of joint pathology, as well as studying the normal joint function. Currently, fluoroscopy is used in joint kinematics tracking. We are researching the use of pulse-echo A-mode ultrasound for the bone motion tracking instead of the fluoroscopy to avoid its radiation. In this work we performed feasibility study using
Currently, standard total knee arthroplasty (TKA) procedures focus on axial and rotational alignment of the prosthesis components and ligament balancing. Even though TKA has been constantly improved, TKA patients still experience a significantly poorer functional outcome than total hip arthroplasty patients. Among others, complications can occur when knee kinematics (active/passive) after TKA do not correspond with the physiological conditions. We hypothesised that the Q-angle has a substantial impact on active joint kinematics and should be taken into account in TKA. The Q-angle can be influenced by the position of the tibial tuberosity (TT). A pathological position of the TT is commonly related to patellofemoral pain and knee instability. A clinically well accepted surgical treatment is the TT medialisation which causes a change in the orientation of the patella tendon and thus alters the biomechanics of the knee. If active and passive knee kinematics differs, this aspect should be considered for implant design and positioning. Therefore we investigated the sensitivity of active knee kinematics related to the position of the TT by using a complex multi-body model with a dynamic
Mechanical wear and corrosion lead to the release of metal particulate debris and subsequent release of metal ions at the trunnion-taper surface. In order to quantify the amount of volume loss to ultimate locations in the surrounding joint space, finite element analysis of the modular head-stem junction is being carried out. The key purpose being to determine a set of optimum design changes that offer the least material loss at the taper-trunnion junction using optimization algorithms such as the gradient based local search (Sequential Quadratic Programming–SQP) and global search (Non-Dominated Sorting Genetic Algorithm-II–NSGA-II). In a broader sense, the principal goal is to work toward the minimization of wear debris produced in the hip joint, thereby resulting in a longer prosthetic lifetime. A numerical approach that simulates wear in modular hip prostheses with due consideration to the taper-trunnion junction on metal-on-metal contacts is proposed. A quasi-static analysis is performed considering realistic loading stages in the gait cycle, and nonlinear contact analysis is to be employed. The technique incorporates a measured wear rate as an input to the finite element model. The
Introduction. Support cages are often used for reconstruction of acetabular bone defects in revision total hip arthroplasty. A Burch-Schneider cage is one of the most reliable systems that has shown good clinical results. It has an ischial flange and an iliac plate for screw fixation to the ilium. It is sometimes necessary to bend the flange or the plate to fit the shape of the peri-acetabulum. However, the frequency, indications, and characteristics of bending the flange or plate have not been reported. To clarify them, a
Experimental knee simulators for component evaluation or in vitro testing provide valuable insight into the mechanics of the implanted joint. The Kansas knee simulator (KKS) is an electro-hydraulic whole joint knee simulator, with five actuators at the hip, ankle and quadriceps muscle used to simulate a variety of dynamic activities in cadaveric specimens. However, the number and type of experimental tests which can feasibly be performed is limited by the need to make physical component parts, obtain cadaveric specimens and the substantial time required to carry out each test. Computational
Introduction. Total knee arthroplasty (TKA) has achieved excellent clinical outcomes and functional performances. However, there is a need for greater implant longevity and higher flexion by younger and Asian patients. We determined the relationship between mobility and stability of TKA product because they are essential for much further functional upgrading. This research evaluated the geometry characteristics of femorotibial surfaces quantitatively by measuring their force of constraint by computer
Mechanical loading is important to maintain the homeostasis of the intervertebral disc (IVD) under physiological conditions but can also accelerate cell death and tissue breakdown in a degenerative state. Bioreactor loaded whole organ cultures are instrumental for investigating the effects of the mechanical environment on the IVD integrity and for preclinical testing of new therapies under simulated physiological conditions. Thereby the loading parameters that determine the beneficial or detrimental reactions largely depend on the IVD model and its preparation. Within this symposium we are discussing the use of bovine caudal IVD culture models to reproduce tissue inflammation or matrix degradation with or without bioreactor controlled mechanical loading. Furthermore, the outcome parameters that define the degenerative state of the whole IVD model will be outlined. Besides the disc height, matrix integrity, cell viability and phenotype expression, the tissue secretome can provide indications about potential interactions of the IVD with other cell types such as neurons. Finally, a novel multiaxial bioreactor setup capable of mimicking the six degrees-of-freedom loading environment of IVDs will be introduced that further advances the relevance of preclinical ex-vivo testing.
Hip and knee wear simulators have been used by implant manufacturers and researchers for many years as a performance predictor and comparator for hip and knee implants. The clinical accuracy of these simulators in predicting wear depends heavily on the type of simulator as well as the methodology used. The joint lubricant used in the simulators is one crucial aspect that has been well studied in hip simulators. This study will compare the wear performance of a modern total knee replacement system using two commonly used simulator lubricants at various dilutions (Alpha Calf Serum and Bovine Calf Serum, Hyclone Labs). The Triathlon knee implant system (Stryker Orthopaedics) was used along with a six station knee wear simulator from MTS Systems to determine the effect of lubricant type and dilution. Wear rates were found to be dependent on the type and dilution of the lubricant. At 0g/L protein concentration (100% water) wear rates were 4.8mm3/million cycles (mc). With the introduction of Bovine serum, wear rates increase to a peak of 24mm3/mc at 5g/L of concentration. Increased concentration of Bovine serum resulted in a decrease of wear rates. Wear rates for Alpha serum peaked at 28mm3/mc at 20g/L concentration with decreased wear rates at higher concentrations. Knee implant wear performance is often characterized by wear