Standard surgical repair of intertrochanteric hip fractures requires accurate placement of a wire across the fracture using static fluoroscopic images. Few practice methods exist for perfecting this wire navigation skill outside the operating room. The objective of this research is to further understand skill development for orthopaedic drilling using a validated simulator, enabling more effective instruction and training. This includes the investigation of the relationship between practice and skill acquisition in conjunction with specific differences between experts and novices. This work details the creation and validation of an augmented reality wire navigation simulator for training orthopaedic drilling. This novel augmented reality simulator combines real-world objects, such as a surgical drill and synthetic bone, with virtually generated, radiation-free radiographic imaging. The central hypothesis is that an augmented reality wire navigation simulator will demonstrate construct validity and improve orthopaedic drilling skill through simulation training. This work identifies the differentiation of skill between experienced surgeons and novices completing the wire navigation task, demonstrating construct validity for the developed simulator. It also demonstrates that experienced surgeons are more accurate than novices in orthopaedic drilling (F(2, 39) = 3.721, p = 0.033). This provides evidence supporting the simulator's construct validity and value as a training and assessment tool in wire navigation of the proximal femur. Although the study was unsuccessful in providing sufficient evidence that training on the simulator directly transfers to more realistic drilling tasks, it revealed several discoveries about acquiring wire navigation skill. This work establishes a relationship between skill acquisition and practice for the wire navigation task. This learning curve shows that skill acquisition occurs much more slowly in wire navigation than previously assumed. The wire accuracy (i.e., tip-apex distance) is predicted to improve 0.1 to 0.3 millimeters with each successive practice repetition of the wire navigation task (95% CI, p < 0.001). In addition, the time to complete wire navigation improves between 0.4 and 2.0 seconds each subsequent practice trial (95% CI, p < 0.001). The developed simulator also identified several flaws in novice technique. First, novices do not account for the anteversion of the femoral neck indicating that the inclination angle is difficult for novices to understand and accurately drill from radiographic images. Another discovered flaw of novice orthopaedic residents is their lack of ability to accurately estimate distances in radiographic images. Novices were found to incorrectly estimate the wire accuracy by an average of 12.4 millimeters. Overall, this work establishes new findings, which can be used for future simulation development and coaching, enabling safer, more effective training methods for surgical residents.

Adequately assessing injury severity is critical in treating articular fractures. Severity assessment is used to inform clinical and surgical decision making through anticipation of patient outcomes. The assessments generally involve interpreting radiographs or CT image data. In recognition of the poor reliability of existing clinical severity assessments, objective severity metrics have been developed that are firmly rooted in mechanics and provide capable alternatives for use in research, where reliable data is paramount. Their broader clinical utility remains to be established. An existing CT-based method for determining the energy expended in a bone fracture was extended to facilitate its use in more fracture types. Its utility in different articular joints was evaluated. Specifically, the severities of articular fractures of the proximal tibia (plateau), of the distal tibia (plafond), and of the calcaneus were compared with present clinical severity metrics, patient outcomes, and/or surgeon rankings of severity. Differences in the fracture energies in the different joints were also compared. The objective fracture energy metric compared favorably with present clinical severity metrics. The fracture energies for fractures of the tibial plateau had between 71% and 78% concordance with surgeon rankings of severity. The calcaneal fracture energies had a 75% concordance with the present clinical standard. Fracture energy was also predictive of later radiographic indicators of post-traumatic osteoarthritis. The fracture energy metric is a capable tool for analyzing fracture severity in various joints. Fracture energy correlated well with outcomes and present clinical gold standards for severity assessment. The methods for assessing fracture energy described are highly useful for orthopaedic research and have potential as an important clinical tool.

Though the literature contains many computational models studying RSA, very few utilize finite element analysis to study stresses in the implant and the surrounding bone. The introductions section shows that many parameters (center of rotation lateralization, center of rotation superior or inferior position, tilt of the cut glenoid surface, glenosphere shape design, glenosphere size, humeral design, notch severity, etc.) have been studied independently utilizing many different methods (finite element modeling and non-FE computational modeling). However, the introduction section also detailed the current limitations in modern modeling as well as many examples of the heights to which finite element modeling can be taken to study RSA. Using these limitations as guidelines, the goal of this project is to create a robust FE model of RSA to study the effect of lateralization on scapular notching and shoulder function. In the following chapters, the development of the model is detailed. In addition, results produced by the incrementally advanced models are shown. In Chapter 2, the initial finite element model encompassing scapular and RSA hardware geometry is described. Chapter 3 contains description of incremental changes to the model including humeral geometry and muscle element incorporation. An anatomically realistic configuration of the finite element model with increased functionality is detailed in Chapter 4. Finally, Chapter 5 discusses the assets and limitations of the current model as a platform for future research. In addition, a proposed validation protocol is presented.

Transtibial stump volume can change dramatically postoperatively and jeopardise prosthetic fitting. Differences between individuals make it hard to give general recommendations of when to fit with a definitive prosthesis. Measuring the stump volume on every patient could solve this, but most methods for volume assessments are too complicated for clinical use. The aim of this study was to evaluate accuracy and intra- and interrater precision of a method to estimate stump volume from circumferential measurements. The method approximates the stump as a number of cut cones and the tip as a sphere segment. Accuracy was evaluated theoretically on six scanned stump models in CAPOD software and manually on six stump models. Precision was evaluated by comparing measurements made by four CPOs on eight stumps. Measuring devices were a wooden rule and a metal circumference rule. The errors were estimated with intraclass correlation coefficient (ICC), where 0,85 was considered acceptable, and a clinical criterion that a volume error of ±5% was acceptable (5% corresponds to one stocking). The method was accurate on all models in theory but accurate on only four models in reality. The ICC was 0,95-1,00 for intrarater precision but only 0,76 for interrater precision. Intra- and interrater precision was unsatisfying when using clinical criteria. Variations between estimated tip heights and circumferences were causing the errors. The method needs to be developed and is not suitable for stumps with narrow ends. Using a longer rule (about 30 cm) with a set square end to assess tip heights is recommended to improve precision. Using a flexible measuring-tape (possible to disinfect) with a spring-loaded handle could improve precision of the circumferential measurements.

<p>Transtibial stump volume can change dramatically postoperatively and jeopardise prosthetic fitting. Differences between individuals make it hard to give general recommendations of when to fit with a definitive prosthesis. Measuring the stump volume on every patient could solve this, but most methods for volume assessments are too complicated for clinical use.</p><p>The aim of this study was to evaluate accuracy and intra- and interrater precision of a method to estimate stump volume from circumferential measurements. The method approximates the stump as a number of cut cones and the tip as a sphere segment.</p><p>Accuracy was evaluated theoretically on six scanned stump models in CAPOD software and manually on six stump models. Precision was evaluated by comparing measurements made by four CPOs on eight stumps. Measuring devices were a wooden rule and a metal circumference rule. The errors were estimated with intraclass correlation coefficient (ICC), where 0,85 was considered acceptable, and a clinical criterion that a volume error of ±5% was acceptable (5% corresponds to one stocking).</p><p>The method was accurate on all models in theory but accurate on only four models in reality. The ICC was 0,95-1,00 for intrarater precision but only 0,76 for interrater precision. Intra- and interrater precision was unsatisfying when using clinical criteria. Variations between estimated tip heights and circumferences were causing the errors.</p><p>The method needs to be developed and is not suitable for stumps with narrow ends. Using a longer rule (about 30 cm) with a set square end to assess tip heights is recommended to improve precision. Using a flexible measuring-tape (possible to disinfect) with a spring-loaded handle could improve precision of the circumferential measurements.</p>

Reverse shoulder arthroplasty (RSA) is a joint replacement procedure used mainly to treat patients with severe shoulder osteoarthritis combined with massive rotator cuff tears. It involves reversing the `ball and socket' orientation of the glenohumeral joint in the shoulder. While RSA has been largely successful in treating pain and improving function in these patients, complication rates remain high. Many of these complications, including joint instability and scapular notching (excessive bone wear), are caused or exacerbated by impingement of the humerus or the humeral component against the scapula. Adduction deficit refers to a patient's inability to fully adduct the arm due to impingement. Minimizing adduction deficit may improve RSA patients' functional outcomes. An existing mechanical shoulder simulator was further developed to model glenohumeral range of motion in RSA. The three heads of the deltoid were modelled using polyethylene cable and electric linear actuators with inline load cells. RSA components were implanted in Sawbones scapula and humerus bone models. The scapula was fixed in the frame of the simulator. Triads of optical tracking markers were attached to the humerus and simulator frame and used to track segment motion. A data analysis technique was developed to determine when joint impingement occurred. The convex and concave surfaces of the glenoid and humeral components were digitized, and a least-squares sphere fit was used to find their centres. The distance between these centres was then calculated during passive abduction and adduction of the humerus, and labeled d_GH. Impingement onset was defined as the point where d_GH was five standard deviations above its baseline value, indicating that the components were no longer concentric. This technique was used to determine the effects of humeral neck-shaft angle, socket depth, glenosphere diameter and eccentricity on range of motion and adduction deficit. A retentive humeral cup depth increased adduction deficit by 14 degrees and reduced range of motion by 26 degrees. A decreased neck-shaft angle reduced adduction deficit by 10 degrees but had little effect on overall range of motion. Diameter and eccentricity had no effect on either measure. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2014-04-03 13:34:07.404

Femoral shaft fractures are commonly encountered in orthopaedics and are typically treated using intramedullary (IM) nailing under fluoroscopic guidance. Inaccuracies in the location of the entry point of the nail and the alignment of the reduced fracture are not uncommon during this procedure. This can greatly increase the risk of iatrogenic fractures, malunions and, potentially, secondary degenerative joint disease. Fluoroscopy-based computer-assisted navigation workflows have been developed but are, as yet, not widely used. As such, there is a need to investigate the performance of these systems as well as the possibility of using newer imaging methods to enhance the reduction accuracy. This body of work investigated the impact of off-angle fluoroscopic images on the accuracy and precision of the selection of the entry points used in IM nailing and found that, while images were considered to be clinically acceptable, they resulted in large deviations in the selection of the entry point. Although higher precision was achieved with navigation, it did not improve the accuracy. This work extended the investigation of off-angle images by investigating the impact of the variation in the landmarks used by current navigation methods on quantification of femoral anteversion. The observed landmark variations were propagated through the calculation of femoral anteversion and yielded errors exceeding current clinical tolerances. As an alternative to fluoroscopy, this work developed two, semi-automated algorithms to quantify femoral shaft fracture alignment in six degrees of freedom (6DOF) based on a single, intraoperative cone-beam CT scan. Both algorithms were able to accurately quantify malalignment in all 6DOF with high repeatability and limited user interaction over a range of complex femoral shaft fractures, even in cases with severe comminution. The time requirements for the utilization of these algorithms were reasonable with respect to the time required for current, fluoroscopy-based navigation. Therefore, both of these algorithms would provide an efficient, robust and accurate alternative for the quantification of malalignment in 6DOF. Such an accurate and robust quantification of malalignment, when paired with the high precision tracking in current navigation systems, may enable the improvement of reduction accuracy in the treatment of complex femoral shaft fractures.

Femoral shaft fractures are commonly encountered in orthopaedics and are typically treated using intramedullary (IM) nailing under fluoroscopic guidance. Inaccuracies in the location of the entry point of the nail and the alignment of the reduced fracture are not uncommon during this procedure. This can greatly increase the risk of iatrogenic fractures, malunions and, potentially, secondary degenerative joint disease. Fluoroscopy-based computer-assisted navigation workflows have been developed but are, as yet, not widely used. As such, there is a need to investigate the performance of these systems as well as the possibility of using newer imaging methods to enhance the reduction accuracy. This body of work investigated the impact of off-angle fluoroscopic images on the accuracy and precision of the selection of the entry points used in IM nailing and found that, while images were considered to be clinically acceptable, they resulted in large deviations in the selection of the entry point. Although higher precision was achieved with navigation, it did not improve the accuracy. This work extended the investigation of off-angle images by investigating the impact of the variation in the landmarks used by current navigation methods on quantification of femoral anteversion. The observed landmark variations were propagated through the calculation of femoral anteversion and yielded errors exceeding current clinical tolerances. As an alternative to fluoroscopy, this work developed two, semi-automated algorithms to quantify femoral shaft fracture alignment in six degrees of freedom (6DOF) based on a single, intraoperative cone-beam CT scan. Both algorithms were able to accurately quantify malalignment in all 6DOF with high repeatability and limited user interaction over a range of complex femoral shaft fractures, even in cases with severe comminution. The time requirements for the utilization of these algorithms were reasonable with respect to the time required for current, fluoroscopy-based navigation. Therefore, both of these algorithms would provide an efficient, robust and accurate alternative for the quantification of malalignment in 6DOF. Such an accurate and robust quantification of malalignment, when paired with the high precision tracking in current navigation systems, may enable the improvement of reduction accuracy in the treatment of complex femoral shaft fractures.

The way surgical trainees acquire technical skills is changing in modern surgical training programmes: simulation is proposed as a key part of those changes. Arthroscopy is a surgical technique that is increasing in both incidence and technical complexity; where simulation is becoming common, but evidence is limited. Real-world performance improvements can be measured following simulation training in other fields, but equivalent measures of intra-operative performance are inadequate. Thus, although surgical simulation is popular and improves simulated performance, there is little objective evidence that it improves intra-operative performance. The original contribution of this thesis is to objectively demonstrate the transfer of simulation training into improved intra-operative technical skills. To achieve this, a systematic literature review investigated the quantitative metrics currently used to measure arthroscopic performance, identifying wireless motion analysis as a potential method to assess performance intra-operatively. Motion analysis is a recognised objective method to measure surgical activity which correlates with surgical experience, so wireless motion analysis was validated against a wired motion analysis method commonly used in simulation but not feasible for intra-operative use. Wireless motion analysis metrics were further validated with a simulated arthroscopy list: this environment allowed deliberate practice of arthroscopic sub-skills with proximate feedback for independent practice. This simulated arthroscopy list with wireless motion analysis was used in two randomised studies: the penultimate study of this thesis investigated the impact of simulated practice on the arthroscopic learning curve and showed that performance improved rapidly with independent practice but was not modified by feedback, while the final study investigated additional simulation practice during early surgical training, and objectively demonstrated that additional simulation training improved intra-operative performance compared to traditional training alone. This thesis is the first to objectively show that simulation affects intra-operative behaviour. It sets the groundwork for further investigations into efficient, cost-effective simulation and the impact of simulation training on patient outcomes.

INTRODUCTION: Osteochondritis dissecans (OCD) of the capitellum is a focal condition affecting the articular cartilage and subchondral bone, typically in adolescent athletes. Limited data exists regarding the indications and expected outcomes of the various treatment methods of capitellar OCD, and the optimal treatment strategy remains controversial. Risks of progressive capitellar OCD include osteoarthritic changes and permanent elbow disability. STUDY AIMS: The objective of this literature review is to assess the data and the conclusions to be drawn from the existing literature on the differential indications for the various treatment options for capitellar OCD, using low-level meta-analysis and qualitative observations, to suggest a course of future study with the purpose of clarifying the differential treatment indications and improving the care of capitellar OCD patients. The most recent 10 years (2004-2014) of data are the focus, in order to evaluate the most modern indications, surgical techniques, surgical skills, and clinical outcomes. DISCUSSION OF PUBLISHED DATA: Ultrasound reportedly offers a high predictive value for screening baseball players for capitellar OCD, although sensitivity, specificity, and cost-effectiveness are unknown. Plain radiographs and magnetic resonance imaging (MRI) are useful diagnostic resources for making the decision to operate, but their sensitivities and specificities are imperfect. Evidence suggest that early stage OCD in physically immature patients may recover with non-operative management, while advanced stage OCD in older patients will likely achieve a better recovery with operative management. Risk factors for poor outcomes following surgical management of capitellar OCD may reportedly include patient age, physical maturity, athletic competition level, large lesion diameter and thickness, and lateral lesion location. The advantages of removal, debridement, and marrow stimulation techniques include the minimal invasiveness associated with arthroscopy. Successful fragment fixation can preserve normal articular properties, but may risk implant complications and secondary surgeries. Mosaicplasty is frequently suggested when patient or lesion characteristics seem to preclude other surgical methods, or when prior surgical treatment attempts fail, but disadvantages of mosaicplasty include the technical complexity of the procedure and the risk of donor site morbidity. CONCLUSIONS: The capitellar OCD literature has accumulated a wealth of level IV case series reporting generally satisfactory short-term results of the various surgical options. There is little need for more descriptive literature on this topic at this time. Modern treatment strategies are incomplete and poorly defined, based upon the suggestions of small case series offering disorganized, low-quality data. A study of the cost-effectiveness of ultrasound screening in high-risk athletes would be useful. A large, comparative case-control study or prospective cohort study of higher methodological quality and better standardization is needed to advance the knowledge on this topic, and classification and regression tree analysis could be applied meaningfully. With more organized data and analysis, it will become easier to take a systematic approach to treating capitellar OCD, settle clinical controversy and improve patient outcomes.