Computer aided preoperative planning application for shoulder hemiarthroplasty

This paper describes a proposed CAD graphics application that analyze digital radiography image for preoperative surgery in shoulder hemiarthroplasty.The purpose of designing this application is to aid orthopedic surgeon in preoperative planning phase before surgery, in terms of selecting suitable implant and manipulating the digital radiograph by using various facilities or tools available in the application. Therefore, digital templating and image processing play important roles in this research. Basically this application will support a few types of image file including jpg, gif, bmp and etc to be loaded. It will allow image enhancement and also enable measurement tools to be used by surgeon during the preoperative phase. A user will only need to do 5 simple steps in order to get the appropriate template and finally generate reports that he requires

Development and Implementation of a Computational Modeling Tool for Evaluation of THA Component Position

The human body is a complicated structure with muscles, ligaments, bones, and joints. Modeling human body with computational tools are becoming a trend [1]. More importantly, using computational tools to evaluate human body is a non-invasive technique that could help surgeons and researchers evaluate implant products [2]. Therefore, the development of a model which can analyze both implant sizing suggestion and kinematics of subject specific data could prove valuable. For total hip arthroplasty, one common complication is in vivo separation and dislocation of the femoral head within the acetabular cup [3] [4]. Developing a successful computational tool to address this issue includes developing a dynamic model of hip joint, implementing implant sizing suggestion algorithms and computing component alignments. Due to advancement in technology, the current focus has been to develop patient-specific solutions, a combined program of both hip model and implant suggestion model has been developed. In this dissertation, the primary objective is to develop a fully functional hip analysis software that not only can suggestion and template the implant sizing and position, but the software can also utilize the patient specific data to run simulation with different activities. The second objective of this dissertation is to conduct hip analysis studies using hip analysis software. Overall, the results in this dissertation discuss the effect of different stem positions and surgeon preferences on the outcome of the Total Hip Arthroplasty

The importance of biomechanical restoration for total hip arthroplasty

Total hip arthroplasty (THA) has become a safe and very successful surgical intervention. A vast majority of patients get their expectations met. Improvement of materials, implant designs, and surgical techniques, have extended prosthetic survival. However, inferior placement and sizing of a hip prosthesis are known to increase the risk of mechanical failure, wear, and early loosening as well as patient dissatisfaction. The main objective of this thesis was to evaluate the importance of improved biomechanical restoration for the function and survival of THA, as well as finding ways of achieving this improvement. We used radiostereometry (RSA), low dose computer tomography (CT) for 3D measurements, 3D templating, prosthetic modularity, and 3D gait analysis, together with patient-reported outcomes. We found a strong correlation between initial postoperative femoral neck anteversion (FNA) and subsequent posterior rotation and loosening of cemented stems. Our 3D measurement techniques showed near-perfect inter- and intraobserver agreements regarding our femoral offset (FO), acetabular offset (AO), and global offset (GO) measurements. We did not see any differences in RSA migration between uncemented modular and standard stem types, both stabilised well with good migration pattern. Postoperative FNA and FO/AO quota had no impact on uncemented stem migration, maybe due to the study being underpowered. The standard stem tended to result in insufficient GO, whereas the modular stem did not. 3D templating was superior in the correct prediction of the final stem size and neck, but 2D templating overestimated stem-size and underestimated neck-length. There was no statistically significant difference regarding cup size predictions. We found an unexpected progressive varus deformation, with concomitant corrosion-related cobalt ion release, from the modular stem-neck junction. However, the ion-concentrations did not correlate with adverse local tissue reaction (ALTR) as measured with MRI up to 8 years. Biomechanical restoration during THA does positively impact the quality of postoperative overall gait pattern, with faster walking speed and with less trunk lean over the affected side. Increased FNA was associated with increased internal hip rotation during walking. An increase in external hip adduction moments was, on the other hand, not associated with a change in FO/AO quota but with a more upright walking position and increased walking speed.Biomechanical restoration is important for THA and our studies confirm the need for precise measuring- and evaluation-tools for this kind of research

Quantitative fit analysis of acromion fracture plating systems using three-dimensional anatomical modelling

Background Displaced acromial fractures are challenging to treat. Complex bony anatomy, variable fracture morphology and limitations of available implants present challenges in achieving favourable surgical outcomes. We determined to what extent currently available scapular and clavicular plating systems are able to provide adequate fixation options. Methods Patients presenting to an urban trauma centre with acromial fractures sustained from blunt trauma between 2012 and 2016 were identified (n = 15, 14M / 1F). The fracture patterns were categorized according to location (Type I = 13%, Type II = 27%, Type III = 60%). Computed Tomography (CT) scans were reconstructed to produce three-dimensional (3D) printed anatomical models on which a quantitative fit analysis was performed. Measurements were performed twice, by five separate observers, with fit graded as anatomical fit ( 2mm) or no-fit. Results The anterior clavicle 6 hole plate fitted best in 45.7% of cases. Acromial plates only achieved 27.3%. The acromion short plate together with the lateral clavicle short plates performed the best in Type II fractures. An inter-observer intraclass correlation coefficient (ICC) agreement of 0.974 was obtained. Conclusion The available commercial acromial plating system fails to provide adequate congruency and fit for fixation. Clavicular plates were superior alternative implants. 3D printed anatomical models can be used effectively to assist in templating implants preoperatively

Clinical and radiological aspects of traumatic pelvic ring injury

Epidemiological data regarding High-Energy Traumatic Pelvic Ring Injury in Sweden was missing. Further, there was no data regarding current knowledge and level of experience of Swedish first line trauma officers about the management of traumatic pelvic ring injury. While conventional X-ray has been widely criticized as an optimal tool in assessment of pelvic ring injuries, a practical substitute has not been proposed. We planned to study epidemiological aspects of High Energy Traumatic Pelvic Ring Injury using data from the Karolinska Trauma Center. To assess first line trauma medical officer’s knowledge and level of experience regarding acute management of pelvic trauma. To investigate alternative practical options instead of conventional X-ray during the treatment of pelvic fractures. We used data from the Swedish National Trauma Registry (SweTrau). We used the Karolinska University Hospital´s Patient Notes and PACS. We used a questionnaire in order to assess Swedish trauma unit’s medical officers about acute management of pelvic trauma. We further used three dimensional models for image fusion and motion analysis in order to investigate symmetry of human pelvis and to investigate a pelvic fracture model. We found that the incidence of High Energy Traumatic Pelvic Ring Injury was about 3.5/100 000 inhabitants per year in Stockholm. The 30-day mortality was 7.8% and the 1 year mortality was 9%. The main cause of mortality was traumatic brain injury. Intentional injuries had a mortality rate of 15%. The reoperation frequency was 22%. Main cause of reoperation was due to metalwork problems, and a majority of them were potentially avoidable. We found that a majority of the Swedish first line trauma officers were aware of presence of a pelvic binder in their department and knew how to apply it, while there was more experience in the university hospitals. There was a general misconception regarding limitation of pelvic binders as 55% believed that a pelvic binder can stop an arterial bleeding. We were further able to show that human hemi pelvises are symmetrical and the 3D images of the contralateral hemi pelvis can be used for pre-operative templating. We were able to show that using fusion of serial 3D images of a pelvic model, translations of ±0.2 mm and rotations of ±0.2° could be detected. We can hereby conclude that monitoring 30-day mortality seems enough while studying high energy pelvic injuries. Intentional injuries need further future studies as per high mortality rate. Reoperation frequency following fixation of disrupted high energy pelvic fractures is high and needs addressing and early detection. Limitations of pelvic binders should be addressed during the trauma courses. Low dose CT-scan together with serial image fusion can be a future substitute for conventional X-ray. Human hemi pelvises are symmetrical and the contralateral side can be used for templating

A 3D computed tomography based tool for orthopedic surgery planning

Series : Lecture notes in computational vision and biomechanics, vol. 19The preparation of a plan is essential for a surgery to take place in the best way possible and also for shortening patient’s recovery times. In the orthopedic case, planning has an accentuated significance due to the close relation between the degree of success of the surgery and the patient recovering time. It is important that surgeons are provided with tools that help them in the planning task, in order to make it more reliable and less time consuming. In this paper, we present a 3D Computed Tomography based solution and its implementation as an OsiriX plugin for orthopedic surgery planning. With the developed plugin, the surgeon is able to manipulate a three-dimensional isosurface rendered from the selected imaging study (a CT scan). It is possible to add digital representations of physical implants (surgical templates), in order to evaluate the feasibility of a plan. These templates are STL files generated from CAD models. There is also the feature to extract new isosurfaces of different voxel values and slice the final 3D model according to a predefined plane, enabling a 2D analysis of the planned solution. Finally, we discuss how the proposed application assists the surgeon in the planning process in an alternative way, where it is possible to three-dimensionally analyze the impact of a surgical intervention on the patient.(undefined

Development and Implementation of a Computational Surgical Planning Model for Pre-Operative Planning and Post-Operative Assessment and Analysis of Total Hip Arthroplasty

Total hip arthroplasty (THA) is most often used to treat osteoarthritis of the hip joint. Due to lack of a better alternative, newer designs are evaluated experimentally using mechanical simulators and cadavers. These evaluation techniques, though necessary, are costly and time-consuming, limiting testing on a broader population. Due to the advancement in technology, the current focus has been to develop patient-specific solutions. The hip joint can be approximated as encompassing a bone socket geometry, and therefore the shapes of the implant are well constrained. The variability of performance after the surgery is mostly driven by surgical procedures. It is believed that placing the acetabular component within the “safe zone” will commonly lead to successful surgical outcomes [1]. Unfortunately, recent research has revealed problems with the safe zone concept, and there is a need for a better tool which can aid surgeons in planning for surgery.With the advancement of computational power, more recent focus has been applied to the development of simulation tools that can predict implant performances. In this endeavor, a virtual hip simulator is being developed at the University of Tennessee Knoxville to provide designers and surgeons alike instant feedback about the performance of the hip implants. The mathematical framework behind this tool has been developed.In this dissertation, the primary focus is to further expand the capabilities of the existing hip model and develop the front-end that can replicate a total hip arthroplasty surgery procedure pre-operatively, intra-operatively, and post-operatively. This new computer-assisted orthopaedic surgical tool will allow surgeons to simulate surgery, then predict, compare, and optimize post-operative THA outcomes based on component placement, sizing choices, reaming and cutting locations, and surgical methods. This more advanced mathematical model can also reveal more information pre-operatively, allowing a surgeon to gain ample information before surgery, especially with difficult and revision cases. Moreover, this tool could also help during the implant development design process as designers can instantly simulate the performance of their new designs, under various surgical, simulated in vivo conditions