University Libraries Annual Report 2017

2017 Annual Report from the University of Denver, University Libraries. The annual report highlights programs, projects, and activities that occurred during the year, as well as details of normal operations and brief statistics.https://digitalcommons.du.edu/libraries_reports/1001/thumbnail.jp

Patellar mechanics during simulated kneeling in the natural and implanted knee

AbstractKneeling is required during daily living for many patients after total knee replacement (TKR), yet many patients have reported that they cannot kneel due to pain, or avoid kneeling due to discomfort, which critically impacts quality of life and perceived success of the TKR procedure. The objective of this study was to evaluate the effect of component design on patellofemoral (PF) mechanics during a kneeling activity. A computational model to predict natural and implanted PF kinematics and bone strains after kneeling was developed and kinematics were validated with experimental cadaveric studies. PF joint kinematics and patellar bone strains were compared for implants with dome, medialized dome, and anatomic components. Due to the less conforming nature of the designs, change in sagittal plane tilt as a result of kneeling at 90° knee flexion was approximately twice as large for the medialized-dome and dome implants as the natural case or anatomic implant, which may result in additional stretching of the quadriceps. All implanted cases resulted in substantial increases in bone strains compared with the natural knee, but increased strains in different regions. The anatomic patella demonstrated increased strains inferiorly, while the dome and medialized dome showed increases centrally. An understanding of the effect of implant design on patellar mechanics during kneeling may ultimately provide guidance to component designs that reduces the likelihood of knee pain and patellar fracture during kneeling

An Automated Process for 2D and 3D Finite Element Overclosure and Gap Adjustment using Radial Basis Function Networks

In biomechanics, geometries representing complicated organic structures are consistently segmented from sparse volumetric data or morphed from template geometries resulting in initial overclosure between adjacent geometries. In FEA, these overclosures result in numerical instability and inaccuracy as part of contact analysis. Several techniques exist to fix overclosures, but most suffer from several drawbacks. This work introduces a novel automated algorithm in an iterative process to remove overclosure and create a desired minimum gap for 2D and 3D finite element models. The RBF Network algorithm was introduced by its four major steps to remove the initial overclosure. Additionally, the algorithm was validated using two test cases against conventional nodal adjustment. The first case compared the ability of each algorithm to remove differing levels of overclosure between two deformable muscles and the effects on mesh quality. The second case used a non-deformable femur and deformable distal femoral cartilage geometry with initial overclosure to test both algorithms and observe the effects on the resulting contact FEA. The RBF Network in the first case study was successfully able to remove all overclosures. In the second case, the nodal adjustment method failed to create a usable FEA model, while the RBF Network had no such issue. This work proposed an algorithm to remove initial overclosures prior to FEA that has improved performance over conventional nodal adjustment, especially in complicated situations and those involving 3D elements. The work can be included in existing FEA modeling workflows to improve FEA results in situations involving sparse volumetric segmentation and mesh morphing. This algorithm has been implemented in MATLAB, and the source code is publicly available to download at the following GitHub repository: https://github.com/thor-andreassen/femorsComment: 26 Pages, 5 Figures, 2 Table

Effect of Football Shoe Collar Type on Ankle Biomechanics and Dynamic Stability During Anterior and Lateral Single-Leg Jump Landings

In this study, we investigated the effects of football shoes with different collar heights on ankle biomechanics and dynamic postural stability. Fifteen healthy college football players performed anterior and lateral single-leg jump landings when wearing high collar, elastic collar, or low collar football shoes. The kinematics of lower limbs and ground reaction forces were collected by simultaneously using a stereo-photogrammetric system with markers (Vicon) and a force plate (Kistler). During the anterior single-leg jump landing, a high collar shoe resulted in a significantly smaller ankle dorsiflexion range of motion (ROM), compared to both elastic (p = 0.031, dz = 0.511) and low collar (p = 0.043, dz = 0.446) types, while also presenting lower total ankle sagittal ROM, compared to the low collar type (p = 0.023, dz = 0.756). Ankle joint stiffness was significantly greater for the high collar, compared to the elastic collar (p = 0.003, dz = 0.629) and low collar (p = 0.030, dz = 1.040). Medial-lateral stability was significantly improved with the high collar, compared to the low collar (p = 0.001, dz = 1.232). During the lateral single-leg jump landing, ankle inversion ROM (p = 0.028, dz = 0.615) and total ankle frontal ROM (p = 0.019, dz = 0.873) were significantly smaller for the high collar, compared to the elastic collar. The high collar also resulted in a significantly smaller total ankle sagittal ROM, compared to the low collar (p = 0.001, dz = 0.634). Therefore, the high collar shoe should be effective in decreasing the amount of ROM and increasing the dynamic stability, leading to high ankle joint stiffness due to differences in design and material characteristics of the collar types

2016 College of Health Science Sustainability Report

In publishing our sustainability report for the College of Health Sciences (COHS) at Boise State University, we are making our first attempt to transparently report on the social, economic, and environmental impacts that we have on our key stakeholders, and role model this leading corporate and organizational practice to inspire our business and academic peers to follow suit. With combined efforts and support from the College of Business and Economics (COBE), who will be publishing their third sustainability report this year, COHS was successful in developing our initial report. To fully align with our values, we put experiential learning at the heart of this effort: 14 student sustainability reporters, ranging from graduate and undergraduate levels from COHS and COBE researched, collected data, and wrote this report, and 30 students from the Beta Alpha Psi Honors Society and the graduate accounting class 505: Perspectives in Auditing conducted the report’s review. Organizing Frameworks To create this report, we leveraged the leading sustainability reporting frameworks from the corporate and business school realms respectively, namely the Global Reporting Initiative (G4), the UN Principles for Responsible Management Education (UNPRME), and the Association for the Advancement of Sustainability in Higher Education (AASHE) STARS guidelines. For the COHS report, leveraging of frameworks began early by two Masters of Health Science Capstone students Stephanie Pustejovsky and Jordan Harris. Building the foundation for our report was these bright students senior capstone project. Responsibilities included researching and analyzing sustainability frameworks, reviewing the COBE report, and deliberating on personal experiences at COHS to create materials to begin the development of a sustainability report that reflects the current state and future goals of the College. Top Areas of Excellence • Through Integrated Service-Learning projects, the COHS students have provided 25,965 hours of service to the Boise community (details on pg. 34). • Generating close to $6 million in Gross Revenue through the creation of eight Self-Support programs (details on pg. 43). Top Areas of Improvement • Improve student retention and graduation rates (details on pg. 26)

Statistical Shape and Intensity Modeling of the Shoulder

Anatomical variability in the shoulder is inherently present and can influence healthy and pathologic biomechanics and ultimately clinical decision-making. Characterizing variation in bony morphology and material properties in the population can support treatment and specifically the design, via shape and sizing, of shoulder implants. Total Shoulder Arthroplasty (TSA) is the treatment of choice for glenohumeral osteoarthritis as well as bone fracture. Complications and poor outcomes in TSA are generally influenced by the inability of the implant to replicate the natural joint biomechanics and by the bone quality around the fixation features. For this reason, knowledge of bony morphology and mechanical properties can support optimal implant design and sizing, and thus improve TSA results. Statistical shape and intensity modeling is a powerful tool to represent the shape and mechanical properties variation in a training set. Accordingly, the objectives of this thesis were: 1) to develop a statistical shape model (SSM) of the proximal humeral cortical and cancellous bone; 2) to develop an SSM and a statistical intensity model (SIM) of the scapular bone. A training set of 85 humeri and 53 scapulae were reconstructed from CT scans and registered to common templates. Principal Component Analysis (PCA) was applied to the registered geometries to quantify morphological and bone properties variation in the population. For both the humerus and the scapula SSM, the first mode of variation accounted for most of the variation and described scaling. Subsequent modes described changes in the scapular plate, acromion process and scapular notch for the scapula, and in the neck angle, head inclination, greater and lesser tubercles for the humerus. Variation in cortical thickness of the humeral diaphysis was largely independent of size and statistically significant differences with ethnicity were noted. Asian subjects showed higher humeral cortical thickness with respect to Caucasians, regardless of gender. The first mode of variation in the scapular SIM described scaling in material properties distribution, with higher bone density located centrally and anteriorly in the glenoid region. The bone property maps developed for the scapular training set realistically captured inter-subject variability and they represent a valuable tool to assess fixation features and screw location and trajectories for TSA glenoid component. The SSMs and SIM developed in this thesis represent a useful infrastructure to support population-based evaluations and assess possible anatomical differences with gender and ethnicity, SSM and SIM can also provide anatomical relationship in support of implant design and sizing

Dislocation Mechanics of Total Hip Arthroplasty: A Combined Experimental and Computational Analysis

While total hip arthroplasty is considered a successful procedure, dislocation remains a serious complication as recurrent dislocations may require additional surgeries. Knowledge on dislocation events as they occur in vivo are limited, therefore researchers rely on experimental and computational methods. A custom MATLAB script and an experimental procedure utilizing a six-degree of freedom actuator were developed to further understand how various surgical considerations affect dislocation mechanics in total hip arthroplasty. Computationally, it was determined that impingement free range of motion is limited during internal rotation in flexion and during external rotation in extension. Experimentally, our results suggest that the posterior approach provides more stability to anterior dislocations as the soft tissue structures became taut sooner in the rotation. Additionally, we found that dual mobility total hip arthroplasty provided a greater resistive torque during an impingement event than conventional total hip arthroplasty

Design of the High-Speed Stereo Radiography System

Orthopaedic pathologies often involve disruption of the mechanical environment of a joint at/below the mm scale. The ability to measure biomechanical kinematics at the sub-mm scale is essential for obtaining valuable insight into pathologies, but small motions of the joints are difficult to quantify. Estimates of skeletal kinematics are commonly made from optical motion capture systems and markers placed on the skin. The error caused by external marker movement is largely avoided with x-ray motion capture. Dynamic radiography uses a series of x-ray images recorded at high-speed and captures in-vivo joint motion. Uncovering the mechanical foundation of orthopaedic pathologies requires accurate and high-speed kinematic measurement of in-vivo 3D, six DOF joint motion. To meet these aims, requirements were established to guide the design, construction, and validation of a high-speed stereo radiography (HSSR) system. The completed system is capable of imaging major joints from the ankle to the cervical spine

Biomechanical Evaluation of Glenohumeral Joint Stabilizing Muscles During Provocative Tests Designed to Diagnose Superior Labrum Anterior-Posterior Lesions

Despite considerable advances in the understanding of glenohumeral (GH) biomechanics and glenoid labral pathologies, arthroscopy remains the only definitive means of Superior Labrum Anterior-Posterior (SLAP) lesion diagnosis. Unfortunately, natural GH anatomic variants limit the reliability of radiography. Accurate clinical diagnostic techniques would be advantageous due to the invasiveness, patient risk, and financial cost associated with arthroscopy. Twenty provocative tests designed to elicit labral symptoms as a diagnostic sign have shown promising accuracy by their respective original authors, but later studies generally fail to reproduce those findings. The purpose of this study was to compare the behavior of GH joint stabilizing muscles in promising tests. Electromyography (EMG) was used to characterize the activation of GH joint stabilizing muscles, with particular interest in the Long Head Biceps Brachii (LHBB) behavior, as activation of the LHBB and subsequent tension in the biceps tendon should illicit labral symptoms in SLAP lesion patients. Volunteers (n=21) with no history of shoulder pathology were recruited for this study. The tests analyzed were Active Compression, Speed’s, Pronated Load, Biceps Load I (Bicep I), Biceps Load II (Bicep II), Resisted Supination External Rotation (RSER), and Yergason’s. Test modifications that allowed the use of the Biodex System improved reproducibility. EMG was used to record activity for GH muscles: the LHBB, short head of the biceps brachii, anterior deltoid, pectoralis major, latissimus dorsi, infraspinatus, and supraspinatus. An indwelling electrode was used to monitor supraspinatus activity, and the remaining muscles utilized surface electrodes. EMG data were recorded at 1250 Hz and filtered with custom MATLAB software. Muscle activity for each test was characterized by activation and selectivity. Muscle activation was defined as the muscle’s peak normalized EMG amplitude. Muscle selectivity was defined as the ratio of muscle activation for the muscle of interest over the sum of all seven muscles’ peak activations. Results indicated that Bicep I and II had the greatest potential for the clinical detection of SLAP lesions because both tests 1) elicited large LHBB activation, suggesting that during these tests more tension was applied to the biceps tendon, and also 2) remained highly selective for the LHBB, which should reduce the potential sources for confounding results. Also, tests that elicited promising LHBB behavior for either a single suite or for both activation and selectivity, shared design patterns relating to location of the applied load, forearm orientation, joint position, and line of pull. These characteristics should be further examined to determine their potential role in optimizing SLAP test design and improving clinical diagnostic techniques

Revision Total Hip Femoral Stem Micromotion and Statistical Shape Modeling of the Knee

The first purpose of this thesis was to compare the amount of micromotion seen in the femoral stem in a revision total hip arthroplasty between simple loading conditions and loading conditions derived from activities of daily living, through the use of experimental and computational methods. The amount of micromotion at the bone-implant interface was larger for activities of daily living, with ranges of 200μm more than the largest simple loading conditions. The second purpose of this thesis was to compare measurements of accuracy in a statistical shape model between individual bone and joint-level models, specifically for the knee. Using computational methods, this study suggested that individual bone models produced lower amounts of errors in accuracy measurements than joint-level models, specifically when looking at similar number of modes of variation in each model. These two studies present research in the development of the next generation of implants in total joint arthroplasties