Thesis (M.Sc. (Anatomy))--Mahidol University, 1979.

Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisor: Irene S. Davis, Dept. of Physical Therapy. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2005. / Includes bibliographical references (leaves 92-96). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (Ph. D.)--Oregon State University, 2005. / Includes bibliographical references (leaves 92-96).

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Michael E. Hahn. Includes bibliographical references (leaves 50-56).

Introduction: Une procédure fréquente pour la prévention de l’arthrose de la cheville est une ostéotomie corrective du tibia distal (SMOT). Le Distal Tibia Nail (DTN ; Mizuho®), a été développé pour la réduction des fractures du tibia distal. L’objectif de ce projet était d’analyser la faisabilité du DTN pour des procédures SMOT effectuées avec une ouverture médiale (MWO). Méthodes : Au total 16 Sawbones® ont été instrumentés par un DTN ou une plaque (MDTP, Synthes®), suivi par la simulation d’une MWO. Quatre phases d’expérimentation étaient définies : Phase-0, Sawbones sans implant ni MWO ; Phase-1, échantillons avec un implant et MWO. Phase-2, les échantillons de la Phase-1 avec le cortex latéral fracturé ; Phase-3, simulation d’une fracture de type A3. La raideur et le mouvement inter-fragmentaire (IFM) étaient analysés. Des tomographies des échantillons ont été prises à Phases 0 et 1. Résultats : Jusqu’à 80% de différence était présente enter les Sawbones® de Phase-0 ; dans les Phases 1 et 2, des différences importantes se sont montrées entre des implants mais équivalent à <2 mm d’IFM. Le DTN a démontré une résistance très élevée aux charges appliquées en comparaison avec le MDTP pour la fixation des fractures A3. Des facteurs expérimentaux tels que la raideur initiale des Sawbones®, l’axe de chargement, et le positionnement de l’échantillon dans la machine d’essai, peuvent tous avoir une influence importante sur la raideur mesurée. Conclusion : Le DTN peut être considéré comme option pour la fixation des SMOT effectués avec un MWO. Des études futures doivent faire attention aux conditions limites ayant un effet sur des critères d’évaluation et des conclusions tirées / Introduction: Supra-malleolar corrective osteotomies (SMOT) are a common surgical procedure for the prevention of early onset of ankle arthritis. The Distal Tibia Nail (DTN; Mizuho®), was previously developed for the reduction of distal tibia fractures. The aim of this project was to identify error sources in biomechanical testing, and to test the feasibility of the DTN for SMOT performed using the medial wedge opening (MWO) technique. Methods: A total of 16 Sawbones® were each implanted with either a DTN or medial distal tibia plate (MDTP; Synthes®), and a MWO simulated. Four testing phases were defined: Phase-0, testing of Sawbones® without implant/osteotomy; Phase-1, samples with MWO and implant; Phase-2, Phase-1 samples with lateral cortex fractured; Phase-3, samples with an A3 type fracture. Stiffness construct and interfragmentary movement (IFM) were analysed. CT scans were taken of the samples at Phases 0 and 1. Results: Up to 80% difference was noticed between Sawbones® samples in Phase-0; in Phases 1 and 2 significant differences were found between stiffness constructs of the implant groups but this amounted to <2 mm IFM. The DTN was significantly more resistant to compression and torsion when supporting an A3 fractures (Phase-3). Elements such as original Sawbones® stiffness construct, implant position, potting material, loading axis, and sample positioning can have a high influence on measured stiffness and bias the results. Conclusion: The DTN is a viable option for the fixation of SMOT performed with a MWO technique. Future studies should pay careful attention to boundary conditions affecting outcomes measures and drawn conclusions

Las fracturas diafisiarias de tibia, son de las lesiones mas frecuentes en traumatología, siendo una de sus principales causas los accidentes de transito: choques, atropellos; violencia física caídas, accidentes deportivos entre otras causas. Se revisaron todas las Historias Clínicas de pacientes que ingresaron al Hospital Sergio E. Bernales con el Diagnostico de fracturas diafisiarias de tibia, un total de 76 Historias Clínicas, de las cuales 42 fueron seleccionadas para el presente trabajo por tener los criterios de inclusión, información completa y que fueron sometidos a intervención quirúrgica con el Sistema de Fijación Externa Descartable. La fijación externa es una opción mas, entre tantas otras posibilidades quirúrgicas, es ampliamente aceptada para fracturas expuestas como la primera opción, sin embargo para fracturas cerradas la bibliografía menciona otras posibilidades quirúrgicas como son el Clavo Intramedular, placas y tornillos según sea el caso. En el presente estudio, de 42 pacientes, 36 fueron hombres (85.71%), el promedio de edad de 20 – 29 años con 15 pacientes con un 35.71 % , el mecanismo de acción (atropello) 26 pacientes (61.9%), la tibia derecha se afecto en 27 pacientes (64.28%), fracturas cerradas 24 pacientes (57.14%), las fracturas tipo II de Aybar 15 pacientes (35.71%)fueron las mas frecuentes, se realizaron fasciotomia en 11 pacientes (26.19%), osteosintesis mínima en 15 pacientes (35.51%), el tiempo de consolidación vario de 6 – 15 meses, las tipo I de Aybar consolido en 8.57 meses. / Tesis de segunda especialidad

This thesis is missing pages 98-107, all of which are not in the other copies of the thesis. -Digitization Centre / In total knee arthroplasty with bone defect of the tibia, it was believed that with older designs of tibial tray, both block and stem augments must be used with the tibial tray to improve the knee stability. Obviously, the extended stem causes more difficulties to the surgery as well as more suffering to the patients. Getting rid of the extended stem and still maintaining enough stability is therefore very desirable. The newest tray design, Deltafit Keel tray, which provides much more contact with the human bone structure, may provide enough stability without the extra long stem. The objective in this project is to answer the questions - Is the stem augmentation definitely required alongside the block implant for the cases of bone defect in TKA (Total Knee Arthroplasty) when using the Deltafit Keel tibial tray design? In other words, does the configuration of Deltafit Keel tray with a block provide enough stability in the cases of bone defect? In order to give a reliable answer, three configurations have been studied by conducting both experiments and FEA simulation. The three cases are Deltafit Keel tibial tray only (case 1-no bone defect defect), tray with block augment (case 2-with bone defect assumed) and tray with block and extended stem (case 3-with bone defect assumed). In this study, three commercially available composite bones with isotropic material properties are utilized. For each configuration, the bones are clamped in a testing apparatus and 3000 N static compressive load is imposed on the top surface of the tibia tray at central, medial and lateral locations. In experiment, the strains and displacements at strategically selected locations were measured by strain rosettes (strain gages) and DVRT (Differential Variable Reluctance Transducer) displacement transducers, respectively. In order to simulate the three cases, FE model is established by employing several advanced software including CATIA, True Grid Mesh generator and Abaqus. In order to compare with the experimental results, nine cases (three implant configurations with three different loading positions for each) have been simulated using Abaqus/Standard 6.4. In addition to the nine-case studies, the influence of load offsetting is also investigated by shifting the nodal load along medial-lateral and anterior-posterior directions. It is found that load shifting one node in either direction does not cause significant change in either strain or displacement. Furthermore, FE results of adjacent elements are checked as well and no sudden changes are observed. Since the discrepancy of the output from adjacent elements is negligible, an average value of the elements can be used to represent the output in a small region to compare the experimental strain measured by strain rosettes. Both the experimental data and FEA simulation results lead to the conclusion that comparable stability can be achieved with the configuration of Deltafit Keel tibial tray and a block as compared to the case of Deltafit Keel tray only without bone defect. Moderate improvement of stability, but with significant stress shielding, is found when the extended stem is implanted. For the amount of bone defect and the bone material properties used in this study, the Deltafit Keel tray with a block is the best choice because it is able to provide adequate stability and avoid excessive stress shielding. The loss of a substantial amount of bone to implant an extended stem to trade for the excessive stability may not be worthwhile. Besides, stress shielding is a potential problem which may exist if the extended stem is used. / Thesis / Master of Applied Science (MASc)

The mechanical response tissue analyzer (MRTA) tests long bone quality through low frequency, low amplitude vibration in vivo. The MRTA measures complex stiffness over a range of low frequencies, offering a wealth of information on bone composition. Previous MRTA interpretation used lumped parameter algorithms focused on reliably estimating the bone's bending stiffness (EI). To interpret the stiffness response, the first finite element (FE) simulation of the MRTA test of a human tibia was developed to identify dominant parameters that will possibly make linear prediction algorithms more suitable for estimating bone quality. Five FE models were developed in stages by adding complexity. Starting with a solid mesh of the diaphysis, each model was created from its predecessor by sequentially adding: a medullary canal, linear elastic (LE) cancellous epiphyses, linear viscoelastic (LVE) cancellous and cortical bone, and a LVE skin layer. The models were simulated in vibration using a direct steady-state dynamics procedure in ABAQUS to calculate the complex stiffness response. Natural frequency analysis (ABAQUS) verified that the FE models accurately reproduced previous experimental and computational resonances for human tibiae. A solid, LE cortex roughly matched the dominant frequency from experimental MRTA raw data. Adding the medullary canal and LVE properties to bone did not greatly spread the peak or shift the resonant frequency. Adding the skin layer broadened the peak response to better match the MRTA experimental response. These results demonstrate a simulation of the MRTA response based upon published geometries and material data that captures the essence of the instrument. / Master of Science

During landing, the human body is required to absorb impact forces throughout its tissues. Muscle and connective tissue is able to dissipate much of this force, however, a portion of the impact is delivered to the bones. Forces acting on the human skeleton can cause microscopic fractures which may lead to stress fracture. The present study seeks to calculate changes in the magnitude of strain using noninvasive methods. A musculoskeletal model representing a healthy male subject (22 years, 78.6 kg, 1.85 m) was created. A flexible tibia, created from a computed tomography scan of the subject’s right tibia, was included in the model. Motion capture data were collected while the subject performed drop landings from three separate heights (26, 39, and 52 cm) and used to compute simulations in LifeMOD. Surface electromyography and joint angle data were compared to their simulated counterparts using a cross correlation. Maximum magnitudes of principal and maximum shear strain were computed. The model had reasonable agreement between joint angle curves. A large Cohen’s d effect size showed that our subject had increased tibial strain and strain rate as the drop height increased. This study demonstrates a valid method of simulating tibial strain during landing movements. Future studies should focus on recruiting a larger sample and applying this method. / School of Physical Education, Sport, and Exercise Science