The major objective of this thesis was to investigate how the use of a recently developed microprocessor-controlled limb system altered the negative mechanical work done by the intact and prosthetic limb when trans-femoral amputees terminated gait. Participants terminated gait on a level surface from their self-selected walking speed and on declined surface from slow and customary speeds, using limb system prosthesis with microprocessor active or inactive. Limb negative work, determined as the integral of the negative mechanical (external) limb power during the braking phase, was compared across surface, speed and microprocessor conditions. Halting gait was achieved predominantly from negative work done by the trailing/intact. Trailing versus leading limb mechanical work imbalance was similar to how able body individuals halted gait. Importantly, the negative limb work performed on the prosthetic side when terminating gait on declined surface was increased when the microprocessor was active for both slow and customary speeds (no difference on level surface) but no change on intact limb. This indicates the limb system’s ‘ramp-descent mode’ effectively/dynamically altered the hydraulic resistances at the respective joints with evidence indicating changes at the ankle were the key factor for increasing the prosthetic limb negative work contribution. Findings suggest that trans-femoral amputees became more assured using their prosthetic limb to arrest body centre of mass velocity when the limb system’s microprocessor was active. More generally findings suggest, trans-femoral amputees should obtain clinically significant biomechanical benefits from using a limb system prosthesis for locomotion involving adapting to their everyday walking where adaptations to an endlessly changing environment are required. / Higher Committee of Education Development in IRAQ (HCED)

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

No description available.

Although dynamic prosthetic alignment is an important process for the rehabilitation of transtibial amputees, such alignment technique is subjective and inconsistent. Using biomechanical variables and questionnaire assessments, this study compared an instrument-assisted dynamic alignment technique using the Compas™ system and conventional alignment techniques on nine adults with unilateral transtibial amputation. A focus group discussion was conducted with six prosthetists to understand clinical practice of dynamic alignment and their perception of the Compas™ system. Results found that Compas™ produced more anterior weight line displacement and greater varus moment on the prosthesis than conventional alignment techniques. Alignment changes did not affect pelvic acceleration, and the instrument-assisted alignment technique produced certain biomechanical changes but not necessarily better alignments. Although the current version of the Compas™ system is not clinically feasible, it can be used as a teaching/justification tool. Further investigation with larger sample size and ankle alignment or moment measures is needed.

Although dynamic prosthetic alignment is an important process for the rehabilitation of transtibial amputees, such alignment technique is subjective and inconsistent. Using biomechanical variables and questionnaire assessments, this study compared an instrument-assisted dynamic alignment technique using the Compas™ system and conventional alignment techniques on nine adults with unilateral transtibial amputation. A focus group discussion was conducted with six prosthetists to understand clinical practice of dynamic alignment and their perception of the Compas™ system. Results found that Compas™ produced more anterior weight line displacement and greater varus moment on the prosthesis than conventional alignment techniques. Alignment changes did not affect pelvic acceleration, and the instrument-assisted alignment technique produced certain biomechanical changes but not necessarily better alignments. Although the current version of the Compas™ system is not clinically feasible, it can be used as a teaching/justification tool. Further investigation with larger sample size and ankle alignment or moment measures is needed.

In Germany alone, 10,000 to 12,000 transfemoral amputations occur every year. Persistent rehabilitation efforts and advanced medical devices like prosthetic knee joints are crucial to reintegrating amputees into daily life successfully. Modern knee joints represent a highly integrated mechatronic system including special kinematics, a lightweight design, various sensors, microprocessors and complex algorithms to control a damping system in the context of the given situation. A knee joint is a passive system and normally has no actuator for an active movement. To enable a natural gait pattern, dampers decelerate the swinging speed of the prosthesis depending on the walking speed and situation. The invention of a novel knee joint called VarioKnie provides two kinematics - a monocentric and a polycentric one. Both kinematics have diametrical advantages and the user can choose the preferred setting through an electromechanical switching unit. With this knee joint in mind, a special hydraulic damper is developed to support both kinematics. Requirements and technical data are provided in the present paper. State of art are microprocessor-controlled knee joints with only one kinematic and either a hydraulic, a pneumatic, or a rheological damper.