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It was demonstrated in recent studies that Complementary Limb Motion Estimation (CLME) is robust approach for controlling active knee prostheses. A wearable sensor system is then needed to provide inputs to the controller in a real-time platform. In the present work, a wearable sensor system based on magnetic and inertial measurement units (MIMU) together with a simple calibration procedure were proposed. This sensor system was intended to substitute and extend the capabilities of a previous device based on potentiometers and gyroscopes. The proposed sensor system and calibration were validated with an Optical Tracking System (OTS) in a standard gait lab and first results showed that the proposed solution had a performance comparable to similar studies in the literature.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The c2 goodness-of-fit (GOF) test was used to determine which standard femoral component would achieve the best geometrical fit for a specific patient. This was done by creating 3D models from computerized tomography scan data through computer segmentation using Materialise MIMICS. The second step was to measure the morphological dimensions of the distal femur whereof twelve were selected and compared to the dimensions of two commercial femoral prosthesis designs. Thirdly, cadaveric femurs were scanned with a 3D desktop scanner to create a database with the dimensions of healthy knees. The 3D model database of the cadaveric femurs included cartilage layer. A cartilage thickness was added to the CT knee dimensions using a self-organizing map (SOM) calculation based on the healthy knee database. The developed method calculated alignment angles with higher accuracy than presently used and determined preoperatively which size to implant. Kinematic simulations of total knee arthroplasty (TKA) knees were compared to normal knee simulations created in LifeMOD. The articulating surface was the only variable changed between the two simulations and the kinematics of different sizes were evaluated. A method was created to scale the femoral component using the standard available sizes. The completed project will be used as foundation for customization of TKA prostheses. / AFRIKAANSE OPSOMMING: Die c2 graad van passing toets metode was gebruik om te bereken watter standaard femorale komponent ’n patiënt die beste geometries pas. Dit was gedoen deur eerstens 3D modelle gemaak vanaf CT skandeer data deur rekenaar segmentasie met Materialise MIMICS. Daarna was morfologiese dimensies gemeet vanaf die distale femur, waarvan twaalf gekies en vergelyk was teen two kommersiële femorale prostesis ontwerpe. Laastens was kadawer femurs geskandeer met ‘n 3D skandeerder om ’n databasis van gesonde knieë te maak. Die 3D modelle van die kadawer bene het die kraakbeen laag bevat. Die kraakbeen dikte was by die CT knie dimensies gevoeg d.m.v. SOM en die gesonde knie databasis. Die nuwe metode bereken die belynings hoeke met hoër akkuraatheid as wat huidiglik gebruik word en bereken voor die operasie watter grote om te gebruik. Kinematiese simulasies van knie prostesis was vergelyk met ’n normale knie simulasies gemaak in LifeMOD. Die artikulêre oppervlakte was die enigste veranderlike tussen die twee simulasies en kinematika van verskillende grotes was ondersoek. ‘n Metode was geskep om die standaard femorale komponent se skaal te verander vir ’n beter passing.

Durch ansteigende Alterserwartung werden Behandlungen für Erkrankungen des Bewegungsapparats immer relevanter. Gerade das Knie wird über die Zeit hinweg stark belastet und ist auch durchgehend in Benutzung. Durch Fehlstellungen, Brüche oder auch Arthrose kann es zum kompletten Ver-schleiß dieses Gelenks kommen. Da in einigen Fällen die konservativen Behandlungsmethoden versagen, wird ein Ersatz des Kniegelenks in Erwägung gezogen. Dieser Ersatz wird heutzutage durch Standardprothesen schon gut abgedeckt. Die Bewegungsfähigkeit kann wiederhergestellt und Schmerzen können reduziert werden. Durch das weiterhin ansteigende Alter kommen immer mehr Revisionsendoprothesen zum Einsatz, da die Lebensdauer einer Knieendoprothese nur begrenzt ist. Um diese zu verlängern, kann man eine an den Bewegungsapparat individuell angepasste Prothese implantieren, die der Belastung besser gewachsen ist. Die Erstellung solcher individueller Prothesen ist Aufgabe des Forschungs- und Entwicklungsprojektes EXPERTEB (EXPERTEB 2018). Um solch eine angepasste Prothese herzustellen, benötigt dies jedoch konkrete Maße des Knies. Diese Arbeit soll ein Verfahren präsentieren, mit dem es möglich ist, anhand von CT-Aufnahmen des Kniegelenks alle nötigen geometrischen Maße zu bestimmen. Kern des Verfahrens ist ein angelerntes Statistical Shape Model (SSM), dass nur die nötigen und zu erwartenden Verformungen des Modells zulässt, sodass es sich an das im Datensatz dargestellte Knie anpassen kann. [... aus der Einleitung]

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.