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Articular cartilage is a material with the appearance of simplicity and uniformity, but the chemical and biological structure of this material is very complex and not yet known in every detail. Our knowledge of cartilage wear behavior is limited and needs to be enlarged. Knowledge in this area could be important for the prevention and treatment of degenerative joint diseases. Within the framework of this thesis. a literature search focused on the key words joint lubrication and cartilage wear was conducted. The result of this search was that almost all studies and experiments which have been carried out to investigate tribilogical processes in synovial joints focused on friction behavior. Only a few tests dealing with cartilage wear were conducted. Most of the cartilage wear studies were carried out under exaggerated conditions which might change the wear mechanisms. Two studies were undertaken under conditions close to normal conditions occurring in natural joints; one in entire joints with a pendulum device, the other one with a cartilage-on-cartilage test system. The test devices used in these tests offered no or limited opportunities for the variation of the test parameters. Test parameters are, for example, the type of motion, applied load, velocity, variation of the velocity during each cycle, type of specimen, and test fluid composition. In consideration of the findings of the literature search, it was decided to design a new test device providing the capability of measuring friction, wear, and displacement due to wear and/or cartilage deformation. Furthermore, the new test device for cartilage wear studies, allows the variation of the above mentioned test parameters. / Master of Science

This study focuses on the design and implementation of a humanoid robot for disaster response. In particular, this thesis investigates the lower body design in detail with the upper body discussed at a higher level. The Tactical Hazardous Operations Robot (THOR) was designed to compete in the DARPA Robotics Challenge where it needs to complete tasks based on first-responder operations. These tasks, ranging from traversing rough terrain through driving a utility vehicle, suggest a versatile platform in a human sized form factor. A physical experiment of the proposed tasks generated a set of joint range of motions (RoM). Desired limb lengths were determined by comparing existing robots, the test subject in the experiment of proposed tasks, and an average human. Simulations using the desired RoM and limb lengths were used to calculate baseline joint torques. Based on the generated design constraints, THOR is a 34 degree of freedom humanoid that stands 1.78 [m] tall and weighs 65 [kg]. The 12 lower body joints are driven by series elastic linear actuators with multiple joints actuated in parallel. The parallel actuation mimics the human body, where multiple muscles pull on the same joint cooperatively. The legs retain high joint torques throughout their large RoM with some joints achieving torques as high as 289 [Nm]. The upper body uses traditional rotary actuators to drive the waist, arms, and head. The proprioceptive sensor selection was influenced by past experience on humanoid platforms, and perception sensors were selected to match the competition. / Master of Science

PURPOSE The purpose of this study was to determine if performing static active knee extension hamstring stretching using the Pneumex Pro-Vibe vibrating platform increased acute hamstring range of motion (ROM) greater than traditional static active knee extension hamstring stretching. METHODS: A within subject design was utilized with subjects undergoing static stretching with vibration and without vibration (conditions counterbalanced). Pre- and post-test active and passive ROM was measured for the right leg, with subjects first undergoing a 5-minute warm-up on a stationary bicycle. Supine active knee extension was performed on the Pro-Vibe platform with and without vibration. The stretch was held 3 times each for 30 seconds, with a 20-second rest period between each stretch. Vibration was set at 30 Hz at the “high” amplitude setting. Active hamstring ROM was measured via active knee extension using a goniometer with the leg in 90° of hip flexion. Passive ROM was measured via clinician-assisted knee extension with the leg in 90° of hip flexion. RESULTS: A 2-way repeated measures ANOVA was performed for passive ROM, and revealed a significant main effect for condition, F (1, 23) = 0.5875, p < 0.05, and time, F (1, 23) = 5.029, p < 0.05. Another repeated measures ANOVA was performed for active ROM with the same factors, and revealed a significant time by condition interaction, F (1, 23) = 4.730, p < 0.05, and a significant main effect for time, F (1, 23) = 18.612, p < 0.001. Post-hoc paired samples t-tests determined the difference between the pre-test and post-test measurements for each condition. Active ROM showed a significant difference pre-test to post-test for the vibration condition, t (23) = -5.41, p < 0.001. The vibration condition also resulted in significantly different pre-test vs. post-test measurements on passive ROM, t (23) = -2.55, p < 0.05. In both cases the average ROM was higher for the post-test. DISCUSSION: Three 30-second active knee extension hamstring stretches using a vibrating platform are sufficient to cause significant acute increases in hamstring ROM. These findings suggest this device may be useful when desiring increased hamstring ROM.

Im Rahmen der vorliegenden Arbeit wurden kapselumhüllte Hüftgelenkmodelle mit 22 – 44 mm Durchmesser durch Hebelwirkung luxiert, wobei die wirkende Kraft, die resultierende Dislokation und der intraartikuläre Absolutdruck kontinuierlich gemessen wurden. Parallel dazu wurde die technische Range of Motion bis zum Impingement und bis zur Luxation bestimmt. Die durchgeführten Hebelversuche ergaben bei Zunahme des Kopfdurchmessers eine erhebliche Zunahme des Luxationswiderstandes der untersuchten Gelenkmodelle. Im Gegensatz dazu ergab die Messung der technischen Range of Motion bei größerem Gelenkdurchmesser einen geringen Zuwachs, dessen praktische Wirksamkeit durch existierende Literatur auf Grund von Knochen-Knochen-Impingement in Zweifel gezogen wird (Burroughs et al. 2005). Die Hypothese ist somit anzunehmen. Die starke Zunahme des Luxationswiderstandes und die gering erweiterte techROM sprechen neben anderen Argumenten dafür, dass die permanente hüftstabilisierende Wirkung des atmosphärischen Druckes, die auch als Weber-Effekt bezeichnet werden kann, die Hauptursache für die deutlich verminderte Luxationsneigung größerer Köpfe nach hüftendoprothetischen Eingriffen darstellt. Daraus können folgende Konsequenzen für die Hüftendoprothetik abgeleitet werden: 1. Die Schonung und Rekonstruktion der Gelenkkapsel ist eine wichtige Voraussetzung für die Wirksamkeit des Weber-Effektes. Zahlreiche Studien belegen, dass durch die Kapselrekonstruktion die Anzahl der von Luxationen betroffenen Patienten um 90 % gesenkt werden kann (Pellicci et al. 1998; Bottner und Pellicci 2006; Prietzel et al. 2014), weshalb die Kapselrekonstruktion zu empfehlen ist. 2. Gelenkköpfe mit größerem Durchmesser besitzen in Folge des Weber-Effektes eine wesentlich größere Gelenkstabilität bzw. einen höheren Luxationswiderstand. Daraus resultiert offensichtlich die klinisch nachgewiesene wesentlich geringere Luxationsra-te (Bistolfi et al. 2011; Howie et al. 2012, Zajonz et al. 2015). Gegenwärtige Nachteile größerer Köpfe wie höherer Abrieb und vermehrte Belastung von Pfannenveranke-rung und Konus müssen jedoch berücksichtigt werden. Der Einsatz größerer Gelenk-köpfe ist zukünftig in der Hüftendoprothetik anzustreben. Gegenwärtig ist bei normalem Luxationsrisiko und somit bei primären HTEP-Implantationen der Einsatz von Gelenkköpfen bis 36 mm Durchmesser vertretbar. Bei erhöhtem Luxationsrisiko (z. B. bei bestimmten HTEP-Revisionen) sind dagegen 40-mm- und 44-mm-Köpfe gerechtfertigt, soweit diese in Abhängigkeit vom Pfannendurchmesser realisierbar sind (Zajonz et al. 2015). 3. Der Einsatz einer intrakapsulären Redondrainage beschleunigt durch die Eliminierung eingedrungener Luft und durch die Minimierung des postoperativen Hämatoseroms die Restitution physiologischer Gelenkverhältnisse. Dies ist gleichfalls eine wichtige Voraussetzung für die Wirksamkeit des Weber-Effektes und daher zu empfehlen (Prietzel et al. 2007).

[Truncated abstract] Measuring the kinematics of joints and implants following orthopaedic surgery is important since joint motion directly influences the functional outcome of the patient and the longevity of the implant. Radiostereometric Analysis (RSA) has been used to assess the motion over time of various joints and implant designs following corrective orthopaedic and joint replacement surgery for more than 20 years in more than 10,000 patients around the world. While the use of RSA reduces the risk of implanting potentially inferior prostheses on a large scale, conventional methodological procedures are based on the acquisition of static, stereographic x-ray images that are not suitable for measuring skeletal kinematics in a dynamic manner. The purpose of this thesis was to design, validate and test a novel technique for dynamically assessing the skeletal motion of human subjects using RSA and single-plane digital x-ray video fluoroscopy. The validation procedure utilised two in-vitro phantom models of human joints capable of simulating normal kinematic motion. These phantom models were supplied with realistic spatial displacement protocols derived from cadaveric specimens. The spatial positions of a series of tantalum markers that were implanted in each skeletal segment were measured using RSA. Skeletal motion was determined in x-ray fluoroscopy images by minimising the difference between the markers measured and projected in the single image plane. Accuracy was determined in terms of bias and precision by analysing the deviation between the applied displacement protocol and measured pose estimates. ... The RSA and low dose single-plane fluoroscopy technique developed, validated and tested in this thesis is capable of dynamically measuring the kinematics of any joint in the human body, following the implantation of small metallic markers in the surrounding bone during corrective orthopaedic surgery. The kinematics of joints with replacement prostheses, such as the total knee replacement (TKR), can be analysed in addition to the kinematics of joints without replacement prostheses, such as the sacroiliac joint. The technique may be used in the future on groups of human subjects enrolled in controlled trials that are designed to analyse the kinematics of the shoulder, spine, hip, knee, patella or ankle joints for the purposes of quantitatively comparing the kinematics of different prosthesis designs and various corrective orthopaedic procedures.

Today, movement measurements are made manually in healthcare using a goniometer. The measurements are often time-consuming and specially trained practitioners are needed, furthermore the readings are dependent on the practitioner's eye measurements. New technology has been introduced to make the same measurements using external sensors which have the disadvantage that they can be costly and space consuming. Recently, depth camera technology has introduced an alternative solution to make it more efficient for both patients and practitioners. The purpose of this study is to investigate whether Apple depth camera technology can replace current technology by being able to perform motion measurements with only one Ipad/Iphone with a built-in depth camera. For this, a prototype has been developed to be able to automatically calculate medically relevant angles by filming a person. Various motion measurements have been performed and the measurement results have been analysed. Apple depth camera has high precision in the measured values. However, a larger study needs to be performed in order to be able to determine whether Apple's depth camera could replace current technology. / Idag görs rörelsemätningar manuellt i vården med hjälp av en goniometer. Mätningarna är ofta tidskrävande och kräver utbildade utövare samt är beroende av utövarens ögonmått. Det har introducerats ny teknik för att göra samma mätningar med hjälp av externa sensorer, vilket har nackdelen att de kan vara kostsamma och utrymmeskrävande. På senare tid har djupkameratekniken introducerats som en alternativ lösning för att effektivisera för både patienter och vårdpersonal. Syftet med den här studien är att undersöka om Apples djupkamerateknik kan ersätta nuvarande teknik genom att kunna utföra rörelsemätningar med endast en Ipad/Iphone med inbyggd djupkamera. För detta har en prototyp utvecklats för att automatiskt kunna beräkna medicinskt relevanta vinklar genom att filma en person. Olika rörelsemätningar har sedan utförts och mätresultaten har analyserats. Resultaten av analysen visar att Apples djupkamera har hög precision i mätvärdena. Dock behöver en större undersökning utföras för att kunna konstatera om Apples djupkamera helt skulle kunna ersätta nuvarande teknik.

Idag görs rörelsemätningar manuellt i vården med hjälp av en goniometer. Mätningarna är ofta tidskrävande och kräver utbildade utövare samt är beroende av utövarens ögonmått. Det har introducerats ny teknik för att göra samma mätningar med hjälp av externa sensorer, vilket har nackdelen att de kan vara kostsamma och utrymmeskrävande. På senare tid har djupkameratekniken introducerats som en alternativ lösning för att effektivisera för både patienter och vårdpersonal. Syftet med den här studien är att undersöka om Apples djupkamerateknik kan ersätta nuvarande teknik genom att kunna utföra rörelsemätningar med endast en Ipad/Iphone med inbyggd djupkamera. För detta har en prototyp utvecklats för att automatiskt kunna beräkna medicinskt relevanta vinklar genom att filma en person. Olika rörelsemätningar har sedan utförts och mätresultaten har analyserats. Resultaten av analysen visar att Apples djupkamera har hög precision i mätvärdena. Dock behöver en större undersökning utföras för att kunna konstatera om Apples djupkamera helt skulle kunna ersätta nuvarande teknik. / Today, movement measurements are made manually in healthcare using a goniometer. The measurements are often time-consuming and specially trained practitioners are needed, furthermore the readings are dependent on the practitioner's eye measurements. New technology has been introduced to make the same measurements using external sensors which have the disadvantage that they can be costly and space consuming. Recently, depth camera technology has introduced an alternative solution to make it more efficient for both patients and practitioners. The purpose of this study is to investigate whether Apple depth camera technology can replace current technology by being able to perform motion measurements with only one Ipad/Iphone with a built-in depth camera. For this, a prototype has been developed to be able to automatically calculate medically relevant angles by filming a person. Various motion measurements have been performed and the measurement results have been analysed. Apple depth camera has high precision in the measured values. However, a larger study needs to be performed in order to be able to determine whether Apple's depth camera could replace current technology.

The purpose of the study was to quantify the relative contribution of low back flexibility and hamstring flexibility in the sit and reach test item of the AAHPERD Health Related Fitness Test in order to examine the validity of the sit and reach test. Subjects were 100 female students, 13 to 15 years of age in physical education classes. Hamstring flexibility was measured using the Leighton flexometer. Spinal mobility was measured using a tape measure. The sit and reach test was performed according to instructions given in the AAHPERD Test Manual. Data were analyzed using correlation, linear regression, and multiple regression. Conclusions of the investigation were (1) hamstring flexibility is moderately related to the sit and reach test, (2) low back flexibility has a very small relationship to the sit and reach test, and (3) the sit and reach test is an inadequate measure of low back and hamstring flexibility.