Bibliographic identification DINDA, Ondřej. Kinematic analysis of patients wiht femoroacetabular impingement syndrome. Prague: Charles University, 2nd Faculty of medicine, Department of Rehabilitation and Sports Medicine, 2017. 82 pages. Supervisor: Mgr. Petra Valouchová, Ph.D. Abstract The purpose of this master thesis was to find out, if there are objective changes in biomechanics of the gait and upstairs gait by objectives with diagnosed femoroacetabular impingement syndrome and by healthy objectives. The data were acquired using kinematic analysis Qualisys and processed using software Qualisys track manager and Visual3D. The subject of research was the range of motion in hip joint in frontal and sagittal plane, than the movement of pelvis in frontal plane, movement of pelvis against thorax in transversal plane and deviation of the axis of spine in frontal plane. These parameters were documented using angular deviation of the segments, deviation of the segments in the plane or shifting of the markers in coordinate system. The conclusions were than statistically evaluated. There were 20 objects with diagnosed femoroacetabular impingement syndrome in the age from 23 to 47 years of age included in the study. In the gait research, a significant difference in angular deviation of the pelvis against thorax in...

Das Ziel der Arbeit war eine quantitative Analyse des Subakromial- und Subkorakoidalraums anhand von berechneten Minimaldistanzen an 3D-Schulter-Modellen in verschiedenen Abduktionspositionen sowie in klinisch relevanten Impingement-Test-Positionen. Von 14 Patienten mit einseitigem Impingement-Syndrom der Schulter und 14 schultergesunden Probanden wurden im offenen MRT-System Aufnahmen beider Schultern in 0°, 45°, 90° und 135° Abduktion und den Impingement-Positionen nach Neer und Hawkins angefertigt. An der kranken Schulter wurden sowohl prä- als auch postoperative Serien aufgenommen. Bei der MRT-Bilddatenbearbeitung erfolgte eine manuelle Segmentierung der MR-Bilddaten, die Bildung eines 3D-Oberflächenmodells der knöchernen Strukturen der Schulter und anschließend die Berechnung verschiedener Minimaldistanzen (akromiohumeral, klavikulohumeral, korakohumeral, korakotuberkulär). Die symptomatische Schulter der Patienten zeigte keine signifikant unterschiedliche Akromiohumeraldistanz unter Abduktion im Vergleich zur gesunden Seite. Gegenüber der schultergesunden Gruppe ergab sich eine signifikante Reduktion des akromiohumeralen Intervalls in 90° und 135°. Das subkorakoidale Intervall stellte sich an der Impingement-Schulter sowohl unter Abduktion als auch in den Impingement-Manövern signifikant kleiner als bei den Probanden dar. Die kranke Schulter war in Neer-Einstellung durch eine signifikant kleinere Akromiohumeraldistanz gegenüber der asymptomatischen Schulter sowie den Probanden charakterisiert. Die Hawkins-Position wies dagegen signifikant verminderte subkorakoidale Distanzen an der kranken Schulter auf. Die Akromiohumeraldistanz an der gesunden Schulter der Patienten war nur in 135°-Position signifikant kleiner im Vergleich zu den Probanden. Die korakotuberkuläre Strecke war ähnlich der kranken Schulter auch auf der asymptomatischen Patientenschulter in allen Abduktionspositionen signifikant kleiner als an der Probandenschulter. Postoperativ präsentierte sich der Akromiohumeralraum bei Abduktion bis 90° signifikant erweitert zum präoperativen Befund. Im Vergleich zur gesunden Schulter und den Probanden war die Erweiterung nur noch in 45° und 90° signifikant. Die Klavikulohumeraldistanz zeigte zwischen den einzelnen Gruppen kaum signifikante Unterschiede. Es lässt sich schlussfolgern, dass ein einseitiges Impingement-Syndrom der Schulter nicht mit einer signifikanten Reduktion der Akromiohumeraldistanz unter Abduktion im Vergleich zur gesunden Gegenseite einhergeht. Verglichen mit einem gesunden Normalkollektiv imponiert das Impingement-Syndrom mit einer signifikanten Reduktion der Akromiohumeraldistanz in den hohen Abduktionsgraden. Die arthroskopische subakromiale Dekompression als Therapieoption beim subakromialen Impingement-Syndrom erzeugt subakromiale Verhältnisse, die unter Abduktion bis 90° signifikant erweitert gegenüber dem präoperativen Bild und gesunden Schultern sind. Der klavikulohumerale Raum scheint nur geringen Einfluss auf die Pathogenese eines Impingement-Syndroms zu besitzen und sollte deshalb nicht als morphologischer Parameter in der Bilddiagnostik herangezogen werden. Es konnte außerdem herausgefunden werden, dass das morphologische Korrelat eines positiven Impingement-Tests nach Neer eine signifikant verminderte Akromiohumeraldistanz gegenüber gesunden Schultern darstellt. Ein positives Hawkins-Manöver geht mit einer signifikant reduzierten Korakohumeral- und Korakotuberkulärdistanz einher. Abschliessend kann festgestellt werden, dass mit der vorgestellten Methode eine Quantifizierung der Subakromialraumweite bei Probanden und bei Patienten mit subakromialem Impingement-Syndrom der Schulter in klinisch relevanten Gelenkpositionen durchgeführt werden kann. Auf Grund des erheblichen Zeitaufwandes der 3D-Bilddatenanalyse wird die Methode voraussichtlich ausschließlich wissenschaftlichen Fragestellungen vorbehalten bleiben.

Femoroacetabular impingement syndrome (FAI) is a hip impairment, which is according to recent studies significant contributor to hip osteoarthritis. Current research is dedicated to evaluate movement patterns of hip, pelvis and spine in patients with FAI using a motion analysis capture system. Biomechanics and kinesiology relations between spino-pelvic complex and lower limb joints led us to choose the topic of this thesis. The goal of this study was to define the movements of ankle and foot in patients with FAI syndrome and to compare with asymptomatic control group. To measure the parameters during gait we used Qualisys motion capture system and then the data were processed in Qualisys Track Manager 2020.03. We assessed the movements of ankle, rearfoot and the progression foot angle during the stance phase of gait cycle. Moreover, we measured the step length, gait speed and passive range of motion of the hip in both exploratory groups. In total we examinated 30 subjects, 15 with FAI syndrome and 15 asymptomatic volunteers with physiologic hip condition. We demonstrated three significant between group changes in average ankle range of motion in sagittal plane, foot progression angle and passive range of motion of the hip.

Femoroacetabular impingement (FAI) is recognized as a pathomechanical process that leads to hip osteoarthritis (OA). It is hypothesized that mechanical stimuli are prominent at higher range of motions in hips with cam FAI (aspherical femoral head-neck deformity). Adverse loading conditions can impose elevated mechanical stimuli levels at the articulating surfaces and underlying subchondral bone, which plays a predominant mechanical role in early OA. The aim of this research was to determine the levels of mechanical stimuli within the hip, examining the effects of severe cam impingement on the onset of OA, using patient-specific biomechanics data, CT data, and finite element analysis (FEA). Patient-specific hip joint reaction forces were applied to two symptomatic patient models and two control-matched models, segmented from patient-specific CT data. The finite element models were simulated to compare the locations and magnitudes of mechanical stimuli during two quasi-static positions from standing to squatting. Maximum-shear stress (MSS) was analyzed to determine the adverse loading conditions within the joint and strain energy density (SED) was determined to examine its effect on the initiation of bone remodelling. The results revealed that peak mechanical stimuli concentrations were found on the antero-superior acetabulum during the squatting position, underlying to the cartilage. The MSS magnitudes were significantly higher and concentrated for the FAI patients (15.145 ± 1.715 MPa) in comparison with the MSS magnitudes for the control subjects (4.445 ± 0.085 MPa). The FAI group demonstrated a slight increase in peak SED values on the acetabulum from standing (1.005 ± 0.076 kPa) to squatting (1.018 ± 0.082 kPa). Insignificant changes in SED values were noticed for the control subjects. Squatting orients the femoral head into the antero-superior acetabulum, increasing the contact area with the cartilage and labral regions, thus resulting in higher peaks behind the cartilage on the acetabulum. The resultant location of the peak MSS and SED concentrations correspond well with the region of initial cartilage degradation and early OA observed during open surgical dislocation. Due to the relatively low elastic modulus of the articular cartilage, loads are transferred and amplified to the subchondral bone. This further suggests that elevated stimuli levels can provoke stiffening of the underlying subchondral plate, through bone remodelling, and consequently accelerating the onset of cartilage degradation. Since mechanical stimuli results are unique to their patient-specific loading parameters and conditions, it would be difficult to determine a patient-specific threshold to provoke bone remodeling at this stage.

Excessive water flow velocities can contribute to rapid failures of copper premise plumbing systems. This is the first fundamental study to scientifically isolate mechanistic impacts from distinct flow induced failure mechanisms that include concentration cell corrosion, cavitation, particle/bubble impingement and high velocity impingement. Concentration cell effects resulting from exposing different copper surfaces to different flow regimes created a strong electrochemical cell that caused rapid corrosion that persisted for periods lasting from hours to days in certain waters. Free chlorine appeared to inhibit this effect in a range of waters. Under typical water chemistries the resulting non-uniform attack diminished, presumably due to formation of a protective scale or rust layer. Consequently, concentration cell corrosion would not be a major contributor to damage from high flow rates in the range of fresh waters investigated. In experiments using an ultrasonic processor, implosion of vaporous cavitation bubbles against a copper surface caused dramatic pitting, considerable copper weight loss, and, in some cases, the development of pinhole leaks. Changes in water chemistry and the existence of a pre-existing protective scale layer had nearly no mitigating effects on copper cavitation damage. An exponential relationship was found between the initial copper pipe wall thickness and the time necessary to cause a leak via vaporous cavitation. On the basis of this relationship, a Type M tube would be expected to last 23 and 3000 times less than a Type K and L tube, respectively, when facing continual cavitation attack. However, it was not possible to re-create cavitation damage in any practical circumstance that was tested in copper pipes, even though it is strongly believed that cavitation can play a practical role in service failures. On the basis of the above results, it was hypothesized that brief intervals of cavitation could remove protective scale from portions of the copper pipe surface exposed to high turbulence. In this case, even if minimal damage from cavitation occurred directly, it could allow concentration cell corrosion to become a significant contributor to non-uniform corrosion damage. On the basis of preliminary testing, it appears that this idea has considerable merit. A combination of brief cavitation and waters that create strong concentration cell effects is expected to cause serious damage to copper pipe. These potential synergies are deserving of additional research. In experiments testing the effect of high velocity jets (17.5 ft/sec) impinging against submerged copper plates perpendicularly and longitudinally, plates in heated sea water were aggressively gouged and penetrated. It is believed that the copper plate damage resulted from a combination of mechanisms including concentration cell corrosion, cavitation implosion, and high velocity impingement. Impingement of sand on the surface of copper tube created very little damage. This was surprising given prior reports in the literature. / Master of Science

The present work studies the relationship between target and sidewall surfaces of a multirow, narrow impingement channel at various jet heights with one impingement hole per row. Temperature sensitive paint and constant flux heaters are used to gather heat transfer data on the target and side walls. Jet-to-target distance is set to 1, 2, 3, 5, 7 and 9 jet diameters. The channel width is 4 jet diameters and the jet stream wise spacing is 5 jet diameters. All cases were run at Reynolds numbers ranging from 5,000 to 30,000. Pressure data is also gathered and used to calculate the channel mass flux profiles, used to better understand the flow characteristics of the impingement channel. While target plate heat transfer profiles have been thoroughly studied in the literature, side wall data has only recently begun to be studied. The present work shows the significant impact the side walls provide to the overall heat transfer capabilities of the impingement channel. It was shown that the side walls provide a significant amount of heat transfer to the channel. A channel height of three diameters was found to be the optimum height in order to achieve the largest heat transfer rates out of all channels.

This study focuses on multi-jet impingement for gas turbine geometries in which the objective is to understand the influence of the roughness elements on a target surface to the heat transfer. Current work has proven that implementing roughness elements for multi-jet impingement target surfaces has increased heat transfer ranging anywhere from 10-30%. This study has chosen to investigate three different roughness elements, elliptical in cross-section, to compare to smooth surface geometries for multi-jet impingement. An experimental was taken for this study to extend the current knowledge of multi-jet impingement geometries and to further understand the heat transfer performance. A temperature sensitive paint (TSP) technique was used to measure the heat transfer on the target surface, in which the local temperature was measured to estimate area averaged heat transfer coefficient (HTC) and row averaged HTC. In order stay consistent with literature, non-dimensional parameters were used for geometry locations and boundaries. For this study, the Reynolds number range, based on jet diameter and mass flux, is 10-15k. The X/D (streamwise direction), Y/D (spanwise direction), Z/D (channel height direction), L/D (thickness of the jet plate) constraints for this study are 5, 6, 3, and 1 respectively. From the local heat transfer distributions of the different roughness elements, it is concluded that the inclusion of these elements increases heat transfer by 2-12% as compared to a flat/smooth target plate. It is therefore recommended from this study, that elements, elliptical in shape, provide favorability in heat transfer for gas turbine configurations.

Introdução: As alterações anatômicas do fêmur proximal ou do acetábulo, como as decorrentes das sequelas da epifisiólise do fêmur proximal, da displasia do quadril da doença de Legg-Perthes-Calvé, podem levar ao desenvolvimento da artrose do quadril. No entanto, em torno de 80% dos indivíduos que desenvolvem essa doença têm uma anatomia óssea considerada normal. Ainda assim, surgiu a hipótese que alterações sutis do fêmur proximal ou do acetábulo, denominadas, respectivamente, cam e pincer, poderiam gerar um contato anormal entre essas estruturas ósseas, desencadear lesão condral e, como consequência, a artrose do quadril. Esse mecanismo foi denominado impacto fêmoro-acetabular. No entanto, a comprovação da relação entre o impacto e a artrose do quadril depende da uniformização dos critérios diagnósticos do cam e do pincer, ainda escassa e variável na literatura. Dessa forma, será possível a definição da prevalência e história natura do impacto fêmoro-acetabular e da sua relação com a artrose do quadril. Objetivo: Avaliar a prevalência do impacto fêmoro-acetabular tipo cam e tipo pincer em uma amostra de indivíduos assintomáticos. Pacientes e Métodos: Foram estudados 106 indivíduos assintomáticos (65 homens e 41 mulheres), com idade entre 20 e 40 anos. A condição determinante para a inclusão no estudo foi à ausência de história de dor no quadril ao longo da vida. Foram obtidas radiografias em ântero-posterior e Dünn 45°. A presença de cam foi determinada por um ângulo alfa, arbitrado, de 55° e a presença de pincer, quando observado o sinal da parede posterior e/ou o sinal de crossover. Resultados: Foi observada prevalência de cam de 29%; o sinal do crossover e da parede posterior ocorreram, respectivamente, em 20% e 29% dos indivíduos estudados. Pelo menos uma das imagens de impacto fêmoro-acetabular estava presente em 65% dos indivíduos da amostra. Conclusão: A prevalência encontrada das imagens de impacto fêmoro-acetabular (65%) está acima daquelas relatadas na literatura. É necessária a ampliação do estudo para confirmar os resultados encontrados e a realização de estudos prospectivos bem controlados para avaliar o papel do cam e do pincer no desenvolvimento da artrose do quadril. / Background: Anatomical abnormalities of the proximal femur or the acetabulum, such as those resulting from the consequences of slipped epiphyses of the proximal femur, the hip dysplasia of Legg-Calve-Perthes disease, could lead to the development of hip osteoarthrosis. Nevertheless, around 80% of individuals who develop this condition have a bone anatomy considered normal. Still, the hypothesis arose that subtle alterations of the proximal femur or the acetabulum, called, respectively, cam and pincer, could generate an abnormal contact between these bony structures, triggering chondral lesion and as a consequence, arthritis of the hip. This mechanism has been named femoroacetabular impingement. Nevertheless, evidence of the relationship between the impact and osteoarthritis of the hip depends on the standardization of diagnostic criteria of cam and pincer, still scarce and variable in the literature. Thus it will be possible to define the prevalence and natural history of femoroacetabular impingement and its relationship with hip osteoarthrosis. Aim: To determine the prevalence of cam-type and pincer-type femoroacetabular impingements in asymptomatic subjects. Patients and Methods: Were studied 106 asymptomatic subjects (65 males and 41 females) aged between 20 and 40 years. The determining condition for inclusion in the study was the absence of history of hip pain throughout life. Radiographs were obtained in anteroposterior pelvic view and Dunn 45° view. The presence of cam was determined by an angle alpha, arbitrated, 55 ° and the presence of pincer when the observed the posterior wall and / or crossover signs. Results: A prevalence of 29% of cam, and 20% and 29% of crossover sign and posterior wall sign respectively was found. At least, one of those radiographic signs of femoroacetabular impingement was found in 65% (68) of the cases. Conclusion: In conclusion, the prevalence of images of femoroacetabular impingement (65%) is above those reported in the literature. Increase of the study is necessary to verify the results found, and the performance of well-controlled prospective studies to evaluate the role of the cam and pincer in the development of osteoarthritis of the hip.

A servohydraulic hip simulator was upgraded to experimentally investigate cadaveric impingement/dislocation of the hip with clinically releveant joint motions. The resulting biomechanical analysis provided insight into risk factors for dislocation/impingement and clearly demonstrated the potential of the hip simulator as a research tool.

Femoroacetabular impingement (FAI) has been increasingly recognized as a cause of early hip osteoarthritis. FAI is characterized by pathologic contact between the femur and acetabular rim during hip join movement, caused by morphological abnormalities. Arthroscopic technique has become increasingly popular for FAI surgical treatment because of its minimal invasiveness. However, it involves cumbersome procedures and over- or under-resection are likely to occur. To tackle this issue, robot-assisted FAI arthroscopy is a well suited approach because it results in high accuracy and reproducible surgical outcomes. This dissertation provides new approaches and methods for the current challenges in the development of robot-assisted FAI arthroscopy. The study has three objectives: 1) to develop a robust calibration method for the A-mode ultrasound probe used for noninvasive bone registration, 2) to develop a bone registration simulator for verifying the registration accuracy and consistency for any given registration point-pattern, and 3) to develop a hip range of motion simulation system that returns the virtual range of motion and determines the bone resection volume. Carefully designed calibration procedures and simulation experiments have been conducted during the study of this research. From the experimental results, the developed ultrasound calibration method successfully reduces the registration errors and is proved to be robust. The results from the registration simulator indicate that the pattern with widely distributed points lead to better registration accuracy and consistency. The hip range of motion simulation system results in acceptable accuracy and successfully generates the resection volume. With further modifications, the ultrasound probe can be successfully calibrated with the developed method, and will be applied for noninvasive bone registration. The registration simulator can also be served as a useful tool for determining the optimized registration point-pattern, which can lead to reduced surgical trauma and registration time. Finally, the developed range of motion simulation system can allow the surgeon to evaluate the surgical outcome and to determine the resection volume even before the surgery begins. To conclude, this dissertation provides useful approaches, methods, and software for developing robot-assisted FAI arthroscopy.