PhD Fekete - SZIE version - 2.2 - Szent István Egyetem

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Literature review 2.2. Analytical-mechanical models of squat 2.2.1. Introduction Mathematical models mean comprehensive tools to expand the possibilities of analysing complicated structures in any field of science. The investigation of the musculoskeletal system, like those of any system, usually requires the development of a model. A model is used to answer some questions about the behaviour of a system. It may be constructed as a physical apparatus, or alternatively it may be theoretical or computational. The ability to devise the best model to answer a specific question is one of the hallmarks of excellence in scientific investigation. Neither should the model be so complex that the inputs cannot be measured, nor should it be so simple that the predictions are too obvious. Creating a model that balances these two aspects requires knowledge of modelling tools, and how they may be applied [Csizmadia and Nádori, 2003]. Naturally, it also requires judgment and experience. In order to give a hint about the modelling, five simple but concrete statements can be summarized [Csizmadia and Nádori, 2003], which will be applied in our further investigations: 1. None of the investigations – theoretical or experimental – should be overemphasised. Only the proper combination of the two leads to solution. 2. The observed phenomenon can be divided into parts. Useful information can be gained by only investigating the individual parts and not the complete system. 3. The laws of nature are constant in space, valid in every field, can be summarized in mathematical formulas, independent respectively of the observer or the state of the phenomenon. These laws are parts of the nature, not made-up mathematical formulations. 4. The model is defined by the aim of the investigation as well. The aim of the model – in the view of the related laws of nature – is to determine the behaviour of the investigated phenomenon. The knowledge, related to the phenomenon, can only be expanded by the model results. 5. Through the new models, new information can be gained regarding the phenomenon in interest, but the obtained results must be always compared to experiments. This is the adequate way to conclude whether the model is correct or not. Although, it is not mentioned as an individual statement, another relevant comment has to be added to the modelling issues. Since a model only follows some major similarity with the observed phenomenon, eventually it will not be able to describe it entirely. There is always a range where the model gives a good approximation related to the phenomenon but beyond that, due to the lack of perfect description, the obtained results are not in agreement with reality. This is the applicability range of the model. In any case, if a theoretical model is used, this range has to be appointed. It is well known, that patellofemoral problems are common causes of failure after total knee replacement (TKR). Patellar resurfacing implants have often shown loosening or wear of their polyethylene surfaces [Garcia et al., 2009, Sharkey et al., 2002]. Besides that large increases in anterior patellar strain have been reported after total knee replacements, suggesting, that joint replacements may have adverse effects on the mechanics of the extensor mechanism of the knee joint [McLain et al., 1986, Reuben et al., 1991]. – 20 –
Literature review For this reason, the acting forces in the knee joint have to be known in most of the cases of the movements. In order to address the problem regarding the kinetics of the knee joint, a comprehensive overview have been carried out about all the available (current and early) analytical-mechanical models. In this overview, the models are substantially reviewed and analyzed. At the end of each review, the important findings, related to the shortcomings or problems still undealt with, are summarized and some remarks are outlined. By this approach, the common and long-standing features of the earlier models can be utilized, the ones that are proven irrelevant disregarded, and the missing links complemented in a new analytical-kinetical model. 2.2.2. Human locomotion and kinetics Peak forces acting in the knee joint under various activities were calculated as long ago as the 1950s. Different knee models with input of gait analysis, force plate data, EMG data, or geometric measurements of the limb were used in these investigations. In order to see how the magnitude of the forces depends on the different locomotion types a table has been assembled with the type of activities and the peak patellofemoral compression forces (Table 2.1). AUTHOR ACTIVITY FLEXION F pf /BW ANGLE Bresler and Frankel, 1950 Level walking 20° 1.2 Reilly and Martens, 1972 Level walking 10° 0.5 Morra and Greenwald, 2006 Walking gait 15° 0.6 Nisell, 1985 Lifting (12.8 kg) 90° 2.2 Ericson and Nisell, 1987 Cycling 83° 1.3 Reilly and Martens, 1972 Stair walking 55° 3.3 Andriacchi et al., 1980 Stair ascent and descent 60-65° 2.1-5.7 Morra and Greenwald, 2006 Stair ascent 45° 2.5 Smidt, 1973 Isometric quads contraction 75° 2.6 Kelley et al., 1976 Rising from a chair 90° 5.5 Ellis et al., 1979 Rising from a chair 120° 3.1 Morra and Greenwald, 2006 Rising from a chair 90° 2.8 Huberti and Hayes, 1984 Isometric extension 90° 6.5 Nisell, 1985 Isometric extension 90° 9.7 Kaufman et al., 1991 Isokinetic exercise 70° 5.1 Reilly and Martens, 1972 Squatting 130° 7.6 Dahlqvist et al., 1982 Ascending/descending from squat 140° 6-7.6 Winter, 1983 Jogging 50° 7.7 Wahrenberg et al., 1978 Kicking 100° 7.8 Smith et al., 1972 Jumping - 20 Nisell, 1985 Quadriceps tendon rupture - 14.4-24.2 Zernicke et al., 1977 Patellar tendon rupture 90° 25 Table 2.1. Patellofemoral force (F pf) divided by body weight (BW) in case of different movements – 21 –
Page 1 and 2: SZENT ISTVÁN UNIVERSITY KINETICS A
Page 3 and 4: CONTENTS NOMENCLATURE AND ABBREVIAT
Page 5 and 6: NOMENCLATURE AND ABBREVIATIONS F pf
Page 7 and 8: ψ : Angle between the quadriceps t
Page 9 and 10: v CTt : Tangential velocity compone
Page 11 and 12: Introduction 1. INTRODUCTION AND OB
Page 13 and 14: 1.3. Aims of the PhD thesis Introdu
Page 15 and 16: Literature review 2. LITERATURE REV
Page 17 and 18: Literature review Figure 2.3. The f
Page 19 and 20: Literature review Figure 2.6. Patel
Page 21 and 22: Literature review Figure 2.8. Compo
Page 23: Literature review The knee carries
Page 27 and 28: Literature review Figure 2.12. Thre
Page 29 and 30: Literature review As a short overvi
Page 31 and 32: Literature review Moment arm 60 [mm
Page 33 and 34: Literature review I. They demonstra
Page 35 and 36: Literature review The presented mod
Page 37 and 38: Literature review ε angle [˚] 100
Page 39 and 40: Literature review Fpf/Fq [-] 1.2 1
Page 41 and 42: Literature review β angle [˚] Mal
Page 43 and 44: Literature review Figure 2.35. Mech
Page 45 and 46: Literature review Moment arm 60 [mm
Page 47 and 48: Literature review Let us follow the
Page 49 and 50: Literature review Finally, the pate
Page 51 and 52: Literature review Figure 2.43. Tota
Page 53 and 54: Literature review One great advanta
Page 55 and 56: Literature review Implant wear is t
Page 57 and 58: 2.3.2. General numerical models Lit
Page 59 and 60: a) The tibia plateau is a flat surf
Page 61 and 62: Literature review From their calcul
Page 63 and 64: Literature review Although a simila
Page 65 and 66: Literature review Slide/Roll [-] 1
Page 67 and 68: Literature review Figure 2.62. Mult
Page 69 and 70: Materials and Methods 3.1. Methodol
Page 71 and 72: Materials and Methods For the sake
Page 73 and 74: Materials and Methods 9 th QUESTION
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Materials and Methods 3.3. New anal
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Materials and Methods 3.3.3. Free-b
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Materials and Methods Figure 3.6. F
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Materials and Methods By the introd
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Materials and Methods 3.4. Experime
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Materials and Methods Figure 3.7. C
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Materials and Methods All of the pa
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Materials and Methods 3.4.5. Measur
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x c Materials and Methods ∑ Fi
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Materials and Methods Probability D
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Materials and Methods Figure 3.18.
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Materials and Methods By doing so,
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3.4.7.2. Steps of the approach Mate
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Materials and Methods All the funct
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Materials and Methods β [º] 40 20
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Materials and Methods If the center
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Materials and Methods By the use of
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Materials and Methods Thus, one pri
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Materials and Methods I. The patter
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3.6.3. Geometrical models Materials
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Materials and Methods − − −
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3.6.4.3. Contact [MSC.ADAMS] Materi
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Materials and Methods Besides the k
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Materials and Methods By multiplyin
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Results 4. RESULTS 4.1. Results reg
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Results This closely equal percenta
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Results Fpf/BW [-] 8 Fekete et al.
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Results In reality, human subjects
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Results 4.2. Results regarding the
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Results 0.8 Χ [-] 1 Sliding-rollin
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Results Χ [-] 1 Sliding-rolling ra
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Results Among the tested prostheses
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Results χ [-] 1 Averaged sliding-r
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Results Χ [-] 1 Sliding-rolling ra
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4.3. New scientific results Results
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Results 3 rd Thesis: Based on the m
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Conclusions and Suggestions 5. CONC
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Conclusions and Suggestions Suggest
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Summary 6. SUMMARY In this doctoral
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Appendix APPENDIX A1. Bibliography
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Appendix [31] Csizmadia B. M., Nán
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Appendix [61] Gill H. S., O’Conno
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Appendix [93] Klebanov B. M., Barla
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Appendix [123] Nägerl H., Frosch K
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Appendix [154] Reuben J. D., McDona
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Appendix [187] Wahrenberg H., Lindb
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Appendix 6. Fekete G., Kátai L.: M
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Appendix Figure 3. Setting Stitchin
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Appendix Fpf/Fq [-] 1.2 h = 6 mm h
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Appendix η1 angle [˚] 6 Hirokawa
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Appendix Figure 13. Mechanical mode
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Appendix Ψ angle [˚] 10 Van Eijde
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Appendix Figure 19. Mechanical mode
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Appendix - 177 -
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PhD Fekete - SZIE version - 2.2 - Szent István Egyetem

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