Chronic Malfunction of the Patellofemoral Joint: the Causal Role

CHRONIC MALFUNCTION OF THE PATELLOFEMORAL JOINT: THE CAUSAL ROLE OF ABNORMALITIES OF QUADRICEPS ACTION AND POOR TRACKING by GILLIAN MARY MORRISH A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy in the University of London Institute of Human Performance University College London Royal National Orthopaedic Hospital Stanmore Middlesex The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the author. ProQuest Number: 10106722 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest. ProQuest 10106722 Published by ProQuest LLC(2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. Microform Edition © ProQuest LLC. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 ABSTRACT Malalignment of the patella has been implicated in patellofemoral problems, but the aetiology of the condition is not well understood. Efforts have been made in this thesis to study the underlying abnormalities, both biomechanical and of muscle function, which might contribute to this syndrome. The function of 72 patients with chronic anterior knee pain, where the onset has been insidious rather than a direct response to trauma, has been studied and compared with groups of normal subjects. Many of the experiments undertaken relate to the muscle activity, in the portions of the quadriceps thought to affect the position of the patella. The changes which have been seen, have then been correlated with other abnormalities, in order to understand their place in the pathology of this condition. Other experiments were done only with groups of normal subjects, and relate to the normal functioning of the quadriceps, in different conditions. Particular areas of study have been:- 1. Signs and symptoms have been recorded in the patient group, and correlated with other abnormalities seen. The intensity of pain and extent of disability have been recorded by means of a questionnaire given to each patient. 2. The quadriceps strength of both lower limbs has been assessed by means of a maximal voluntary extensor effort, isometrically performed, and compared with the predicted strength based on the height of the individual. 3. EMG activity of the oblique fibres of vastus medialis and vastus lateralis as well as rectus femoris, was compared with extensor force at different knee angles, isometrically, isokinetically, and dynamically. Evidence of reflex inhibition due to pain and other factors has been sought. Effort has been made to understand the changes in muscle activation of the patient group, by studying the quadriceps activation of a group of normal subjects in different knee positions and at different velocities. 4. The biomechanics of the whole of the lower limb has been studied at rest, by surface markings and range of movement of the various joints. The effect of this on the gait pattern has been studied by video recording of the patient group, as well as normal subjects. 5. A study of the position of the patella by computerised tomography, with respect to its articulation with the lower end of the femur, in a small group of patients and also with normal subjects. 6. A small group of patients was tested before and after 6 weeks of conservative treatment, in order to ascertain which parameters were capable of change. From the questionnaire, the changes noted were correlated with the extent of disability and intensity of pain. 7. A study of the normal anatomy of the joint in one cadaver has been made, so that the effects of the observed biomechanical factors could be more fully understood. Not only was there a considerable loss of quadriceps strength in the patient group, but the EMG studies showed abnormalities of quadriceps activation, which were particularly evident in the oblique fibres of the vasti. There were also differences in the alignment of the long lower limb bones in these individuals, which were not apparent in the normal subjects. Correlation among different results did not show direct correlation of one pathological finding with another. They suggest that this syndrome is multifactorial. The studies on normal subjects show that in some conditions. changes in rotatation of the hip and knee do alter the way in which the vasti are activated. ACKNOWLEDGEMENTS I would like to express my sincere thanks to the following people:- my supervisor, Professor Roger Woledge, for all his help, patience and advice. KQs exceptional breadth of knowledge, both scientific and mathematical, has been invaluable. I would also like to thank other members of the staff of the Institute of Human Performance, particularly Andrew Pinder, Suzanne Phillips, and Deirdre Birtles and Tony Christopher. I also record my thanks to my previous supervisor Professor David Jones for his help in setting up and starting the project, also Paul Sacco, whose help was invaluable in mastering the equipment, and to Dave McKintyre for his computer expertise, to Geoffrey Cusick, who heads the Medical Instrumentation Services of the Middlesex Hospital, for designing equipment, to the doctors who sent me patients, and the physiotherapy staff of the Middlesex Hospital and Royal National Orthopaedic Hospital, to the Sir Jules Thorn Charitable Trust who financed the project, to all the patients and all the normal subjects who gave up so much time for the project, and lastly, but certainly not least, to my husband, John, for his love and support. TABLE OF CONTENTS ABSTRACT 2 ACKNOWLEDGEMENTS 5 CONTENTS 6 LIST OF FIGURES 10 LIST OF TABLES 16 TABLE OF CONTENTS 1. INTRODUCTION AND LITERATURE REVIEW 19 1.1. General View of Patellofemoral Disorders 1.2. Anatomy and Normal Function of the Patellofemoral Joint 1.3. Movements of the Patellofemoral Joint 1.4. Muscles Acting on the Patella 1.5 Biomechanical Effects on the Joint 1.5.1. Normal Function 1.5.2. Patellofemoral Contact Pressure 1.5.3. Biomechanical Effects of Long Bone Alignment 1.5.4. Iliotibial Band or Tract 1.5.5. Lower Leg and Foot Alignment. 1.6. Pathology of the Disorder CHAPTER II 57 METHODS USED IN THESE EXPERIMENTS 2.1. Choice of Subjects 2.2. E.M.G. Recording 2.2.1. Method of Finding the Motor Points 2.2.2. Description and Use of the EMG Equipment 2.2.3. Calibration of Amplitude of the EMG Signal 2.2.4. Calibration of EMG Amplifier Integrator 2.2.5. Measurement of Skin Resistance Using the Same Preparation as the EMG Recording 2.2.6. Cross Correlation of the EMG signals 2.2.7. Estimation of the Depth of Adipose Tissue at the Sites of EMG Recording 2.3. Cybex II Plus Dynamometer 2.3.1. Description of the Cybex 2.3.2. Calibration of the Cybex 2.4. Statistical Methods 2.5. Other Tests CHAPTER III 93 EXPERIMENT TO TEST MAXIMUM ISOMETRIC STRENGTH IN A GROUP OF PATIENTS WITH CHRONIC PATELLOFEMORAL PROBLEMS 3.1. Experiment to Compare the Force Exerted by the Quadriceps at Three Different Lengths 3.2. Experiment to Test the MVC of Patients with Chronic Patellofemoral Problems CHAPTER IV 111 A COMPARISON OF THE ACTIVATION OF MUSCLES MOVING THE PATELLA IN NORMAL SUBJECTS AND IN PATIENTS WITH CHRONIC PATELLOFEMORAL PROBLEMS 4.1. Experiment to Test the Activation of the Oblique Fibres of Vastus Medialis and Vastus Lateralis at 20 degrees of Knee Flexion 4.2. Activation of VMO in the Group of Patients with Unilateral Symptoms CHAPTER V 125 EXPERIMENT TO TEST PATIENTS WITH PATELLOFEMORAL PROBLEMS ISOKINETICALLY FROM 0 TO 90 DEGREES OF KNEE FLEXION 5.1. Experiment to Investigate the Effect of Knee Angle on the Size of the Superimposed Action Potential Obtained from the Three Recording Sites 5.2. Experiment to Test whether there is Inhibition of VLO and VLO during Isokinetic testing at 60°/s in Patients with Patellofemoral Problems 5.3. Quadriceps/Hamstring Ratio 5.4 Quadriceps Activity during Flexion of the Knee CHAPTER VI 159 CHANGES IN VMO ACTIVATION AT DIFFERENT RATES OF APPLICATION OF FORCE AND DIFFERENCES IN KNEE POSITION 6.1. Experiment to See whether there is a Difference of Activation of the Oblique Fibres of the Vasti compared with the Long Fibres, at Slow Activation Rates. 6.2. Experiment to Investigate any Differences in V M O. and V L O Action in Changes of Rotation of the Hip with the knee flexed to 20°, and with Changes of Rotation of the Knee Flexed to 90° 6.3. Experiment to Investigate whether Changes in the Activation of V.M.O. in External Rotation of the Hip at 20° of Flexion of the Knee are Paralleled by Changes in VML CHAPTER VII 194 EXPERIMENT TO TEST THE LENGTH OF THE HAMSTRINGS AND PLANTARFLEXORS IN PATIENTS WITH PATELLOFEMORAL DISORDERS COMPARED WITH NORMAL SUBJECTS 7.1. Experiment to investigate the length of the hamstrings 7.2 Experiment to investigate the length of the plantarflexors CHAPTER VIII 203 BIOMECHANICAL MEASUREMENTS 8.1 External and internal rotation of the hip 8.2. External tibial torsion CHAPTER IX 220 ASSESSMENT OF PATELLA POSITION BY COMPUTERISED TOMOGRAPHY CHAPTER X 234 THE CASE HISTORIES OF FOUR PATIENTS CHAPTER XI 249 CORRELATION AMONG DIFFERENT RESULTS REFERENCES 258 APPENDIX I 290 Glossary of Abbreviations and Terms Used in this Thesis APPENDIX II (attached to back cover) An example of CT obtained. APPENDIX III Final Draft of Paper for Publication LIST OF FIGURES Figure 1.1: Right Patella (posterior aspect).

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