Background Musculoskeletal problems and falls are major contributors to disabilities, both globally and in East Asia and the Pacific. Osteoporosis and falls are common in the elderly. Their impact lies in the fragility fractures that result. Of these, hip fracture is the most costly, in terms of mortality, morbidity, and the medical and social care costs incurred. With an ageing population, the number of hip fractures is set to rise. Having a prediction model for outcomes will help risk stratification of patients, and aid planning of clinical care, rehabilitation and discharge. The objective of this study is to validate the Nottingham Hip Fracture Score for mortality prediction in Hong Kong. Methods This is a retrospective study of 2209 consecutive adult patients admitted to Caritas Medical Centre from 1st January 2007 to 31st December 2012. Data was collected from the Clinical Management System, a local rehabilitation unit database, and the Hong Kong Death Registry. Variables included to predict mortality were age, sex, place of residence, presence of ≤2 comorbidities, presence of cancer, and haemoglobin level on admission. Binary logistic regression was performed. A cognitive function test score is needed for full validation of the Nottingham Hip Fracture Score. This score was only available for patients admitted to the rehabilitation unit. A sensitivity analysis was therefore done. Results Presence of cancer [odds ratio 3.67 (2.26, 5.95)], male sex [odds ratio 2.32 (1.83, 2.93)], presence ≥2 comorbidities [odds ratio 1.38 (1.09, 1.74)] and age [odds ratio 1.05 (1.03, 1.06)] were associated with 1-year mortality. Low haemoglobin level on admission was found to be a poor prognostic factor in other studies, but appeared to be protective in ours [odds ratio 0.74 (0.70, 0.79)]. Admission from old age home was not statistically significant. Sensitivity analysis assuming both best and worst case scenarios for cognitive function test scores found the Nottingham Hip Fracture Score to be a poor prediction model in Hong Kong. Conclusions The Nottingham Hip Fracture Score was a poor prediction model in Hong Kong, because of the low hip fracture mortality rates in Hong Kong. To be locally useful, the score need to be re-calibrated. To reduce the burden of disability from hip fracture, prevention is important, as is helping patients to recover from their injury. Better understanding of variations in length of stay and discharge destinations between hospitals in Hong Kong may provide some insights into areas for improvement. / published_or_final_version / Public Health / Master / Master of Public Health

Falls and fall-induced fractures are very common among the elderly. Hip fractures account for most of the deaths and costs of all the fall-induced fractures. This dissertation presents a novel MEMS based human airbag system used as a hip protector. A Micro Inertial Measurement Unit (muIMU) which is based on MEMS accelerometers and gyro sensors is developed as the motion sensing part of the system. The result using this muIMU based on Support Vector Machine (SVM) training to recognize falling-motions are presented, where we showed that selected eigenvector sets generated from 200 experimental data can be separated into falling and other motions completely. For real-time recognition, the SVM filter should be embedded to a high speed DSP system for fast computation and complex filter analyses. After the simulations for SVM filter and FFT were performed on a computer simulator (TI DSP320 C6713), we used DSK6713 (DSP Starter Kit) as our target board and integrated FFT and SVM filter on the chip. The whole algorithm works well with exist sensor data. Demo shows that our DSP system can successfully classify fall and non-fall states. At the same time, the system can trigger our airbag inflation mechanism when a fall occurs. The system was shown to open the airbag in real-time and protected the experimenter's hip area. / by Shi, Guangyi. / "March 2008." / Adviser: Wen Jung Li. / Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1855. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (p. 108-111). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

published_or_final_version / Community Medicine / Doctoral / Doctor of Philosophy

Chan Cheung Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 88-90). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xii / Abbreviations and Notations --- p.xiii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background and Objective --- p.1 / Chapter 1.2 --- Contribution --- p.4 / Chapter 1.3 --- Thesis Outline --- p.5 / Chapter Chapter 2 --- System Architecture --- p.6 / Chapter 2.1 --- Conceptual Design --- p.6 / Chapter 2.2 --- Sensing Device and Fall-Detection Algorithm --- p.7 / Chapter 2.3 --- Mechanical Part --- p.10 / Chapter Chapter 3 --- Mechanical Design --- p.11 / Chapter 3.1 --- Similar Products --- p.11 / Chapter 3.1.1 --- Airbag Restraining Systems in Automobiles --- p.11 / Chapter 3.1.2 --- Airbag Jackets for Motorcycle and House Riders --- p.12 / Chapter 3.2 --- Mechanism adopted --- p.12 / Chapter 3.2.1 --- Time Requirement of Inflator --- p.12 / Chapter 3.2.2 --- Mechanism and Design --- p.13 / Chapter 3.2.3 --- Actuator --- p.14 / Chapter 3.2.4 --- Punch --- p.15 / Chapter 3.2.5 --- Airbags --- p.18 / Chapter 3.2.6 --- Other Mechanisms Tried --- p.19 / Chapter 3.3 --- Prototype --- p.21 / Chapter 3.3.1 --- Implementation --- p.21 / Chapter 3.3.2 --- Demonstration --- p.23 / Chapter Chapter 4 --- Inflation Estimation --- p.25 / Chapter 4.1 --- Theory and Model --- p.25 / Chapter 4.2 --- Validation of Model --- p.28 / Chapter 4.2.1 --- Testing Equipment --- p.28 / Chapter 4.2.2 --- Preprocessing of Pressure Sensor Outputs --- p.28 / Chapter 4.2.3 --- Validation for Basic Equations --- p.29 / Chapter 4.2.4 --- Adjustment of Discharge Coefficients --- p.36 / Chapter 4.2.5 --- Validation for Discharging to a Fixed Volume --- p.40 / Chapter 4.2.6 --- Estimation of the Size of Airbag's Leakage Hole --- p.45 / Chapter 4.2.7 --- Validation for Discharging to an Airbag --- p.47 / Chapter 4.2.8 --- Time Delay due to Addition of a Pipe --- p.52 / Chapter 4.3 --- Summary of Experiments --- p.53 / Chapter 4.4 --- Limitation of Model --- p.54 / Chapter 4.5 --- Prediction of Inflation Time and Airbag Pressure --- p.55 / Chapter 4.5.1 --- Effects of Orifice Size and Vent Size on Airbag Pressure and Volume --- p.55 / Chapter Chapter 5 --- Force Attenuation Estimation --- p.58 / Chapter 5.1 --- Theory and Model --- p.58 / Chapter 5.1.1 --- Kelvin-Voigt Model --- p.59 / Chapter 5.1.2 --- Standard Linear Solid Support Model --- p.59 / Chapter 5.2 --- Simple Testing for Validation --- p.61 / Chapter 5.3 --- Summary of Experiment --- p.64 / Chapter 5.4 --- Estimation --- p.64 / Chapter 5.4.1 --- Force Attenuation Ability of Prototype --- p.64 / Chapter 5.4.2 --- Minimum Airbag Volume and Pressure Required to Reduce the Force --- p.65 / Chapter Chapter 6 --- Future Work --- p.66 / Chapter 6.1 --- Impact Test for Airbag System --- p.66 / Chapter 6.2 --- The Effective Mass of the Target User --- p.67 / Chapter 6.3 --- The Motion Data Collection --- p.68 / Chapter 6.4 --- Modification in the Inflator --- p.69 / Chapter Chapter 7 --- Conclusion --- p.70 / Appendix A Review of Basic Thermodynamics and Fluid Dynamics --- p.72 / Chapter A.1 --- Thermodynamics --- p.72 / Chapter A.2 --- Fluid Mechanics: Incompressible and Compressible Flow --- p.75 / Appendix B Derivation of Equations --- p.77 / Chapter B.1 --- Mass Flow Rate Equations --- p.77 / Chapter B.2 --- Relationship between Rate of Changes of Airbag Pressure and Volume --- p.80 / Chapter B.3 --- Pressure Change of Compressed Gas Cylinder --- p.82 / Chapter B.4 --- Dominating Factors in the Mass Flow Rate Equation --- p.83 / Appendix C Dimensions of Inflator --- p.85 / Appendix D Experimental Data --- p.86

Sze Pan Ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 162-178). / Abstracts in English and Chinese. / ABSTRACT --- p.i / ABSTRACT (IN CHINESE) --- p.iv / ACKNOWLEGEMENT --- p.vi / TABLE OF CONTENTS --- p.viii / LIST OF FIGURES --- p.xv / LIST OF TABLES --- p.xviii / LIST OF APPENDIX --- p.xx / LIST OF ABBREVIATIONS --- p.xxi / LIST OF DEFINITIONS OF TERMS --- p.xxii / Chapter I. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Epidemiology of hip fracture among elderly worldwide --- p.1 / Chapter 1.2 --- Impact of hip fractures --- p.3 / Chapter 1.2.1 --- Mortality --- p.3 / Chapter 1.2.2 --- Hospitalization and institutionalization --- p.4 / Chapter 1.2.3 --- Morbidity --- p.4 / Chapter 1.2.4 --- Psychological impact and quality of life --- p.5 / Chapter 1.2.5 --- Financial burden --- p.6 / Chapter 1.3 --- Causes of hip fracture --- p.6 / Chapter 1.3.1 --- Mechanisms of hip fracture --- p.7 / Chapter 1.3.2 --- Degenerated protective mechanism --- p.8 / Chapter 1.3.3 --- Poor hip strength indices --- p.9 / Chapter 1.4 --- Prevention of hip fractures --- p.10 / Chapter 1.4.1 --- Reduction of the chance of lateral fall --- p.10 / Chapter 1.4.2 --- Increase hip strength indices --- p.11 / Chapter 1.4.3 --- Limitations of current strategies --- p.12 / Chapter 1.5 --- Hip protectors for prevention of hip fractures --- p.12 / Chapter 1.6 --- Effectiveness of hip protector --- p.14 / Chapter 1.6.1 --- Laboratory studies on effectiveness in force attenuation --- p.14 / Chapter 1.6.2 --- Clinical studies on prevention of hip fractures --- p.16 / Chapter 1.6.3 --- Cost-effectiveness study --- p.17 / Chapter 1.7 --- Problems on the use of hip protectors --- p.19 / Chapter 1.7.1 --- Discomfort --- p.19 / Chapter 1.7.2 --- Extra effort in wearing --- p.20 / Chapter 1.7.3 --- Appearance after wearing --- p.21 / Chapter 1.7.4 --- Urinary incontinence --- p.22 / Chapter 1.7.5 --- Oth er problems --- p.23 / Chapter 1.8 --- Acceptance and Compliance of hip protectors --- p.23 / Chapter 1.8.1 --- Acceptance --- p.23 / Chapter 1.8.2 --- Compliance --- p.24 / Chapter 1.9 --- Strategies to improve compliance of hip protector --- p.25 / Chapter 1.9.1 --- Better design of hip protector --- p.25 / Chapter 1.9.2 --- Encouragement/support to the user --- p.26 / Chapter 1.9.3 --- Support from nursing staff/carer --- p.27 / Chapter 1.10 --- Rationale and objectives of present study --- p.28 / Chapter II. --- METHODOLOGY --- p.36 / Chapter 2.1 --- Development of hip protector --- p.36 / Chapter 2.1.1 --- Design of the pads --- p.36 / Chapter 2.1.2 --- Design of the pants --- p.38 / Chapter 2.1.2.1 --- Fabric materials --- p.38 / Chapter 2.1.2.2 --- Anthropometric measurement --- p.42 / Chapter 2.1.2.3 --- Pattern design --- p.43 / Chapter 2.1.3 --- Trial use of hip protector --- p.43 / Chapter 2.1.4 --- Calculation and statistical method --- p.43 / Chapter 2.2 --- Mechanical test on force attenuation properties --- p.44 / Chapter 2.2.1 --- Testing system --- p.44 / Chapter 2.2.2 --- Simulation of impact force and identification of dropping height --- p.45 / Chapter 2.2.3 --- Testing method --- p.46 / Chapter 2.2.4 --- Calculation and statistical method --- p.47 / Chapter 2.3 --- Compliance study --- p.47 / Chapter 2.3.1 --- Setting --- p.47 / Chapter 2.3.2 --- Subjects --- p.48 / Chapter 2.3.3 --- Study design --- p.49 / Chapter 2.3.4 --- Implementation procedure and intervening Program --- p.49 / Chapter 2.3.4.1 --- Liaison with the heads and responsible staff in the elderly hostels --- p.49 / Chapter 2.3.4.2 --- Education program for hostel staff --- p.50 / Chapter 2.3.4.3 --- Education program for elderly subjects --- p.50 / Chapter 2.3.4.4 --- Fall and fracture risk counseling --- p.51 / Chapter 2.3.4.5 --- Consent and Ethical approval --- p.51 / Chapter 2.3.4.5 --- Provision of hip protector and training program on wearing hip protector --- p.51 / Chapter 2.3.4.6 --- Follow up and encouragement on the use of hip protector --- p.52 / Chapter 2.3.5 --- Outcome measures --- p.52 / Chapter 2.3.5.1 --- Primary outcome --- p.52 / Chapter 2.3.5.2 --- Secondary outcomes --- p.53 / Chapter 2.3.6 --- Measurement method --- p.55 / Chapter 2.3.6.1 --- Compliance --- p.55 / Chapter 2.3.6.2 --- Falls and fractures incidence --- p.56 / Chapter 2.3.6.3 --- Adverse effect and feedback after wearing hip protector --- p.56 / Chapter 2.3.6.4 --- Fear of fall --- p.57 / Chapter 2.3.6.5 --- Fall and fracture history --- p.57 / Chapter 2.3.6.6 --- Medical co-morbidities --- p.58 / Chapter 2.3.6.7 --- Presence of urinary incontinence --- p.58 / Chapter 2.3.6.8 --- Functional level --- p.58 / Chapter 2.3.6.9 --- Hand function --- p.58 / Chapter 2.3.6.10 --- Mobility --- p.59 / Chapter 2.3.6.11 --- Cognitive function --- p.59 / Chapter 2.3.7 --- Sample size calculation --- p.59 / Chapter 2.3.8 --- Calculation and Statistical method --- p.60 / Chapter III. --- RESULTS --- p.73 / Chapter 3.1 --- Design of hip protector --- p.73 / Chapter 3.1.1 --- The design of pants --- p.73 / Chapter 3.1.1.1 --- The fabric materials --- p.73 / Chapter 3.1.1.2 --- The size of the pants --- p.74 / Chapter 3.1.2 --- The design of pads --- p.75 / Chapter 3.1.2.1 --- Thickness of silicon padding --- p.75 / Chapter 3.1.1.2 --- Dimension of the hard shield --- p.75 / Chapter 3.2 --- Mechanical test on force attenuation properties of the pads --- p.76 / Chapter 3.2.1 --- Impact force --- p.76 / Chapter 3.2.2 --- Impact duration --- p.78 / Chapter 3.2.3 --- Selection of th e prototype --- p.78 / Chapter 3.3 --- Compliance study --- p.79 / Chapter 3.3.1 --- Demograph ics --- p.79 / Chapter 3.3.2 --- Primary outcome --- p.79 / Chapter 3.3.2.1 --- Initial acceptance rate --- p.79 / Chapter 3.3.2.2 --- Compliance rate --- p.79 / Chapter 3.3.2.3 --- Percentage of people wearing hip protector across the study period --- p.81 / Chapter 3.3.2.4 --- Percentage of protected fall --- p.81 / Chapter 3.3.3 --- Secondary outcomes --- p.81 / Chapter 3.3.3.1 --- Fall and related injury among the subjects in the study period --- p.81 / Chapter 3.3.3.2 --- Reasons for non-acceptance --- p.82 / Chapter 3.3.3.3 --- Feedback in using hip protector --- p.84 / Chapter 3.3.3.4 --- Factors associated with compliance and non-compliance (feedback in wearing hip protector) --- p.84 / Chapter 3.3.3.5 --- Factors associated with compliance and non-compliance (subject characteristics) --- p.85 / Chapter 3.3.3.6 --- Effect on mobility after wearing hip protector --- p.85 / Chapter 3.3.3.7 --- Fear of fall after wearing hip protector --- p.85 / Chapter IV. --- DISCUSSION --- p.123 / Chapter 4.1 --- Development of a hip protector for Chinese elderly --- p.124 / Chapter 4.1.1 --- Successful modifications made to the pads --- p.124 / Chapter 4.1.1.1 --- More comfort to wear with silicon cushioning materials added --- p.124 / Chapter 4.1.1.2 --- Better mechanical properties with semi-flexible plastic and silicon pad --- p.125 / Chapter 4.1.1.3 --- Smaller in dimension of the present model might improve appearance after wearing --- p.127 / Chapter 4.1.2 --- No significant improvement on compliance with modification of the pants --- p.128 / Chapter 4.2 --- Sufficient mechanical properties of hip protector demonstrated --- p.129 / Chapter 4.2.1 --- Mechanical test set up --- p.130 / Chapter 4.2.2 --- Mechanism of force attenuation --- p.132 / Chapter 4.3 --- No significant improvement on compliance shown --- p.134 / Chapter 4.4 --- Compliance at night time better than other studies --- p.136 / Chapter 4.5 --- Determinants of compliance mostly related to subjects' feedback of using hip protector rather than on their characteristics --- p.137 / Chapter 4.6 --- Better compliance observed in hostel with higher staff-to-subject ration and with occupational therapist as contact person --- p.138 / Chapter 4.7 --- Better acceptance rate of hip protector shown in the present study --- p.139 / Chapter 4.8 --- Identification of factors influencing acceptance --- p.139 / Chapter 4.9 --- Percentage of protected fall was higher than mean compliance --- p.141 / Chapter 4.10 --- No hip fracture occurred while subjects wearing hip protector --- p.141 / Chapter 4.11 --- Decreased fear of falling after wearing hip protector --- p.142 / Chapter 4.12 --- Limitation --- p.142 / Chapter 4.13 --- Recommendation --- p.143 / Chapter V. --- CONCLUSION --- p.146 / Chapter VI. --- APPENDIX --- p.148 / Chapter VII. --- BIBLIOGRAPHY --- p.162 / Chapter VIII. --- PUBLICATIONS --- p.179