Clinical Biomechanics and its Implications on Diabetic Foot [1st ed.] 9789811536809, 9789811536816

This book presents essential information on biomechanical features of the diabetic foot, which could help to minimize th

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Table of contents :
Front Matter ....Pages i-xxiv
Introduction and Understanding of the Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 1-11
Epidemiology and Current Status of Diabetes Mellitus and Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 13-22
Pathomechanics of Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 23-31
Patient’s Perspective on Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 33-37
Clinician’s Perspective on Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 39-48
Diabetic Foot Complications: Foot Deformities, Peripheral Vascular Disease, Claudication, Foot Ulcers, and Amputation (Animesh Hazari, G. Arun Maiya)....Pages 49-58
Diabetic Foot Ulcers: Case Presentations (Animesh Hazari, G. Arun Maiya)....Pages 59-63
Biomechanics of Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 65-73
Biomechanical Characteristics of Diabetic Foot Syndrome Among Indians with Diabetes Peripheral Neuropathy (Animesh Hazari, G. Arun Maiya)....Pages 75-82
Role of Plantar Pressure in Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 83-86
Biomechanical Assessment and Implications in Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 87-99
Important Biomechanical Features and Findings in Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 101-138
Predictors of Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 139-144
Management of Diabetic Foot Syndrome (Animesh Hazari, G. Arun Maiya)....Pages 145-166
Back Matter ....Pages 167-176
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Clinical Biomechanics and its Implications on Diabetic Foot Animesh Hazari G. Arun Maiya

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Clinical Biomechanics and its Implications on Diabetic Foot

Animesh Hazari • G. Arun Maiya

Clinical Biomechanics and its Implications on Diabetic Foot

Animesh Hazari LFAMS, Lovely Professional University Jalandhar Punjab India

G. Arun Maiya Centre for Diabetic Foot Care and Research, MAHE Manipal Karnataka India

ISBN 978-981-15-3680-9    ISBN 978-981-15-3681-6 (eBook) https://doi.org/10.1007/978-981-15-3681-6 © Springer Nature Singapore Pte Ltd. 2020 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Foreword

Diabetes is a major public health problem of global importance. With the increase in the age of the global population, the incidence of this chronic complex metabolic disease is growing in alarming proportions. The biomechanics of the diabetic foot is altered and maladaptive. We lack a thorough understanding of the functional consequences of limb salvage. We currently rely on observation and descriptive data pertaining to the biomechanics of the diabetic foot. Technology has driven our ability to objectively describe the biomechanics of the diabetic foot. Dynamic segmental and gait analyses in conjunction with peak plantar pressure measurements have provided valuable insights. The biomechanical pathogenesis of a chronic ulceration that necessitates limb salvage is difficult to capture. Ultimately, a better understanding of the biomechanics of the diabetic foot would allow us to better select the most appropriate treatment regime to follow and thus save the diabetic foot from amputation. As the founder and president of Indian Podiatry Association, I have always promoted and encouraged our members to “think out of the box,” come up with new treatment regimes for medical healthcare, and work toward the motto we follow— save limb amputation. I am delighted to write the foreword to this provocative monograph, which sheds light on a different approach to the biomechanics of the diabetic foot. Dr. Arun Maiya whom I know for many years is a senior advisor to IPA and President of Karnataka Chapter of IPA. He is a national figure in his field and is best suited for the Diabetic Foot Management book which he and Dr. Animesh Hazari have written. I hope many students and doctors all across will benefit from this book. I wish Dr. Arun G. MaIya and Dr. Animesh Hazari great success, in their efforts and hope they find a large number of followers to this new approach to Clinical Biomechanics and its Implications on Diabetic Foot. A. P. S. Suri Diabetic Footcare Centre New Delhi, India Indian Podiatry Association New Delhi, India

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Preface by Dr. Animesh Hazari

The interest of being a healthcare professional with an expertise in diabetic foot syndrome was recognized in my early childhood at the age of 13 years, when I lost my grandfather due to diabetic foot complications. It was very difficult to understand at that time “how a small nail in the feet could become such a serious issue and lead to sudden death of an individual.” From that instance, it was my dream to work and write a book and present some valuable information in the area of diabetic foot syndrome. The idea of writing this book started in 2017 during my Ph.D when I published few articles in reputed journals and got excellent appraisal for the work. All the information provided in this book is original with an experience of understanding the topic in depth, evolved during my Ph.D research work among Indian population. In India, diabetic foot syndrome has not been taken very seriously till date, and this is my attempt to serve the people of the nation through my personal and rigorous scientific observations. I believe that having saved even one life through the information presented in this book could make our research work priceless. There are a few people I would like to acknowledge as I strongly believe that they have a direct or indirect role in the completion of this task. First of all, my grandfather “Late Mr. Pashupati Nath Jha” who was an inspiration for understanding the topic with immense seriousness. Following him, I would like to thank my parents “Mr. Krishna Kumar Hazari and Mrs. Rita Hazari” for providing me an opportunity for the highest education at the national and international platforms. Without their sacrifice and vision, I would stand nowhere. Having recalled parents and almighty for their seamless blessings, I would like to recall the support of my wife “Mrs. Rakhi Hazari” standing strong at all times through the troughs and crests of my life. Nevertheless being blessed with the most adorable daughter “Anika” who may have suffered with negligence and limited affection at times of my busy work, I thank her for understanding father’s priority. It is the blessing of my supervisor Dr. G. Arun Maiya and co-supvisor for Ph.D, Dr. Shivashankara K N who have supported me throught my academic carrer while also providing deep insights and contribution to the book through his efficient clinical expertise in Diabetes Mellitus. I have also been blessed with loving and affectionate companionship with friends like Dr. Shashi, Dr. Stephen, Dr. Sampath, Dr. Esha, Dr. Parmeshwara, Dr. Hrishikesh,

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Preface by Dr. Animesh Hazari

Dr. Anujot Kaur, Dr. Manju, Dr. Bhanu Thapar, Dr. Prashant, Mr. Digvijay Chauhan and Dr. Digpal Ranawat. Also from the deepest core of my heart, I am grateful to all my patients who provided their consent for being part of my research work. It is a pleasure to acknowledge my students like Riya Brahmi, Prishita Kumar, and Sushant Chahal who have supported this book through their contribution in drawing the original pictures. At last I would also like to thank all my well wishers who believed in my potential and all the critics who made me push myself harder and stronger and keep striving for the best. “Aim! Assess! Acknowledge!” Punjab, India

Animesh Hazari

Preface by Dr. Arun Maiya

Diabetic foot assessment and care is one of the upcoming multidisciplinary speciality in clinical practice and academics. Although there are a large number of books on diabetic foot care, very few are targeted at clinical biomechanics and its implications on diabetic foot syndrome. This book is designed to fill the gap and make the interpretation of the biomechanics in diabetic foot syndrome as simple as possible for various health care professionals. Even though diabetes and diabetic foot complications in India are increasing, there is a need for capacity building of health care professionals in the assessment and management of diabetic foot syndrome. Based on our large community-based diabetic foot research funded by the World Diabetes Foundation, we observed that there is a need for proper training of health care professionals in the management of diabetic foot syndrome. Therefore, this book should remain a useful aid for all professionals, students, and researchers working in the field of diabetic foot syndrome. I would like to thank my lead author Dr. Animesh Hazari for taking the initiative to write the book, and I would like to thank all my well-wishers who believed in my academic and research experience and expertise in the field. I would like to thank my institution and university for the continued support in our entire academic and research endeavors and for the strong support. Manipal, India

G. Arun Maiya

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Contents

1 Introduction and Understanding of the Diabetic Foot Syndrome��������   1 1.1 Classification of Diabetic Foot������������������������������������������������������������   2 1.1.1 Wagner’s Classification����������������������������������������������������������   2 1.1.2 University of Texas (Armstrong)��������������������������������������������   4 1.1.3 PEDIS Classification of Diabetic Foot ����������������������������������   4 1.1.4 SINDBAD Classification��������������������������������������������������������   9 1.2 Neuropathic Foot��������������������������������������������������������������������������������  10 1.2.1 Traumatic Diabetic Foot ��������������������������������������������������������  11 1.2.2 Neuroischemic Foot����������������������������������������������������������������  11 References����������������������������������������������������������������������������������������������������  11 2 Epidemiology and Current Status of Diabetes Mellitus and Diabetic Foot Syndrome��������������������������������������������������������������������  13 2.1 Etiological Classification of DM��������������������������������������������������������  13 2.1.1 Type 1 Diabetes Mellitus (T1DM)������������������������������������������  13 2.1.2 Type 2 Diabetes Mellitus (T2DM)������������������������������������������  13 2.1.3 Gestational Diabetes Mellitus ������������������������������������������������  14 2.1.4 Other Specific Types ��������������������������������������������������������������  14 2.2 Epidemiology of Type 2 Diabetes Mellitus����������������������������������������  14 2.3 Diabetes Peripheral Neuropathy ��������������������������������������������������������  16 2.3.1 Acute Sensory Neuropathy ����������������������������������������������������  16 2.3.2 Chronic Sensorimotor Neuropathy ����������������������������������������  16 2.3.3 Length-Dependent Diabetic Polyneuropathy��������������������������  17 2.3.4 Autonomic Neuropathy����������������������������������������������������������  17 2.4 Prevalence of DPN������������������������������������������������������������������������������  17 2.5 Epidemiology of Foot Complications in Type 2 Diabetes Mellitus����  18 2.5.1 Prevalence of Painful Neuropathy (pDPN)����������������������������  20 2.6 Mortality Rate Due to Diabetes Mellitus and Diabetic Foot Syndrome��������������������������������������������������������������������������������������������  20 References����������������������������������������������������������������������������������������������������  21 3 Pathomechanics of Diabetic Foot Syndrome ������������������������������������������  23 3.1 Etiopathogenesis of Diabetic Foot Syndrome������������������������������������  23 3.2 Neurological Mechanism of Diabetic Foot Syndrome ����������������������  25 3.3 Neurological Features of Diabetic Foot Syndrome����������������������������  26 xi

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3.4 Vascular Mechanism of Diabetic Foot Syndrome������������������������������  27 3.5 Vascular Features of Diabetic Foot Syndrome������������������������������������  27 3.6 Musculoskeletal Mechanism of Diabetic Foot Syndrome������������������  27 3.7 Musculoskeletal Features of Diabetic Foot Syndrome ����������������������  29 3.8 Biomechanical Mechanism of Diabetic Foot Syndrome��������������������  29 References����������������������������������������������������������������������������������������������������  30 4 Patient’s Perspective on Diabetic Foot Syndrome����������������������������������  33 4.1 Social Impact of DFS��������������������������������������������������������������������������  33 4.2 Psychosocial Issues����������������������������������������������������������������������������  34 4.3 Quality of Life and Diabetic Foot ������������������������������������������������������  34 4.4 Economic Burden��������������������������������������������������������������������������������  35 4.5 Morbidity and Mortality Related to DFS��������������������������������������������  36 4.6 Painful Neuropathy ����������������������������������������������������������������������������  36 References����������������������������������������������������������������������������������������������������  37 5 Clinician’s Perspective on Diabetic Foot Syndrome ������������������������������  39 5.1 Diagnostic Criteria for Type 2 DM ����������������������������������������������������  39 5.1.1 Fasting Blood Sugar Level (FBS) ������������������������������������������  39 5.1.2 Postprandial Blood Sugar Level (PPBS)��������������������������������  40 5.1.3 Random Blood Sugar Level (RBS)����������������������������������������  40 5.1.4 Glycated Hemoglobin (HbA1c)����������������������������������������������  40 5.2 Screening for Diabetic Foot Syndrome����������������������������������������������  40 5.3 Diabetes Peripheral Neuropathy Assessment��������������������������������������  40 5.3.1 Sensory Neuropathy Assessment��������������������������������������������  41 5.3.2 Motor Neuropathy������������������������������������������������������������������  42 5.3.3 Autonomic Neuropathy����������������������������������������������������������  42 5.3.4 Neuropathy Scales and Screening Tools��������������������������������  42 5.3.5 Nerve Conduction Velocity ����������������������������������������������������  43 5.3.6 Electromyography������������������������������������������������������������������  44 5.4 Vascular Assessment ��������������������������������������������������������������������������  44 5.5 Dermatological Assessment����������������������������������������������������������������  44 5.6 Musculoskeletal Assessment��������������������������������������������������������������  45 5.6.1 Strength of Foot and Lower Limb Muscles����������������������������  46 5.6.2 Muscle Length������������������������������������������������������������������������  46 5.6.3 Balance and Coordination������������������������������������������������������  47 References����������������������������������������������������������������������������������������������������  47 6 Diabetic Foot Complications: Foot Deformities, Peripheral Vascular Disease, Claudication, Foot Ulcers, and Amputation ������������  49 6.1 Background ����������������������������������������������������������������������������������������  49 6.2 How Does a Diabetic Foot Complication Occur?������������������������������  49 6.3 Etiological Classification of Diabetic Foot Complications����������������  50 6.3.1 Diabetic Neuropathy ��������������������������������������������������������������  50 6.3.2 Diabetic Vascular Problems����������������������������������������������������  51 6.4 Common Foot Deformities ����������������������������������������������������������������  51 6.4.1 Dry Skin and Diabetic Dermopathy����������������������������������������  51

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6.4.2 Deep Fissures��������������������������������������������������������������������������  51 6.4.3 Nail Bed Infections ����������������������������������������������������������������  53 6.4.4 Clawing of Toes����������������������������������������������������������������������  53 6.4.5 Hammer Toes��������������������������������������������������������������������������  53 6.4.6 Hallux Valgus��������������������������������������������������������������������������  53 6.4.7 Hallux Rigidus������������������������������������������������������������������������  53 6.4.8 Charcot Foot����������������������������������������������������������������������������  55 6.5 Common Foot Complications ������������������������������������������������������������  56 6.5.1 Peripheral Vascular Disease����������������������������������������������������  56 6.5.2 Diabetic Foot Ulcers ��������������������������������������������������������������  56 6.5.3 Gangrene and Diabetic Foot Amputation ������������������������������  57 References����������������������������������������������������������������������������������������������������  58 7 Diabetic Foot Ulcers: Case Presentations������������������������������������������������  59 7.1 Patient 1����������������������������������������������������������������������������������������������   59 7.2 Patient 2����������������������������������������������������������������������������������������������   60 7.3 Patient 3����������������������������������������������������������������������������������������������   61 7.4 Patient 4����������������������������������������������������������������������������������������������   63 8 Biomechanics of Diabetic Foot Syndrome ����������������������������������������������  65 8.1 Background ����������������������������������������������������������������������������������������  65 8.2 Biomechanics of Foot and Ankle Joint ����������������������������������������������  66 8.3 Arthrokinematics at Ankle and Foot Complex ����������������������������������  66 8.3.1 Talocrural Joint ����������������������������������������������������������������������  66 8.3.2 Subtalar Joint��������������������������������������������������������������������������  66 8.3.3 Midtarsal Joint������������������������������������������������������������������������  66 8.3.4 Lisfranc Joint��������������������������������������������������������������������������  67 8.3.5 Metatarsophalangeal and Interphalangeal Joints��������������������  67 8.4 Closed Kinematic-Kinetic Chain��������������������������������������������������������  67 8.5 Biomechanics in Gait Among Diabetes Mellitus��������������������������������  67 8.5.1 Limited Range of Motion�������������������������������������������������������  69 8.5.2 Muscular Forces at Foot����������������������������������������������������������  69 8.6 Role of Foot Arches in Diabetic Foot Biomechanics��������������������������  70 8.6.1 Functional Foot Types������������������������������������������������������������  70 References����������������������������������������������������������������������������������������������������  73 9 Biomechanical Characteristics of Diabetic Foot Syndrome Among Indians with Diabetes Peripheral Neuropathy����������������������������������������  75 9.1 Background ����������������������������������������������������������������������������������������  75 9.2 Clinical and Biomechanical Characteristics ��������������������������������������  76 9.2.1 Autonomic Findings ��������������������������������������������������������������  77 9.2.2 Motor Findings ����������������������������������������������������������������������  77 9.3 Biomechanical Characteristics and Clinical Correction ��������������������  79 9.3.1 Kinetics and Kinematics ��������������������������������������������������������  79 9.3.2 Gait Characteristics����������������������������������������������������������������  81 References����������������������������������������������������������������������������������������������������  82

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10 Role of Plantar Pressure in Diabetic Foot Syndrome ����������������������������  83 10.1 Evidence for Role of Plantar Pressure in Diabetic Foot ������������������  84 10.2 Plantar Pressure in Relation to Plantar Fat Pad Thickness ��������������  85 10.3 Plantar Pressure in Relation to Foot Type����������������������������������������  85 References����������������������������������������������������������������������������������������������������  86 11 Biomechanical Assessment and Implications in Diabetic Foot Syndrome����������������������������������������������������������������������������������������������������  87 11.1 Clinical Biomechanical Foot Analysis����������������������������������������������  87 11.1.1 Biomechanical Assessment for Muscle Strength����������������  87 11.1.2 Biomechanical Assessment for Muscle Length ������������������  88 11.1.3 Biomechanical Assessment for Foot Arch ��������������������������  88 11.1.4 Assessment for Foot Deformity ������������������������������������������  89 11.1.5 Footwear Examination ��������������������������������������������������������  89 11.1.6 Assessment of First Ray and Fifth Ray��������������������������������  90 11.1.7 Q Angle��������������������������������������������������������������������������������  90 11.1.8 Postural Examination ����������������������������������������������������������  90 11.2 Advanced Tools for Kinetic Analysis ����������������������������������������������  91 11.3 Advanced Tools for Kinematic Analysis������������������������������������������  91 11.4 Implication of Biomechanical Assessment on DFS��������������������������  97 References����������������������������������������������������������������������������������������������������  98 12 Important Biomechanical Features and Findings in Diabetic Foot Syndrome���������������������������������������������������������������������������������������������������� 101 12.1 Background �������������������������������������������������������������������������������������� 101 12.2 Normal Joint Biomechanics During Gait������������������������������������������ 102 12.3 Findings from Kinematic Analysis �������������������������������������������������� 106 12.3.1 Joint Angles�������������������������������������������������������������������������� 106 12.3.2 Joint Angular Velocity���������������������������������������������������������� 114 12.3.3 Joint Acceleration���������������������������������������������������������������� 115 12.4 Findings from Kinetic Analysis�������������������������������������������������������� 116 12.5 Interpretation of Factors Causing Altered Foot Kinematics in Diabetes Mellitus�������������������������������������������������������������������������� 124 12.6 Interpretation of Factors Causing Altered Foot Kinetics in Diabetes Mellitus�������������������������������������������������������������������������� 131 References���������������������������������������������������������������������������������������������������� 135 13 Predictors of Diabetic Foot Syndrome ���������������������������������������������������� 139 13.1 Predictors of Diabetic Foot Ulceration: Regression Model of Diabetic Foot Syndrome�������������������������������������������������������������� 139 References���������������������������������������������������������������������������������������������������� 144

Contents

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14 Management of Diabetic Foot Syndrome������������������������������������������������ 145 14.1 Preventive Approach ������������������������������������������������������������������������ 145 14.1.1 Step by Step Foot Care�������������������������������������������������������� 145 14.1.2 Foot Wear Assessment �������������������������������������������������������� 148 14.2 Detailed Foot Assessment as Preventive Approach�������������������������� 155 14.2.1 A Comprehensive Assessment Tool for Diabetic Foot Syndrome (N4PARK)���������������������������������������������������������� 155 14.2.2 Part A: Neurological Assessment���������������������������������������� 156 14.2.3 Part B: Musculoskeletal Assessment����������������������������������� 157 14.2.4 Part C: Vascular/Dermatological Assessment���������������������� 159 14.2.5 Part D: Footwear Assessment �������������������������������������������� 160 14.2.6 Part E: Functional and Pain Assessment������������������������������ 160 14.3 Curative Approach���������������������������������������������������������������������������� 160 14.3.1 Influence of Topical Warm Oxygen Therapy on Grade 1 Diabetic Foot Ulcer ������������������������������������������ 160 14.3.2 Wound Healing by Photobiomodulation on Critical Ischemic Limb �������������������������������������������������� 163 14.3.3 Influence of Photobiomodulation Therapy on Diabetic Peripheral Neuropathy�������������������������������������� 165 Appendix A: Michigan Neuropathy Screening Instrument (Part A)�������������������� 167 Appendix A: Michigan Neuropathy Screening Instrument (Part B)�������������������� 169 Appendix B: Douleur Neuropathique 4 Questions (DN4)���������������������������������� 171 Appendix C: Neuropathy Symptoms Score (NSS)���������������������������������������������� 173 Appendix D: The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) Pain Scale���������������������������������������������������������������������� 175

About the Authors

Animesh  Hazari  (MS.  Clinical Biomechanics, Ph.D.) graduated from Robert Gordon University, Scotland, UK, and completed his Ph.D. on the Diabetic Foot at Manipal Academy of Higher Education, MAHE, Manipal, India. Currently, he is working as an Assistant Professor and Head of Department, LSPPS at Lovely Professional University, Jalandhar, Punjab, India. He is a well-known researcher with more than 20 publications in peer-reviewed, indexed national and international journals and received Best Researcher awards for three consecutive years (2018–2020). He has also served as the Joint Secretary for Manipal University Research Forum to promote and organize quality research activities. His research interests include the diabetic foot, diabetes peripheral neuropathy, clinical biomechanics, sports biomechanics, and neuromuscular conditions. G. Arun Maiya  is presently working as the Dean at Manipal College of Health Professionals (MCHP) and as a Professor and Chief of the Center for Diabetic Foot Care and Research, Manipal, India. He is a certified clinical podiatry specialist and accredited foot balance medical expert with the Finland Podiatry Medical Association, and a member of both the American Podiatry Medical Association and Indian Podiatry Association. He has published more than 120 scientific publications in both national and international journals. His main areas of expertise include the clinical evaluation of the diabetic foot, biomechanical assessment of the foot, and photobiomodulation.

xvii

List of Figures

Fig. 1.1 Diabetic foot ulcer classified as Grade I as per Wagner’s system. (Source: Diabetic Foot Centre, KH, Manipal, India)����������������������������  3 Fig. 1.2 Diabetic foot ulcer classified as Grade II as per Wagner’s system. (Source: Diabetic Foot Centre, KH, Manipal, India)����������������������������  3 Fig. 1.3 Diabetic foot ulcer classified as Grade III as per Wagner’s system. (Source: Diabetic Foot Centre, KH, Manipal, India)����������������������������  4 Fig. 1.4 Diabetic foot ulcer classified as Grade IV as per Wagner’s system. (Source: Indian Podiatry Association)��������������������������������������������������  5 Fig. 1.5 Diabetic foot ulcer classified as Grade V as per Wagner’s system. (Source: Indian Podiatry Association)��������������������������������������������������  6 Fig. 1.6 Diabetic foot ulcer classified as Stage D, Grade III, and II as per Armstrong system. (Source: Indian Podiatry Association, India)��������  7 Fig. 1.7 Nueroischemic ulcer. (Source: Diabetic Foot Centre, KH, Manipal, India)������������������������������������������������������������������������������ 10 Fig. 2.1 National and global prevalence of diabetes mellitus (8th edition, IDF Atlas 2017)���������������������������������������������������������������� 15 Fig. 2.2 Prevalence of various foot complications (DFS) in T2DM from our study at KMC, Manipal, Karnataka, India������������ 19 Fig. 3.1 Flowchart for etiological pathway for diabetes peripheral neuropathy. (Rosyid 2017)�������������������������������������������������� 24 Fig. 3.2 Flowchart depicting etiopathological pathway for diabetic foot syndrome (DFS) �������������������������������������������������������� 25 Fig. 3.3 (a) Normal vascular mechanism. (b) Altered vascular mechanism in diabetic foot syndrome (DFS) �������������������������������������� 28 Fig. 4.1 Economic burdens of diabetes mellitus (8th edition, IDF Atlas 2017)������������������������������������������������������������������������������������ 35 Fig. 5.1 (a) 10 g Monofilament test. (b) VPT testing. (c) Monofilament testing sites�������������������������������������������������������������� 41 Fig. 5.2 Discoloration of skin in diabetic foot syndrome. (Source: Indian Podiatry Association) ������������������������������������������������ 46 Fig. 6.1 Diabetic foot syndrome—a clinical triad���������������������������������������������� 50 Fig. 6.2 Dryness of skin and diabetic dermopathy in diabetes mellitus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)���������������������������������������� 52 xix

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List of Figures

Fig. 6.3 Plantar fissures in diabetes mellitus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)�������������������� 52 Fig. 6.4 Nail bed infection in diabetes mellitus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)�������������������� 52 Fig. 6.5 Claw toes in diabetes mellitus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)�������������������� 53 Fig. 6.6 Showing hallux valgus angle in diabetes mellitus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)������������������������������������������������������������������ 54 Fig. 6.7 Showing hallux rigidus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)�������������������� 54 Fig. 6.8 Showing Charcot foot in diabetes mellitus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)������������������������������������������������������������������ 55 Fig. 6.9 Callus and corn formation in diabetes mellitus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)������������������������������������������������������������������ 57 Fig. 6.10 Diabetic foot ulcer in diabetes mellitus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)������������������������������������������������������������������ 57 Fig. 6.11 Showing amputation in diabetes mellitus. (Source: Centre for Diabetic Foot Care, KH, Manipal, Karnataka, India)������������������������������������������������������������������ 57 Fig. 7.1 (a) Ulcer on right heel. (b) Ulcer on left heel �������������������������������������� 60 Fig. 7.2 Diabetic foot ulcer on second metatarsal head ������������������������������������ 61 Fig. 7.3 Diabetic foot ulcer on the right metatarsal head (4th–5th toe) ������������ 62 Fig. 7.4 Diabetic foot ulcer on the fifth metatarsal head������������������������������������ 63 Fig. 8.1 Closed kinematic-kinetic chain analysis���������������������������������������������� 68 Fig. 8.2 Formation and breakdown of callus in diabetic foot syndrome. (Adapted from the practical guidelines on the management and prevention of the diabetic foot, 1999)������������ 69 Fig. 8.3 Diagrammatic representation for the calculation of MLA height using Chippaux-­Smirak Index ������������������������������������ 71 Fig. 11.1 Normal presentations of foot arches ���������������������������������������������������� 88 Fig. 11.2 A stone in the footwear of a DPN patient. (Source: Indian Podiatry Association)�������������������������������������������������� 90 Fig. 11.3 Isokinetic testing at ABTP, Mohali ������������������������������������������������������ 91 Fig. 11.4 Motion analysis at ABTP, Mohali�������������������������������������������������������� 92 Fig. 11.5 Balance and coordination testing at ABTP, Mohali������������������������������ 93 Fig. 11.6 Postural analysis at ABTP, Mohali������������������������������������������������������� 94 Fig. 12.1 Important spatiotemporal gait variables���������������������������������������������� 103

List of Figures

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Fig. 12.2 Placement of markers for kinematic gait analysis������������������������������ 109 Fig. 12.3 Isopressure view—comparison of static plantar pressure distribution between Non-­diabetes (left) and Type 2 DM with DPN (right) ������������������������������������������������������ 118 Fig. 12.4 Forefoot, hindfoot rotation using center of pressure in plantar pressure analysis ���������������������������������������������������������������� 119 Fig. 12.5 Foot rotation profile and comparison of right–left plantar pressure analysis for Type 2 DM with DPN �������������������������� 120 Fig. 12.6 Lateral-medial average pressure ratio at left and right foot in Type 2 DM with DPN���������������������������������������������� 121 Fig. 12.7 Lateral-medial maximum force ratio at left and right foot in Type 2 DM with DPN. Note: Please note that in all Type 2 DM with DPN, the lateral/medial analysis ratio was greater than 1 �������������������������������������������������������� 122 Fig. 12.8 Impulsive force (pressure × time) for Type 2 DM with DPN ������������ 123 Fig. 12.9 Contact time for Type 2 DM with DPN (dark blueprint suggests more time) �������������������������������������������������� 124

List of Tables

Table 1.1 Table 1.2 Table 1.3 Table 2.1 Table 5.1 Table 7.1 Table 7.2 Table 7.3 Table 7.4 Table 7.5 Table 8.1 Table 8.2 Table 8.3 Table 8.4 Table 9.1 Table 9.2 Table 9.3 Table 9.4 Table 9.5 Table 9.6 Table 9.7 Table 11.1 Table 12.1

DFS classification suggested by Wagner��������������������������������������������  3 DFS classification given by Armstrong����������������������������������������������  6 DFS classification given by SINDBAD ��������������������������������������������  9 Painful and non-painful neuropathy symptoms seen as DFS among T2DM���������������������������������������������������������������� 19 Common diabetes peripheral neuropathy screening methods used in clinical practice�������������������������������������������������������� 45 Demographics and sugar profile�������������������������������������������������������� 60 Anthropometric data�������������������������������������������������������������������������� 61 Diabetic foot assessment�������������������������������������������������������������������� 61 Demographic details of the patient���������������������������������������������������� 62 Ulcer/wound assessment�������������������������������������������������������������������� 62 Functional foot classification based on general guidelines given by Shavelson (2011) ���������������������������������������������������������������� 72 Functional foot classification based on postural sequellae given by Shavelson (2011) ���������������������������������������������������������������� 72 Functional foot classification based on characteristic lesion patterns given by Shavelson (2011) ���������������������������������������� 72 Functional foot classification based on shoe wear characteristic given by Shavelson (2011)���������������������������������� 72 Clinical characteristics ���������������������������������������������������������������������� 77 Musculoskeletal characteristics���������������������������������������������������������� 78 Biomechanical characteristics in open and closed chain�������������������� 79 Mean kinetics at foot in type 2 diabetes mellitus and peripheral neuropathy������������������������������������������������������������������ 80 Mean kinematics at ankle joint in type 2 diabetes mellitus and peripheral neuropathy ���������������������������������������������������������������� 80 Mean kinematics at knee joint in type 2 diabetes mellitus and peripheral neuropathy������������������������������������������������������������������ 80 Gait characteristics ���������������������������������������������������������������������������� 81 List of common outcome measures and tools used for kinematic analysis in diabetes mellitus population���������������������� 94 Demographic data of compared groups�������������������������������������������� 102

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List of Tables

Table 12.2 Differences in spatiotemporal parameters of gait between the groups��������������������������������������������������������������  104 Table 12.3 Comparison of kinematics parameters between DPN, NDPN, and NDM ������������������������������������������������������������������ 107 Table 12.4 Comparison of kinetic variables between DPN, NDPN, and NDM ���������������������������������������������������������������������������� 117 Table 12.5 Comparison of plantar pressure distribution pattern between DPN, NDPN, and NDM���������������������������������������������������� 118 Table 12.6 Musculoskeletal strength among Type 2 DM with DPN, Type 2 DM without DPN, and non-diabetes mellitus���������������������������������������������������������������� 126 Table 12.7 Muscle length findings among Type 2 DM with DPN, Type 2 DM without DPN, and non-diabetes mellitus���������������������� 128 Table 12.8 Vascular findings among Type 2 DM with DPN, Type 2 DM without DPN, and non-­diabetes mellitus���������������������� 130

1

Introduction and Understanding of the Diabetic Foot Syndrome

Foot is an essential body part for efficient weight distribution and locomotion. Foot complications are very commonly seen but often ignored by people with diabetes mellitus until recent past where “diabetic foot syndrome” (DFS) has become a serious concern. It is now well accepted that DFS has a serious impact on the morbidity and mortality of diabetes mellitus population leading to multiple foot complications. Among all, foot ulceration is the most dangerous which leads to amputation frequently. The data from the Netherland, reported by Bakker et  al. (2005), confirmed that a lower limb was lost every 30 s among diabetes mellitus population. As per the recent trends, the number has increased drastically across the globe, and Indians may have suffered to the highest extent due to lack of awareness, management resources, and economic constraints. Before we go into much detail, let us try to understand the term “diabetic foot syndrome.” All complications of the foot due to diabetes were previously described under the umbrella of “Diabetic Foot.” In the recent past, the term “diabetic foot” has been replaced with “diabetic foot syndrome.” The “diabetic foot syndrome” as defined by the World Health Organization is an “ulceration of the foot (distally from the ankle and including the ankle) associated with neuropathy and different grades of ischemia and infection” (Tuttolomondo et al. 2015). In other words, diabetic foot syndrome could be considered as a clinical triad of neurological, vascular, and musculoskeletal changes in the foot of a diabetes mellitus individual. In this book, we shall refer diabetic foot syndrome to any complications, deformity, or spectrum of disorders in the foot of diabetes mellitus people unless stated otherwise. Thus, DFS consists of all possible changes in the foot of diabetic population. It has been found that there is a foot lesion associated out of every four diabetes mellitus individual worldwide, which suggests that diabetic foot syndrome is relatively very common and should be addressed well. Among the most common clinical presentation of diabetic foot syndrome, diabetes peripheral neuropathy accounts for the highest. Many studies have reported that diabetes peripheral neuropathy (DPN) is one the most serious complications of

© Springer Nature Singapore Pte Ltd. 2020 A. Hazari, G. A. Maiya, Clinical Biomechanics and its Implications on Diabetic Foot, https://doi.org/10.1007/978-981-15-3681-6_1

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1  Introduction and Understanding of the Diabetic Foot Syndrome

diabetes that accounts for significant morbidity in terms of foot ulceration and amputation (Sawacha et al. 2012). DPN refers to the presentation of sign and symptoms for peripheral neuropathy among people with diabetes mellitus when other causes for neuropathy have been excluded. Among all types of DPN, 75% present with symmetrical distal neuropathy. We shall discuss DPN in more detail in the upcoming chapters. Apart from neuropathy, the vascular changes consist of a complex interaction between inflammatory, metabolic, and procoagulant variables. The vascular complications also have a close relationship with insulin resistance, obesity, hypertension which creates an adipo-vascular axis predisposing to the higher risk of diabetic foot syndrome. Thus peripheral artery disease could be seen due to direct damage to the nerves and blood vessels. The diabetic vascular disease has three main components like arteritis, neuropathy, and large vessel atherosclerosis. Although the neuropathy and vascular mechanism of DFS are well documented, the role of musculoskeletal and biomechanical alteration cannot be ignored. It has been seen that lower levels of plasma adiponectin and higher interleukin-6 lead to musculoskeletal foot changes, thus causing foot ulceration. If not treated well, it may progress to gangrene and require amputation. It is evident that a diabetic foot syndrome could have multiple presentations depending upon the pathogenic pathway consisting of neuropathy, vascular, autonomic, musculoskeletal, and biomechanical changes. Thus to understand the presentation of a diabetic foot syndrome, an established classification system could be beneficial which has been discussed below.

1.1

Classification of Diabetic Foot

The presentation and outcomes of a diabetic foot syndrome are diverse, thus many classifications prevail. The most widely used classification includes Wagner’s, University of Texas (Armstrong), PEDIS, and SINDBAD. All these classifications have provided a better understanding of diabetic foot syndrome. These classification systems are easily accessible for academic purpose, and we shall discuss about each briefly here.

1.1.1 Wagner’s Classification The Wagner’s classification of diabetic foot was introduced by Wagner in 1981 for clinical description, diagnosis, and treatment of diabetic foot syndrome. It was validated by Smith (2003). It basically grades the diabetic foot ulcers ranging from Grade 0 to Grade V where Grade I, II, and III are non-gangrenous and Grade IV and V are gangrenous as shown in Table 1.1. According to Wagner Grade I classification, localized and superficial ulcer may be present and could be treated by antibiotics and glycemic control. An example of such diabetic foot syndrome can be seen in Fig. 1.1. Similarly, Fig. 1.2 depicts Grade II, Fig. 1.3 Grade III, Fig. 1.4 Grade IV, and Fig. 1.5 Grade V as per the classification system given by Wagner.

1.1  Classification of Diabetic Foot

3

Table 1.1  DFS classification suggested by Wagner Grade 0 Grade I Grade II Grade III Grade IV Grade V

Foot at risk Localized, superficial ulcer Deep ulcer to bone, ligament, or joint Deep abscess, osteomyelitis Gangrene of toes, forefoot Gangrene of entire foot

Fig. 1.1  Diabetic foot ulcer classified as Grade I as per Wagner’s system. (Source: Diabetic Foot Centre, KH, Manipal, India)

Fig. 1.2  Diabetic foot ulcer classified as Grade II as per Wagner’s system. (Source: Diabetic Foot Centre, KH, Manipal, India)

Prevention Antibiotics and glycemic control Debridement, antibiotics, and glycemic control Debridement, some form of amputation Wide debridement and amputation Below knee amputation

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1  Introduction and Understanding of the Diabetic Foot Syndrome

Fig. 1.3  Diabetic foot ulcer classified as Grade III as per Wagner’s system. (Source: Diabetic Foot Centre, KH, Manipal, India)

The classification given by Wagner could be very useful in identifying the gangrenous nature of diabetic foot along with possible treatment approaches. However, it does not identify the extent of infection and ischemia (Oyibo et al. 2001). Thus, further classification was required.

1.1.2 University of Texas (Armstrong) The University of Texas classification of diabetic foot ulcer was given in 1996 (Lavery et  al. 1996) and validated by Armstrong and his colleagues in 1998 (Armstrong et al. 1998). The classification has four stages (Stage A, B, C, and D) with grade ranging from 0 to III. This classification could be helpful in determining the outcome with specific features on the depth, infection, and ischemia for risk of amputation in diabetic foot as shown in Table 1.2. The diabetic foot ulcers shown in Fig. 1.6 could be better classified by grading given by Armstrong in comparison to Wagner as infection, and greater extent of ischemia can be seen.

1.1.3 PEDIS Classification of Diabetic Foot This classification system was introduced by the International Working group of the Diabetic Foot (IWGDF) in 2003 (Gandhi et  al. 2019; Schaper et  al. 2003). The PEDIS classification stands for Perfusion, Extent/Size, Depth/Tissue Loss, Infection and Sensation. The grading system is based on scientific literature and expert opinion to identify the severity of diabetic foot syndrome. It could be more user friendly, objective, and applicable to research. A PEDIS score of 7.5 can predict the outcome

1.1  Classification of Diabetic Foot

5

Fig. 1.4  Diabetic foot ulcer classified as Grade IV as per Wagner’s system. (Source: Indian Podiatry Association)

of diabetic foot ulcer with 100% sensitivity (Gandhi et al. 2019). The details on the classification criteria of PEDIS could be seen explained as below:

1.1.3.1 Perfusion Grade I—No signs or symptoms of peripheral artery disease (PAD) in the affected foot, in combination with: • Palpable dorsalis pedal or posterior tibial artery or • Ankle brachial index 0.9–1.1 or • Toe brachial index >0.6 or • Transcutaneous oxygen pressure (TcPO2) >60 mmHg

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1  Introduction and Understanding of the Diabetic Foot Syndrome

Fig. 1.5  Diabetic foot ulcer classified as Grade V as per Wagner’s system. (Source: Indian Podiatry Association)

Table 1.2  DFS classification given by Armstrong Stage Grade 0 A Pre- or post-ulcerative lesion completely epithelialized B Infection C Ischemia D Infection and ischemia

Grade I Superficial ulcer, not involving tendon capsule or bone Infection Ischemia Infection and ischemia

Grade II Ulcer penetrating to tendon or capsule Infection Ischemia Infection and ischemia

Grade III Ulcer penetrating to bone or joint Infection Ischemia Infection and ischemia

1.1  Classification of Diabetic Foot

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Fig. 1.6  Diabetic foot ulcer classified as Stage D, Grade III, and II as per Armstrong system. (Source: Indian Podiatry Association, India)

Grade II—Presence of signs and symptoms of PAD, but not of critical limb ischemia (CLI). • • • • •

Presence of intermittent claudication Ankle brachial index 50 mmHg or Toe brachial index 30 mmHg or TcPO2 30–60 mmHg or Other abnormalities on noninvasive testing, compatible with PAD but not with CLI Grade III—Critical limb ischemia, as defined by:

• Systolic ankle blood pressure 38 or 90 beats/min Respiratory rate >20 breaths/min PaCO2 12,000 or 130 mg/dL, hypertriglyceridemia, and microalbuminuria could be seen among patients with diabetic foot ulcers which ultimately increase the risk for morbidities and mortality. The mortality rate for DFS ranges from 10 to 24% (Chammas et al. 2016). It is also reported that people with diabetic foot ulcers have lower survival rate by 5 years compared to non-ulcerated diabetes mellitus patients.

4.6

Painful Neuropathy

Painful diabetic peripheral neuropathy (pDPN) is a serious concern that demands proper attention and management. It is defined as pain arising from direct consequences of abnormalities within the somatosensory system among individuals with diabetes mellitus. Studies have reported that 50% of people with long-term diabetes have DPN and 50% of them suffer from painful symptoms called “painful diabetes neuropathy.” It can be diagnosed with classical signs and symptoms of neuroischemic pain. Associated pain has been clinically described as tingling, numbness, sensitive to touch, burning, electrical, stabbing, shock-like feeling, paresthesia, hypoesthesia, and allodynia. It could be associated with diurnal variation and thus found to be increased typically at night. Pain may start at both feet initially and progress to involve calves, hands, and fingers. Studies have also reported that the pain in DPN is often excruciating but may revert spontaneously. A number of studies have highlighted the impact of neuropathic pain on quality of life in type 2 diabetes mellitus patients. It can affect the entire personality of an individual. A study reported that all areas of life including mood, sleep, independence, self-worth, work skills, and interpersonal relationship could be easily disturbed. A study done in the Republic of Croatia provided valuable information on the impact on quality of life among patients with painful diabetic neuropathy (Dobrota et al. 2014). The study concluded that sleeping disorders, problems in micturition, and defecation were higher in patients with painful neuropathy. A recent study found that the presence of pDPN was associated with quality of life where the highest impact was seen at physical and mental health domains (Degu et  al. 2019). Similarly, another study concluded that the presence of pDPN is closely associated with greater comorbidities in terms of limb infection. Tenfold greater limb amputation and higher healthcare service cost were reported in patients with painful neuropathy compared to non-painful DPN. Some authors have also suggested that the health-­related QoL in painful peripheral neuropathy gets significantly affected. Similar to the study done previously which reported significant lower scores in five out of the six domains that

References

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consisted of energy, sleep, pain, physical mobility, and emotional stress, Fejfarová et al. (2014) reported significant impact on the psychological and social characteristics. There has been a strong relationship between pain intensity and worsening of self-assessed health status. Thus, it could be said that from a patient’s perspective, DFS is a serious concern that requires proper attention and care. Summary: From the patient’s perspective, the quality of life against the DFS is very poor as it affects their life in all domains. Patients concern for pain, discomfort, economic burden and fear of amputation makes DFS a serious concern in the Indian society.

References Al-Rubeaan K, Al Derwish M, Ouizi S, Youssef AM, Subhani SN, Ibrahim HM, Alamri BN (2015) Diabetic foot complications and their risk factors from a large retrospective cohort study. PLoS One 10(5):e0124446 Atlas ID (2015) International Diabetes Federation, Brussels Atlas ID (2017) International Diabetes Federation, Brussels, Belgium; 2013. International Diabetes Federation (IDF) Chammas NK, Hill RLR, Edmonds ME (2016) Increased mortality in diabetic foot ulcer patients: the significance of ulcer type. J Diabetes Res 2016:2879809 Degu H, Wondimagegnehu A, Yifru YM, Belachew A (2019) Is health related quality of life influenced by diabetic neuropathic pain among type II diabetes mellitus patients in Ethiopia? PLoS One 14(2):e0211449 Dobrota VD, Hrabac P, Skegro D, Smiljanic R, Dobrota S, Prkacin I, Brkljacic N, Peros K, Tomic M, Lukinovic-Skudar V, Kes VB (2014) The impact of neuropathic pain and other comorbidities on the quality of life in patients with diabetes. Health Qual Life Outcomes 12(1):171 Fejfarová V, Jirkovská A, Dragomirecká E, Game F, Bém R, Dubský M, Wosková V, Křížová M, Skibová J, Wu S (2014) Does the diabetic foot have a significant impact on selected psychological or social characteristics of patients with diabetes mellitus? J Diabetes Res 2014:371938 Kerr M, Rayman G, Jeffcoate WJ (2014) Cost of diabetic foot disease to the National Health Service in England. Diabet Med 31(12):1498–1504 Shahi SK, Kumar A, Kumar S, Singh SK (2012) Prevalence of diabetic foot ulcer and associated risk factors in diabetic patients from North India. Age 47(8):55–26 Singh N, Armstrong DG, Lipsky BA (2005) Preventing foot ulcers in patients with diabetes. JAMA 293(2):217–228 Sriyani KA, Wasalathanthri S, Hettiarachchi P, Prathapan S (2013) Predictors of diabetic foot and leg ulcers in a developing country with a rapid increase in the prevalence of diabetes mellitus. PLoS One 8(11):e80856 Vileikyte L, Leventhal H, Gonzalez JS, Peyrot M, Rubin RR, Ulbrecht JS, Garrow A, Waterman C, Cavanagh PR, Boulton AJ (2005) Diabetic peripheral neuropathy and depressive symptoms: the association revisited. Diabetes Care 28(10):2378–2383

5

Clinician’s Perspective on Diabetic Foot Syndrome

From a clinician’s perspective, a diabetic foot can be very challenging to assess and manage. Since the course of the diseases is progressive, early screening and assessment could be the key to successful management.  This chapter has been written under the  guidance from  our clinical expert in diabetes mellitus Dr. Shaivashankara K.N (Unit Head, Kasturba Hospital, Manipal) who has put his vast experiences in assessing and managing over 1,000  patients. A variety of clinical tests are suggested for establishing the presence of  T2DM, DPN, and DFS.  The most common clinical biochemistry and assessment techniques have been mentioned in this book. Before we directly jump onto the clinical aspects of a diabetic foot syndrome, it would be important to know the most common diagnostic tests for the presence of type 2 diabetes mellitus.

5.1

Diagnostic Criteria for Type 2 DM

A number of biochemical tests are available for establishing the presence of type 2 diabetes mellitus. An individual could be confirmed to have diabetes mellitus if one or more of the criteria are met.

5.1.1 Fasting Blood Sugar Level (FBS) This is the most commonly used test where a blood sample is collected over an overnight fasting period. The normative values may differ from races to country and particular habitat. As per the latest data suggested by American Diabetes Association and IDF Atlas 2017, a fasting plasma glucose ≥7 mmol/L or equivalent of 126 mg/ dL could be considered as diagnostic criteria for  T2DM (ADA 2014; ADA 2015; ADA 2017). However, in India, a value of ≥110 mg/dL has been reported by

© Springer Nature Singapore Pte Ltd. 2020 A. Hazari, G. A. Maiya, Clinical Biomechanics and its Implications on Diabetic Foot, https://doi.org/10.1007/978-981-15-3681-6_5

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5  Clinician’s Perspective on Diabetic Foot Syndrome

many clinicians and researchers for considering the clinical presence of diabetes mellitus.

5.1.2 Postprandial Blood Sugar Level (PPBS) This test is done after 2 h following a load of 75 g oral glucose. This test is highly sensitive and a value ≥11.1 mmol/L or 200 mg/dL could be taken as a confirmatory test for the presence of T2DM (ADA 2014; ADA 2015; ADA 2017).

5.1.3 Random Blood Sugar Level (RBS) For a clinical use, an RBS value could be very useful where FBS and PPBS cannot be assessed. Clinicians prefer RBS in community camps as screening test. This could help to save time and effort for an efficient diagnostic measure among diabetes mellitus population. A random blood sugar level ≥200 mg/dL could be suggestive of diabetes mellitus (ADA 2014; ADA 2015; ADA 2017).

5.1.4 Glycated Hemoglobin (HbA1c) This test has been found to the most sensitive and accurate for the clinical diagnosis of diabetes mellitus. A value ≥48 mmol/L or an equivalent of 6.5 expressed in percentage should be considered as the most significant diagnostic criteria (ADA 2017).

5.2

Screening for Diabetic Foot Syndrome

Since DFS is a clinical manifestation having a combined presentation of neuropathy, vascular, and musculoskeletal changes, the diagnostic criteria for DFS is mostly confirmed through clinical assessment and examination. In this book, we have gathered the information available at various resources into one for easy understanding using the most recent clinical tools available. From a clinician perspective of a diabetic foot, a detailed assessment would be essential to understand the nature and course of the disease. Based on the assessment and examination, effective treatment protocols could be developed for effective management. In clinical practice, the order of assessment includes neurological, dermatological (autonomic), vascular, musculoskeletal, and biomechanical.

5.3

Diabetes Peripheral Neuropathy Assessment

The assessment under these sections is subdivided into (a) sensory, (b) motor, and (c) autonomic evaluation.

5.3  Diabetes Peripheral Neuropathy Assessment

a

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b

c

Fig. 5.1 (a) 10 g Monofilament test. (b) VPT testing. (c) Monofilament testing sites

5.3.1 Sensory Neuropathy Assessment (a) It consists of testing for protective sensation in feet and lower limb. For example, light touch using cotton, temperature (hot/cold) using the palpatory method, infrared temperature gun device for the local temperature at dorsum and plantar aspect of feet. The protective sensation testing is performed using the standard procedure for 5.07/10 g Semmes Weinstein Monofilament Test and vibration sense testing using biothesiometer (vibration pressure threshold device/VPT) as shown in Fig. 5.1a, b, respectively. In a normal routine clinical practice, six sites are tested as shown in Fig. 5.1c. A correct response within 5 s is considered as normal, correct response for ≥10 s is marked as altered/delayed, and the absent or wrong response is marked absent. The use of vibration sense with biothesiometer is an important objective tool to detect the presence of sensory peripheral neuropathy among type 2 diabetes mellitus participants. A value of 1–14 V is reported as the absence of neuropathy, 14–20  V as a risk for neuropathy and values above 20  V is considered as neuropathy among Indian population based on previous literature (Ghosal et al. 2012). Though studies report that it is difficult to determine the severity of

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neuropathy based on vibration pressure threshold (VPT) values and give a cut-­ off for grading the neuropathy severity, our clinical experience has been used to classify neuropathy as mild, moderate, and severe. This classification has been based on the correlation of other neuropathy signs and symptoms with VPT score on a larger patient population. The value of 20–24.9 V is considered as mild neuropathy, 25–39.9  V as moderate neuropathy, and >40  V as severe neuropathy. The maximum value is set at 50  V by default which could be a drawback of the device. Since the loss of sensation in diabetic neuropathy could progress far beyond the maximum VPT of the biothesiometer, values of vibration perception should be measured over a wide range with Maxivibrometer (Van Deursen et al. 2001).

5.3.2 Motor Neuropathy (b) The motor neuropathy is confirmed by testing the strength of proximal and distal muscle of foot and lower limb. The muscles tested and the procedure for testing have been explained in the subsequent section under musculoskeletal assessment. Ankle jerk is also tested, and its absence could be suggestive of peripheral neuropathy (Shehab et al. 2011).

5.3.3 Autonomic Neuropathy (c) The presence of autonomic neuropathy is confirmed with loss of sweating and dry skin in the foot and lower extremity, discoloration of feet, change in the skin texture of plantar and dorsum aspect of foot, and presence of deep fissures. The presence of deep fissure should be carefully reported as clinical signs of peripheral neuropathy among Indians as it could be closely associated with occupation and climatic conditions. In India, people often walk barefoot at home and in agricultural fields which could be a source of deep fissures.

5.3.4 Neuropathy Scales and Screening Tools Few commonly used neuropathy scales and tools are (1) Michigan Neuropathy Screening Instrument (MNSI), (2) The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) Pain Scale, (3) Douleur Neuropathique 4 Questions (DN4) Neuropathic Pain Diagnostic Questionnaire, (4) Neuropathic Disability Score (NDS), and (5) Neuropathy Symptom Score (NSS). These documents are freely available online for use under academic and research purposes. For the reader reference, a copy has also been attached in the appendix section: 1. MNSI: It is a commonly used tool for screening DPN and consists of two components, viz. “A” is a self-administered questionnaire and component “B” is an

5.3  Diabetes Peripheral Neuropathy Assessment

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examination performed by the clinicians. Studies have reported a good specificity and sensitivity using second components. A study done by Moqhtaderi, Bakshipour, and Rashidi (2006) reported that score of 1.5, 2, 2.5, and 3 as cut-off values in the second component (Part B) of MNSI had a sensitivity of 79%, 65%, 50%, and 35%, whereas the specificity was 65%, 83%, 91%, and 94%, respectively. In regards to our clinical experience, we suggest a score of ≥7 in the first component and ≥2.5/10 in the second component which could be used as cut-off value in clinical practice within India. 2. LANSS: It is a neuropathy pain assessment tool. It is also a very effective clinical tool having two components (A—pain questionnaire and B—sensory testing). Previous studies have suggested reliability of 0.735 using Cronbach’s α coefficients with a specificity and sensitivity of 58% and 97.1%, respectively. A total score of ≥12/24 could be considered as a neuropathic mechanism causing neuropathy pain. 3. DN4: It is a neuropathic pain assessment questionnaire which has just four questions and thus time efficient. A score of ≥4/10 has ˃90% specificity for neuropathy pain mechanism. 4. NDS (Revised Version): The original NDS consists of 35 items on both sides of the foot. Since it is time consuming and difficult to use in clinical practice, neuropathy impairment score (NIS-LL) was developed based on NDS having 14 items. However, NIS-LL had more emphasis on motor aspects. Therefore, a revised version of NDS was developed to use in clinical practice (Yang et  al. 2014). The  revised NDS could be used to stratify the severity of neuropathy based on the score. It has a maximum score of 10 with testing components like 128  Hz tuning fork, neurotip, hot/cold, and ankle reflex in the bilateral foot. Score 0  is given for the present response, whereas 1  is allocated for absent response to first three components. For ankle reflex, 1 is given for reduced jerk reflex, and 2 for absent reflex. As per the scoring system, a score of 3–4  is considered as mild neuropathy, 5–6 as moderate neuropathy, and 7–10 as severe neuropathy. 5. NSS: This scale could be used to distinguish the signs and symptoms of neuropathy with vascular deficits. The maximum score is 9 for each limb. A score of 3–9 signifies neuropathy and 0–3 suggests vascular changes.

5.3.5 Nerve Conduction Velocity The nerve conduction velocity (NCV) test very commonly found in studies as “NCS” could be a very useful noninvasive, objective measure for the prediction and presence of diabetes peripheral neuropathy. It has been commonly reported that people with DPN show  a significant  decrease in nerve velocity during NCV test considering the fact that DPN causing demyelination of large fibers and thereby producing lower action potential. Recent evidence from a study conducted in 2018 by Tehrani (2018) suggested an abnormal NCV among people with DPN conducted over a total of 77 patients (48 women and 29 men). The most commonly tested

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5  Clinician’s Perspective on Diabetic Foot Syndrome

nerves are ulnar motor nerve of ankle and knee, peroneal motor nerve of knee, and the sural sensory nerve. Also some researchers hypothesize that NCS could be used for early detection of DPN. Jin and Park (2015) studied 59 T1DM at baseline where nerve conduction velocity and amplitude were significantly reduced without clinical signs of neuropathy. However, in a follow-up of 13  years, nine patients (15%) showed clinical neuropathy, suggesting that NCS could be a very early indicator of DPN. It should also be noted that the study was conducted on T1DM, and the result could be more significant in T2DM.

5.3.6 Electromyography The motor recruitment frequency and pattern are commonly assessed using electromyography (EMG). Multiple studies have been performed to understand the motor pattern in DPN. EMG is an electrophysiological techniques used apart from NCV for early prediction of DPN particularly successful in subclinical cases. The most significant change in EMG among DPN is abnormal peak potentials, reduction in motor recruitment, and altered motor firing leading to evident signs of motor neuropathy. Surface and needle electrodes could be used, but for DPN needle electrodes are usually avoided. Thus we find that NCV and EMG are important DPN screening tool, but due to its high cost, the use in clinical practice is limited. Table  5.1 identifies the most common DPN screening methods and tools used by various researchers in clinical studies.

5.4

Vascular Assessment

Vascular assessment and examination determine changes in the microvascular and macrovascular structure and function. Pedal pulse characteristics are checked for tibialis posterior artery and dorsalis pedes artery. Ankle-brachial index (ABI) test is done to determine arterial insufficiency. A value of 0.9–1.2 is considered as normal. Test for the peripheral venous disease could also be performed. Doppler test or angiography could be clinically most useful to determine the blood flow in the lower limb.

5.5

Dermatological Assessment

This assessment includes observational findings like deep plantar fissures, changes in skin color, etc. The dermatological changes due to diabetic foot syndrome are termed as diabetic dermopathy. The blackish discoloration of feet with a venous ulcer could be the common manifestation seen in a diabetic foot as shown in Fig. 5.2.

5.6  Musculoskeletal Assessment

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Table 5.1  Common diabetes peripheral neuropathy screening methods used in clinical practice Author and year Neuropathy screening methods and tools Fortaleza 2014 1. Semmes–Weinstein 10 g monofilaments 2. Michigan neuropathy screening instrument (score ≥ 8) Raspovic 2013 Vibration perception threshold (VPT) >25 V in combination with a positive neuropathy deficit score (NDS) Formosa 2013 Semmes–Weinstein 10 g monofilament (neuropathy considered if one or more out of five sites were insensate) Melai 2011 Standardized neurological examination Gomes 2011 Michigan neuropathy screening instrument >3/15 (questionnaire) and score of >4/10 (examination) Rao 2010 5.07 Semmes–Weinstein monofilament and vibration perception threshold of 25 V or higher Saura 2010 10 g monofilament and tuning fork of 128 Hz according to the Michigan protocol Bacarin 2009 1. Michigan neuropathy screening instrument questionnaire (score > 6) 2. 10 g monofilament (insensitive to at least two sites) Sawacha Z 1. Michigan neuropathy screening instrument questionnaire (>3/15 2009 symptoms) 2. Ankle and patellar reflex 3. Less than 3 response for 10 sites on 10 g Semmes–Weinstein monofilament test 4. Vibration pressure threshold of >25 V 5. Pin prick using 25 mm/7 mm needle 6. 128 MHz tuning fork Savelberg 2009 Vibration perception threshold >25 V Guldemond 1. Valk scoring system for grade of polyneuropathy (score higher than 4was 2008 graded as peripheral polyneuropathy) 2. Pinprick sense and light touch sense (cotton wool) 3. Vibration using 128 Hz tuning fork 4. Ankle and knee reflex Williams 2007 5.07 Semmes–Weinstein monofilament and vibration pressure threshold >25 V Yavuz 2008 5.07 Semmes–Weinstein monofilament and a biothesiometer Yavuzer 2006 Not specified Rahman 2006 Semmes–Weinstein monofilaments ranging from 3 to 10 g Rao 2006 5.07 Semmes–Weinstein monofilaments Zimny S 2004 Vibration pressure threshold with the calibrated Rydel-Seiffer tuning fork and the Phywe Vibratester (threshold of