بیومکانیک پا و مچ پا

Cover Foot and Ankle Biomechanics Copyright List of contributors Dedication Contents Preface Anatomical Terms Used in Foot and Ankle Biomechanics 1 Anatomy of the Foot 1.1 Skeletal structures 1.1.1 Tibia and fibula 1.1.2 Segments of the foot skeleton 1.1.3 Talus 1.1.4 Calcaneus 1.1.5 Navicular 1.1.6 Cuboid 1.1.7 Medial cuneiform 1.1.8 Intermediate cuneiform 1.1.9 Lateral cuneiform 1.1.10 Metatarsals 1.1.10.1 First metatarsal 1.1.10.2 Second metatarsal 1.1.10.3 Third metatarsal 1.1.10.4 Fourth metatarsal 1.1.10.5 Fifth metatarsal 1.1.11 Phalanges 1.1.11.1 Proximal phalanges 1.1.11.2 Middle phalanges 1.1.11.3 Distal phalanges 1.2 Joints 1.2.1 Tibiofibular syndesmosis 1.2.2 Ankle joint 1.2.3 Subtalar joint 1.2.4 Talocalcaneonavicular joint 1.2.5 Calcaneocuboid joint 1.2.6 Cuboideonavicular joint 1.2.7 Cuneonavicular joints 1.2.8 Intercuneiform and cuneocuboid joints 1.2.9 Tarsometatarsal joints 1.2.10 Proximal intermetatarsal joints 1.2.11 Distal intermetatarsal joints 1.2.12 Lesser metatarsophalangeal joints 1.2.13 Hallucal metatarsophalangeal joint 1.2.14 Interphalangeal joints 1.3 Muscles and fascial specializations 1.3.1 Fascial specializations 1.3.2 Extrinsic dorsal muscles 1.3.2.1 Tibialis anterior 1.3.2.2 Extensor digitorum longus 1.3.2.3 Extensor hallucis longus 1.3.2.4 Peroneus tertius 1.3.3 Extrinsic plantar muscles 1.3.3.1 Triceps surae 1.3.3.2 Plantaris 1.3.3.3 Flexor digitorum longus 1.3.3.4 Flexor hallucis longus 1.3.3.5 Tibialis posterior 1.3.4 Extrinsic lateral muscles 1.3.4.1 Peroneus longus 1.3.4.2 Peroneus brevis 1.3.5 Intrinsic dorsal foot muscles 1.3.5.1 Extensor hallucis brevis and extensor digitorum brevis 1.3.6 Intrinsic plantar muscles 1.3.6.1 Abductor hallucis 1.3.6.2 Flexor digitorum brevis 1.3.6.3 Abductor digiti minimi 1.3.6.4 Quadratus plantae 1.3.6.5 Lumbricals 1.3.6.6 Flexor hallucis brevis 1.3.6.7 Flexor digiti minimi brevis 1.3.6.8 Adductor hallucis 1.3.6.9 Dorsal and plantar interossei 1.4 Nerves 1.4.1 The fibular nerves in the foot 1.4.2 The tibial nerves in the foot 1.5 Blood supply 1.5.1 Arteries 1.5.2 Veins 1.5.2.1 Superficial veins 1.5.2.2 Deep veins 1.5.3 Lymphatics Further reading 2 Basic Biomechanics 2.1 Introduction 2.2 Terminology 2.3 Statics 2.4 Dynamics 2.5 Strength of materials and deformation 2.6 Viscoelasticity 2.7 Summary References 3 Anatomical Nomenclature: Conundrums of Nonstandardized Foot and Ankle Terminology 3.1 Introduction 3.2 Anatomical descriptions 3.2.1 The persistence of eponyms 3.2.2 Regional descriptions 3.2.2.1 The distal element of the lower limb 3.2.2.2 Forefoot and hindfoot 3.2.3 Applying the anatomical position 3.2.4 Application specific human anatomical positions 3.2.5 Defining anatomical directions, planes, and axes 3.2.5.1 Posterior–anterior versus ventral–dorsal 3.2.5.2 Anatomical planes 3.2.5.3 Foot midline 3.3 Foot motions 3.3.1 Defining motions 3.3.1.1 Flexion-extension 3.3.1.2 Adduction-abduction versus external-internal rotation 3.3.2 Whole foot motions and their complexity 3.3.2.1 Plantarflexion-dorsiflexion 3.3.2.2 Inversion—eversion 3.3.2.3 Pronation—supination 3.4 Terminological implications of mathematical choices 3.5 Conclusion: standardizing foot and ankle terminology References 4 Kinematics and Kinetics of the Foot and Ankle during Gait 4.1 Introduction 4.2 Overview of relevant anatomy 4.3 Overview of kinematic and kinetic modeling 4.4 Healthy and impaired feet 4.5 Multisegment foot models 4.6 Future areas of research 4.6.1 Biplane fluoroscopy 4.6.2 Modeling 4.7 Conclusion References 5 Bone, Cartilage, and Joint Function 5.1 Bone components and structure 5.2 Cartilage 5.3 Joint functions 5.3.1 Talocrural joint 5.3.2 Talocalcaneal (subtalar) joint 5.3.3 Transverse tarsal joint 5.3.4 Tarsometatarsal joint 5.3.5 Metatarsophalangeal joint 5.4 Areas of future research References 6 Muscles and Tendons 6.1 Introduction 6.2 Biomechanical function 6.2.1 Normal foot 6.2.1.1 Foot stability 6.2.1.2 Balance 6.2.1.3 Locomotion 6.2.2 Aging 6.2.3 Pathologies 6.2.3.1 Plantar fasciitis 6.2.3.2 Pes planus 6.2.3.3 Toe deformities 6.2.3.4 Diabetic neuropathy 6.2.4 Footwear and orthoses 6.2.5 Interventions 6.3 Areas of future biomechanical research References 7 Ligaments 7.1 Introduction 7.2 Ligament anatomy 7.3 Mechanical properties 7.3.1 Ankle joint 7.3.1.1 Lateral collateral ligaments 7.3.1.2 Medial collateral ligaments 7.3.2 Hindfoot ligaments 7.3.2.1 Subtalar joint 7.3.2.2 Talonavicular joint 7.3.3 Midfoot ligaments 7.3.3.1 Plantar fascia 7.3.3.2 Metatarsal base ligaments 7.3.4 Forefoot 7.3.5 Variations in mechanical properties 7.3.5.1 Changes in activity level 7.3.5.2 Foot comorbidity 7.3.5.3 Age effects 7.3.5.4 Influence of anthropometric effects 7.4 Ligament sprains 7.5 Overcoming limitations 7.6 Future areas of research References 8 Plantar Soft Tissue 8.1 Introduction 8.2 Anatomy 8.2.1 Gross anatomy 8.2.2 Histological or biochemical 8.2.3 Medical imaging of tissue thickness 8.3 Biomechanical function 8.4 Mechanical properties 8.4.1 Structural in vivo testing 8.4.2 Structural ex vivo testing 8.4.3 Material ex vivo testing 8.4.4 Ultrasound 8.4.5 Other in vivo techniques 8.5 Effect of aging 8.6 Diabetic plantar soft tissue 8.6.1 Other pathologies associated with the plantar soft tissue 8.7 Areas of future biomechanical research References 9 Multisegment Foot Models 9.1 Basic principles of multisegment foot models 9.1.1 Overview of motion capture 9.1.2 Why use a multisegment foot model? 9.2 Selecting an appropriate multisegment foot model 9.2.1 Segments and bone groupings 9.2.2 Marker type and placement 9.2.3 Coordinate systems 9.2.4 Offsets 9.2.5 Standardized description of multisegment foot models 9.3 Review of current multisegment foot models 9.3.1 Milwaukee kinematic model 9.3.2 Leardini/Rizzoli kinematic model 9.3.3 Oxford kinematic model 9.3.4 MacWilliams/Kinfoot kinetic model 9.3.5 Bruening kinetic model 9.3.6 Direct comparison of current multisegment foot models 9.4 Applications, considerations, and limitations 9.4.1 Clinical applications 9.4.2 Sources of error 9.5 Areas of future biomechanical research References 10 Invasive Techniques for Studying Foot and Ankle Kinematics* 10.1 Introduction 10.2 Early invasive studies of foot and ankle biomechanics 10.3 Radiostereometric analysis 10.3.1 Technique 10.3.2 Talocrural joint 10.3.3 Relationship between the joints distal to the talus 10.3.4 Transferral of rotation between the leg and the foot 10.3.5 Ankle mortise width 10.4 Applications and significance of studies using intracortical pins for foot and ankle kinematics 10.4.1 Skin movement artifact in foot and ankle kinematics 10.4.2 Ankle kinematics 10.4.3 Foot and ankle basic research in walking and running kinematics 10.4.4 Applied studies of orthoses and shoe conditions 10.5 Limitations and future directions Appendix: Insertion of markers in bones of the foot and ankle References 11 Biplane Fluoroscopy 11.1 Introduction 11.2 Background and history of biplane fluoroscopy 11.2.1 Overview of how X-ray imaging works 11.2.2 Overview of biplane system history and evolution 11.2.2.1 Intact C-arm systems for foot bone tracking 11.2.2.2 Disarticulated C-arm systems for foot bone tracking 11.2.2.3 Custom dedicated biplane hardware for foot bone tracking 11.3 Other techniques for tracking foot bone kinematics 11.4 Challenges specific to foot and ankle tracking with biplane fluoroscopy 11.5 Overview of biplane hardware 11.6 Overview of biplane software 11.7 Clinical biplane foot and ankle studies 11.7.1 Biplane systems consisting of two C-arms 11.7.2 Biplane systems consisting of two modified C-arms 11.7.3 Biplane systems consisting of independent X-ray sources and image intensifiers 11.8 Future applications and directions References 12 Plantar Pressure and Ground Reaction Forces 12.1 Introduction: clinical relevance of force and pressure measurements in foot and ankle biomechanics 12.2 Background: force versus pressure 12.2.1 History 12.2.2 Development of measurement technologies 12.2.3 Visualization and analytical options 12.3 Research applications and selected clinical examples 12.3.1 Diabetes 12.3.2 Children’s flatfoot 12.3.3 Sports 12.4 Areas of future research References 13 Electromyography and Dynamometry for Investigating the Neuromuscular Control of the Foot and Ankle 13.1 Introduction 13.2 Electromyography 13.2.1 Surface electromyography 13.2.2 Indwelling electromyography and motor unit recordings 13.3 Dynamometry 13.3.1 Isometric 13.3.2 Dynamic 13.4 Ankle and foot related considerations and insights 13.4.1 Motor unit behavior and quantity 13.4.2 Maximal voluntary contractions and knee angle 13.4.3 History-dependence of force 13.5 Future research References 14 From Impossible to Unnoticed: Wearable Technologies and The Miniaturization of Grand Science 14.1 Introduction 14.1.1 Tech affords understanding 14.1.2 Wearable domains 14.1.3 Breakout box: what makes a successful wearable device? 14.2 The past 14.2.1 Force and pressure 14.2.2 Health and activity sensing 14.3 The present 14.3.1 Force and pressure sensing 14.3.2 Health and activity monitoring 14.3.3 Actuation and assistance 14.3.4 Haptics 14.3.4.1 Sensory substitution 14.3.4.2 Cueing and notification 14.3.5 Motion capture 14.4 The future References 15 Integrated Laboratories for Pursuing Pedal Pathologies 15.1 Introduction 15.2 Our method of approach 15.3 Integrated laboratories 15.3.1 Epidemiology 15.3.2 In vivo experimentation 15.3.2.1 Gait analysis 15.3.2.2 Plantar pressure assessments 15.3.2.3 Measures of foot structure 15.3.2.4 Other measures 15.3.3 In vitro experimentation 15.3.3.1 Histology 15.3.3.2 Cadaveric simulators 15.3.4 In silico simulation 15.3.4.1 Medical image processing 15.3.4.2 Finite element modeling 15.3.4.3 Musculoskeletal modeling 15.3.4.4 Sensitivity studies 15.3.4.5 Validation 15.4 Case study of the integrated laboratories concept to the study of hallux rigidus 15.4.1 Epidemiology 15.4.2 In vivo experimentation 15.4.3 In vitro experimentation 15.4.4 In silico simulation 15.5 Future biomechanical research References 16 Radiographs 16.1 Introduction 16.2 Radiographic technology 16.3 Standard radiographic views of the foot and ankle 16.4 Definitions of X-ray measurements of foot shape 16.5 Foot-specific applications and considerations 16.6 Clinical X-ray measures of foot shape 16.7 Issues with X-ray measures of foot shape 16.8 Areas of future biomechanical research References 17 Computed Tomography of the Foot and Ankle 17.1 Introduction 17.1.1 History and development of computed tomography 17.1.2 Comparison to other imaging modalities 17.1.3 Computed tomography protocols for the foot and ankle 17.2 Foot-specific applications and considerations 17.2.1 Disease diagnosis 17.2.2 Surgical assessment and planning 17.2.3 Biomechanics research 17.2.3.1 Kinematic measurements 17.2.3.2 Bone density properties 17.2.3.3 Computational models 17.2.3.4 Shape modeling and assessment 17.3 Areas of future biomechanical research References 18 Weight-bearing Computed Tomography of the Foot and Ankle 18.1 Introduction 18.2 Biases of conventional radiography 18.3 Technical aspects 18.4 Indications 18.5 3D biometrics 18.6 Advantages and limitations of weight-bearing computed tomography 18.7 Future areas of research 18.8 Conclusion Acknowledgments Conflict of interest statement References Further reading 19 Magnetic Resonance Imaging of the Foot and Ankle 19.1 Introduction 19.2 Magnetic resonance imaging sequences 19.3 Magnetic resonance imaging versus computed tomography 19.4 Magnetic resonance imaging appearance of musculoskeletal tissue—normal and pathology 19.4.1 Short T2 tissues 19.4.2 Tendons 19.4.3 Pseudo tendon pathology—the magic angle effect or phenomenon 19.4.4 Ligaments 19.4.5 Bone 19.4.6 Hyaline and fibrocartilaginous cartilage 19.4.7 Muscle 19.4.8 Bursa/synovia 19.5 Tailored magnetic resonance imaging protocol for the foot and ankle—indication driven 19.5.1 Imaging orientation 19.5.2 Tailored magnetic resonance imaging protocols 19.5.3 Optimized imaging planes 19.5.4 Metal artifact reduction sequences 19.6 Magnetic resonance imaging anatomy of the foot and ankle 19.6.1 Ankle 19.6.1.1 Ligaments 19.6.1.2 Bony defects and ligament injuries 19.6.2 Hindfoot 19.6.2.1 Tendons 19.6.2.2 Enthesitis—plantar fasciitis 19.6.3 Midfoot 19.6.3.1 Degenerative joint disease 19.6.3.2 Stress fractures 19.6.4 Forefoot 19.6.4.1 Morton’s neuroma 19.6.4.2 Osteomyelitis 19.6.4.3 Plantar plate tears 19.7 Areas of future research 19.7.1 Radiation-free bone imaging 19.7.2 Magnetic resonance imaging scan time reduction 19.7.3 Volumetric, isotropic 3D magnetic resonance imaging sequences References 20 Biomechanical Assessment of Soft Tissues in the Foot and Ankle Using Ultrasound 20.1 Introduction 20.1.1 Ultrasound imaging, how it works 20.2 Ultrasound assessment of structural changes: the effect of weightbearing activities 20.2.1 Assessment of plantar soft tissue thickness in relation to weightbearing activities 20.2.2 Assessment of plantar fascia thickness in relation to weightbearing activities 20.2.3 Assessment of Achilles tendon thickness in relation to weightbearing activities 20.2.4 Summary and limitations of weightbearing ultrasound 20.3 Ultrasound assessment combined with measurement of load 20.3.1 Ultrasound combined with load cells to assess the mechanical properties of the plantar soft tissue 20.3.2 Ultrasound combined with dynamometry to assess the mechanical properties of Achilles tendon 20.3.3 Summary and limitations of ultrasound assessment combined with measurement of load 20.4 Ultrasound elastography (sonoelastography) 20.4.1 Ultrasound elastography to assess the mechanical properties of plantar soft tissue 20.4.2 Ultrasound elastography to assess the mechanical properties of plantar fascia 20.4.3 Ultrasound elastography to assess the mechanical properties of Achilles tendon 20.4.4 Summary and limitations of ultrasound elastography 20.5 Conclusion and future areas of research References 21 3D Surface Scanning of the Foot and Ankle 21.1 Introduction 21.1.1 The history and development of 3D scanning 21.1.2 Technologies 21.1.2.1 Contact scanners (coordinate measuring machines) 21.1.2.2 Noncontact scanners 21.2 Foot-specific applications and considerations 21.2.1 Reliability and comparisons to other techniques 21.2.2 Population studies 21.2.3 Orthoses and footwear 21.2.4 Musculoskeletal models 21.2.5 Bones and other internal anatomy 21.3 Areas of future biomechanical research References 22 Cadaveric Gait Simulation 22.1 Introduction 22.2 Techniques for dynamic gait simulation 22.3 Limitations of dynamic gait simulation 22.4 Clinical applications of dynamic gait simulation 22.5 Areas of future biomechanical research 22.6 Conclusion References 23 Finite Element Modeling 23.1 Introduction 23.2 Basic concepts of finite element modeling 23.3 Applications of finite element analysis in foot biomechanics 23.3.1 Simulation of the interaction between foot and footwear 23.3.2 Simulation of healthy foot biomechanics 23.3.3 Finite element modeling for the in vivo material characterization of soft tissues 23.3.4 Simulation of pathological conditions 23.3.4.1 Biomechanics of the pathologic foot 23.3.4.2 Study of surgical interventions 23.4 Modeling strategies 23.4.1 Geometry design 23.4.1.1 3D modeling versus 2D modeling 23.4.1.2 Modeling of the entire foot compared to anatomically focused modeling 23.4.1.3 Anatomically detailed compared to idealized modeling 23.4.2 Meshing 23.4.2.1 Element type selection 23.4.2.2 Mesh convergence 23.4.3 Material properties 23.4.3.1 Bone and cartilage 23.4.3.2 Ligaments and tendons 23.4.3.3 Soft tissues 23.4.4 Solver selection 23.4.5 Reliability assessment 23.5 Limitations and future research toward clinically applicable finite element modeling 23.6 Summary References 24 Musculoskeletal Modeling of the Foot and Ankle 24.1 Introduction 24.1.1 Musculoskeletal models and their development 24.1.2 Validation techniques 24.1.3 Challenges in modeling the foot and ankle 24.2 Foot specific models and applications 24.3 Areas of future biomechanical research References 25 Predicting and Preventing Posttraumatic Osteoarthritis of the Ankle 25.1 Introduction: pathomechanical origins of posttraumatic osteoarthritis 25.2 Pathomechanics I: acute joint injury severity 25.3 Pathomechanics II: chronic stress aberration 25.4 Pathomechanics III: altered kinematics 25.5 Areas of future biomechanical research 25.5.1 Posttraumatic ankle osteoarthritis: opportunities for intervention informed by pathomechanical knowledge 25.6 Summary/conclusion References 26 Mechanics of Biological Tissues 26.1 Introduction 26.2 Materials and methods 26.2.1 Finite element modeling of the foot 26.2.2 Formulation of constitutive models 26.2.2.1 Linear elastic constitutive models 26.2.2.2 Hyperelastic constitutive models 26.2.2.3 Visco-hyperelastic model 26.2.3 Identification of constitutive parameters 26.2.3.1 Constitutive parameter identification for bone 26.2.3.2 Constitutive parameter identification for cartilage 26.2.3.3 Constitutive parameter identification for plantar soft tissue 26.2.3.4 Constitutive parameter identification for ankle ligaments 26.2.4 Numerical analyses of foot functionality 26.2.4.1 Ankle movements 26.2.4.2 Gait cycle 26.2.4.3 Foot and footwear interaction 26.2.4.4 Diabetic condition 26.2.5 Limitations of computational modeling 26.2.6 Future biomechanics research 26.3 Conclusion References 27 Clinical Examination of the Foot and Ankle 27.1 Introduction 27.2 Demographics 27.3 Vital signs 27.4 Patient history 27.5 Assessment of pain 27.6 Visual observation/inspection 27.6.1 Skin 27.6.2 Edema 27.6.3 Atrophy 27.6.4 Temperature 27.6.5 Scarring 27.6.6 Callus patterns 27.6.7 Exostoses 27.6.8 Ankle and foot deformities 27.7 Lower extremity alignment 27.8 Foot posture or foot shape 27.8.1 Planus foot type 27.8.2 Cavus foot type 27.9 Limb length 27.10 Radiographic examination 27.11 Range of motion/flexibility/joint mobility 27.12 Joint mobility 27.13 Ligamentous/stability testing 27.14 Tendon 27.15 Muscle strength 27.16 Sensory testing 27.17 Circulation 27.18 Foot and ankle specific testing 27.19 Footwear examination 27.20 Functional assessment 27.21 Outcomes assessment 27.22 Areas of future biomechanical research References 28 Foot Type Biomechanics 28.1 Introduction 28.2 Structural foot type 28.3 Functional foot type 28.4 Foot type biomechanics 28.5 Association with pain and injury 28.5.1 Pain and injury 28.6 Treatments 28.7 Areas of future biomechanical research References 29 Traumatic Foot and Ankle Injuries 29.1 Introduction 29.2 Pilon fractures 29.2.1 Etiology and pathophysiology 29.2.2 Symptoms 29.2.3 Diagnostics/classification 29.2.4 Treatment 29.3 Calcaneal fractures 29.3.1 Etiology and pathophysiology 29.3.2 Symptoms 29.3.3 Diagnostics/classification 29.3.4 Treatment 29.4 Talus fractures 29.4.1 Etiology and pathophysiology 29.4.2 Symptoms 29.4.3 Diagnostics/classification 29.4.4 Treatment 29.5 Tarsometatarsal (Lisfranc) injuries 29.5.1 Etiology and pathophysiology 29.5.2 Symptoms 29.5.3 Diagnostics/classification 29.5.4 Treatment 29.6 Metatarsal fractures 29.6.1 Etiology and pathophysiology 29.6.2 Symptoms 29.6.3 Diagnostics/classification 29.6.4 Treatment 29.7 Midfoot crush injuries 29.7.1 Etiology and pathophysiology 29.7.2 Symptoms 29.7.3 Treatment 29.8 Acute ankle sprains 29.8.1 Etiology and pathophysiology 29.8.2 Symptoms 29.8.3 Treatment 29.9 Syndesmosis tears 29.9.1 Etiology and pathophysiology 29.9.2 Symptoms 29.9.3 Treatment 29.10 Achilles tendon rupture 29.10.1 Etiology and pathophysiology 29.10.2 Symptoms 29.10.3 Treatment 29.11 Areas of future research References 30 The Pediatric Foot 30.1 Introduction 30.2 Common pathologies affecting pediatric feet 30.2.1 Congenital foot deformities 30.2.2 Developmental foot deformities 30.2.3 Foot pathologies associated with other conditions 30.3 Functional assessment of the pediatric foot 30.4 Areas for future research References 31 Neurological Foot Pathology 31.1 Introduction 31.2 Stroke 31.2.1 Pathology related to the musculoskeletal system 31.2.2 Impact on kinematics 31.2.3 Impact on foot function 31.2.4 Clinical treatment 31.3 Cerebral palsy 31.3.1 Definition 31.3.2 Structural deformities and gait deviations 31.3.3 Treatment 31.4 Toe walking 31.4.1 Diagnosis and etiology 31.4.2 Biomechanical and musculoskeletal function 31.4.3 Treatment 31.5 Peripheral neuropathy 31.5.1 Background 31.5.2 Musculoskeletal and movement implications 31.6 Foot drop 31.6.1 Pathology 31.6.2 Impact on biomechanics 31.6.3 Treatment 31.7 Tarsal tunnel syndrome 31.7.1 Pathology 31.7.2 Impact on biomechanics 31.7.3 Treatment 31.8 Morton’s neuroma 31.8.1 Pathology 31.8.2 Impact on biomechanics 31.8.3 Treatment 31.9 Charcot foot 31.9.1 Pathology 31.9.2 Impact on biomechanics 31.9.3 Treatment 31.10 Charcot-Marie-Tooth disease 31.10.1 Pathology 31.10.2 Impact on biomechanics—pediatric and young adult 31.10.3 Impact on biomechanics 31.10.4 Treatment 31.11 Friedreich’s ataxia 31.11.1 Background and pathology 31.11.2 Gait analysis 31.11.3 Musculoskeletal effects 31.11.4 Clinical treatment 31.12 Poliomyelitis 31.12.1 Pathology 31.12.2 Current status 31.12.3 Impact on biomechanics 31.12.4 Treatment 31.13 Areas of Future Research References 32 Chronic Foot and Ankle Injuries 32.1 Introduction 32.1.1 Chronic injury through microtrauma 32.1.2 Chronic injury through macrotrauma 32.1.3 Impairment-based rehabilitation model for treating chronic injuries 32.1.4 Role of patient-oriented outcomes 32.2 Chronic ankle instability 32.2.1 Anatomy overview 32.2.2 Etiology 32.2.2.1 Mechanism of injury and pathomechanics 32.2.3 Clinical impairments 32.2.3.1 Range of motion 32.2.3.2 Strength 32.2.3.3 Balance 32.2.3.4 Functional activity 32.2.4 Treatment 32.2.4.1 Acute management 32.2.4.2 On-going management 32.3 Plantar fasciitis 32.3.1 Anatomical overview 32.3.2 Etiology 32.3.2.1 Mechanism of injury and pathomechanics 32.3.3 Clinical impairments 32.3.3.1 Range of motion 32.3.3.2 Strength 32.3.3.3 Functional activity 32.3.4 Treatment 32.3.4.1 Acute management 32.3.4.2 On-going management of clinical impairments 32.4 Tendinopathy (Achilles, peroneal, and posterior tibialis) 32.4.1 Anatomical overview 32.4.2 Etiology 32.4.2.1 Mechanism of injury and pathomechanics 32.4.2.1.1 Achilles tendon 32.4.2.1.2 Tibialis posterior tendon 32.4.2.1.3 Peroneal tendon 32.4.3 Clinical impairments 32.4.4 Treatment 32.5 Stress fractures (navicular, metatarsals) 32.5.1 Anatomical overview 32.5.2 Etiology 32.5.2.1 Mechanism of injury and pathomechanics 32.5.3 Clinical impairments 32.5.4 Treatment 32.6 Sesamoiditis 32.6.1 Anatomical overview 32.6.2 Etiology 32.6.2.1 Mechanism of injury and pathomechanics 32.6.3 Clinical impairments 32.6.4 Treatment 32.7 Retrocalcaneal bursitis 32.7.1 Anatomical overview 32.7.2 Etiology 32.7.2.1 Mechanism of injury and pathomechanics 32.7.3 Clinical impairments 32.7.4 Treatment 32.8 Areas of future research for chronic foot and ankle injuries References 33 Hallux Valgus 33.1 Introduction 33.2 Prevalence 33.3 Etiology 33.3.1 Genetics and race 33.3.2 Structural and biomechanical factors 33.3.3 Footwear 33.4 Diagnosis and imaging 33.4.1 Clinical diagnosis 33.4.2 Radiographic assessment 33.4.3 Ultrasound 33.4.4 Computed tomography 33.4.5 Magnetic resonance imaging 33.5 Clinical presentation 33.5.1 Foot pain 33.5.2 Footwear 33.5.3 Self-reported function and quality of life 33.6 Functional outcomes 33.6.1 Balance and falls 33.6.2 Hallux flexion and abduction 33.6.3 Gait analysis 33.6.3.1 Kinematics 33.6.3.2 Plantar pressures 33.6.3.3 Muscle activity 33.6.3.4 Temporospatial parameters 33.7 Treatment pathways 33.7.1 Nonsurgical treatment 33.7.1.1 Expert opinion and current practice 33.7.1.2 Foot orthoses 33.7.1.3 Splints and toe separators 33.7.1.4 Manual therapy 33.7.1.5 Taping 33.7.1.6 Exercise 33.7.1.7 Botulinum toxin A injection 33.7.2 Surgical treatment 33.8 Future directions for research 33.9 Summary References 34 Osteoarthritis of the Foot and Ankle 34.1 Introduction 34.1.1 Osteoarthritis symptoms and diagnosis 34.1.2 Structural changes 34.1.3 Risk factors and classification of osteoarthritis 34.1.4 Foot and ankle osteoarthritis subtypes 34.2 First metatarsophalangeal joint osteoarthritis 34.2.1 Etiology and impact 34.2.2 Clinical findings 34.2.3 Structural and biomechanical features 34.2.4 Clinical and biomechanical effects of conservative treatment 34.3 Midfoot osteoarthritis 34.3.1 Etiology and impact 34.3.2 Clinical findings 34.3.3 Structural and biomechanical features 34.3.4 Clinical and biomechanical effects of conservative treatment 34.4 Ankle osteoarthritis 34.4.1 Etiology and impact 34.4.2 Clinical findings 34.4.3 Structural and biomechanical features 34.4.4 Clinical and biomechanical effects of conservative treatment 34.5 Areas of future biomechanical research 34.6 Summary References 35 Diabetic Foot Disease 35.1 Background on diabetes 35.2 Overview of key negative outcomes of diabetic foot disease 35.2.1 Diabetic peripheral neuropathy 35.2.2 Peripheral vascular disease 35.2.3 Diabetic plantar ulceration 35.2.4 Foot deformities 35.2.5 Lower-extremity fractures 35.2.6 Charcot neuroarthropathy 35.2.7 Lower extremity amputation 35.3 Risk factors for the development and progression of diabetic foot disease 35.4 Changes in kinematics and kinetics in diabetic foot disease 35.5 Changes in tissue characteristics 35.5.1 Muscle: fatty infiltration and reduction of intrinsic foot muscle volumes 35.5.2 Bone 35.5.3 Cartilage 35.5.4 Tendon 35.5.5 Plantar fascia 35.6 The relationship between foot deformities and plantar ulceration 35.7 The relationship between lower extremity fractures and Charcot neuropathic osteoarthropathy 35.8 Areas of future biomechanical research References 36 Rheumatic Foot Disease 36.1 Introduction 36.2 Rheumatoid arthritis 36.2.1 Early rheumatoid arthritis 36.2.2 Established rheumatoid arthritis 36.3 Spondlyarthropathies 36.4 Juvenile idiopathic arthritis 36.5 Connective tissue disorders 36.6 Gout 36.7 Future research References 37 The Aging Foot 37.1 Changing properties and functions of foot tissues 37.1.1 Bone 37.1.2 Cartilage 37.1.3 Muscle 37.1.4 Tendon 37.1.5 Ligament 37.1.6 Skin 37.1.7 Neural 37.1.8 Fat pad 37.2 Foot posture and morphology 37.2.1 Anthropometrics 37.2.2 Foot posture 37.2.3 Arch height 37.2.4 Joint range-of-motion 37.3 Foot function (kinematics/kinetics/plantar pressures) 37.3.1 Kinetics 37.3.1.1 Ground reaction forces 37.3.1.2 Joint moments and powers 37.3.1.3 Plantar pressures 37.3.2 Kinematics 37.3.2.1 Ankle and foot 37.4 Foot posture, foot disorders, and mobility limitations 37.4.1 Foot posture and foot deformity 37.4.2 Foot posture and foot symptoms 37.4.3 Foot posture, mobility limitations, and falls 37.5 Areas for future research References 38 Biomechanics of Athletic Footwear 38.1 Introduction 38.2 Anatomy of a running shoe 38.3 Biomechanics of athletic footwear design 38.3.1 Cushioning 38.3.2 Hindfoot stability 38.4 Types of shoes and their features 38.4.1 Casual shoes 38.4.2 Running shoes 38.4.3 Racing flats & spikes 38.4.4 Marathon shoes 38.4.5 Other sports shoes 38.4.6 New shoe innovations 38.4.6.1 Footwear embedded energy harvester 38.4.6.2 Lacing systems 38.4.6.3 3D printed midsoles and outsoles 38.4.7 Graphene outsoles 38.5 Shod versus barefoot 38.6 Footwear related injuries 38.7 Future footwear research References 39 Minimal Shoes: Restoring Natural Running Mechanics 39.1 Introduction 39.2 Brief history of running footwear 39.3 Biomechanics of barefoot and conventional shod running 39.3.1 Barefoot running pattern 39.3.2 Conventional shod running pattern 39.3.3 Comparison of mechanics between conventional shod and barefoot running 39.4 Minimal footwear running 39.4.1 Definition of full minimalist footwear 39.4.2 Comparison of full minimal to barefoot running 39.4.3 Comparison of full minimal to partial minimal shoes 39.4.4 Comparison of full minimal to conventional footwear 39.5 Effect of minimal shoes on the foot musculoskeletal system 39.6 Summary 39.7 Future research References 40 Foot Orthoses 40.1 Introduction 40.1.1 Design and manufacture of foot orthoses 40.2 Biomechanical effects of foot orthoses 40.2.1 Kinematic effects of foot orthosis 40.2.2 Kinetic effects of foot orthosis 40.2.3 Effects of foot orthosis on plantar pressure 40.2.4 Effects of foot orthosis on muscle activity patterns 40.3 Effects of foot orthosis on clinical conditions 40.3.1 Rheumatoid arthritis 40.3.2 Symptomatic flat foot 40.3.3 Heel pain (plantar fasciitis) 40.3.4 Osteoarthritis 40.3.5 Sports injuries and other conditions 40.4 Areas of future research References 41 Ankle-Foot Orthoses and Rocker Bottom Shoes 41.1 Introduction 41.2 Ankle-foot orthoses 41.2.1 Controlling rotational motion 41.2.2 Controlling translational motion 41.2.3 Controlling axial forces 41.2.4 Altering the line of action of the ground reaction force 41.3 Rocker bottom shoes 41.4 Roll-over shape 41.5 Patient populations 41.5.1 Stroke 41.5.2 Cerebral palsy 41.5.3 Ankle arthritis 41.5.4 Limb salvage 41.6 Design and prescription of ankle-foot orthosis 41.6.1 Conventional versus advanced 41.6.2 Articulated versus nonarticulated 41.7 Design and prescription of rocker bottom shoes 41.8 Variations on materials 41.9 New designs 41.10 Sport applications 41.11 Areas of future research References 42 Diabetic Footwear 42.1 Introduction 42.2 Foot biomechanics and offloading 42.3 The biomechanical effect of diabetic footwear and offloading devices 42.4 Footwear and offloading for ulcer healing 42.5 Diabetic footwear for ulcer prevention 42.6 Footwear and offloading adherence 42.7 Other considerations 42.8 Future research 42.9 Conclusions References 43 Reconstructions for Adult-acquired Flatfoot Deformity 43.1 Introduction 43.2 Hindfoot valgus 43.2.1 Bony anatomy 43.2.2 Ligament failure 43.2.3 Surgical reconstruction 43.3 Forefoot external rotation 43.3.1 Bony anatomy 43.3.2 Ligament and tend