Biomechanics of Lower Limb Prosthetics (eBook)

Biomechanics of Lower Limb Prosthetics 1
Lower Limb Prosthesis 15
1.1 A Need for Better Functionality of Lower Limb Prostheses 15
1.2 Normalization of Prosthetic Gait Parameters as a Way for Increasing the Prosthesis’ Functionality 18
1.2.1 Biomechanics and Prosthetics 18
1.2.1.1 Why is Self-Analysis of Gait Difficult to Conduct? 18
1.2.1.2 A Sound Leg Does not Feel the Body’s Weight 18
1.2.1.3 How Does the Anatomical Leg Flex and Extend During Gait? 21
1.2.2 Anthropomorphicity of Lower Limb Prostheses 21
1.2.3 Influence of Moment in Prosthetic Ankle Joint on the User’s Comfort 26
1.2.4 Influence of a Moment in Prosthetic Ankle Joint on the Existing Knee Joint of the Involved Leg 32
1.2.5 Measurements of the Pressures on the Residuum from the Socket 34
1.3 Structure of Study Design for Development of Lower Limb Prosthesis 38
References 39
Biomechanical Investigations of Sound and Prosthetic Gait 42
2.1 Kinematic and Dynamic Analysis of Motion 42
2.2 Modeling the Human Body for Motion Analysis 45
2.3 Equipment for Motion Analysis 45
2.4 Architecture of Computerized Gait Analysis 47
2.5 Interpretation of Gait Analysis Results 49
References 50
Theory of Ballistic Gait in Prosthetics 52
3.1 .Ballistic Synergy in Normal Gait 52
3.1.1 .Generation of the Propulsive “Push-Off” 53
3.1.2 .Regular and Intentional Push-Off 54
3.1.2.1 .Regular Push-Off 55
3.1.2.2 .Intentional Push-Off 56
3.1.3 .Computer Simulation of Regular and Intentional Gait 57
3.1.3.1 .Simulation of the Propulsion in Regular Gait 58
Simulation of the Propulsion in Static Stage 59
Simulation of the Intentional Propulsion 59
3.1.4 .“Angle–Moment” Dependency in Ankle During Normal Gait 60
3.1.5 .Contribution of the Knee to Ballistic Synergy 61
3.1.6 .Implications for Prosthetics 65
3.2 .Active and Passive Moments in Joints 65
3.3 .Model of a One-Step Cycle: Passive Phase 66
3.3.1 .Phase “A” of a Step Cycle 67
3.3.2 .Phase “M” of a Step Cycle 68
3.3.3 .Working Model Simulation of the Balancing 69
3.4 .A Model of a One-Step Cycle 71
3.4.1 .Active Phase “MAHA.2.” 71
3.5 .Generation of Propulsion in Norm and Disruption of Ballistic Synergy in Prosthetic Gait 73
3.6 .Modeling of One-Leg Standing 77
3.7 .Implication for Prosthetic Design 79
References 80
Theory of Designing the Anthropomorphic Lower Limb Prostheses 84
4.1 Synthesis of a Mechanism for Prosthetic Joint 84
4.1.1 Anatomical Prototype for Modeling a Moment 84
4.1.2 Trochoidal Model of the Spring Function of the Anatomical Foot 85
4.1.3 Synthesis of a Mechanism for Prosthetic Ankle 92
4.2 Development and Testing of the Rolling Joint Foot and Ankle 97
4.2.1 Development of the Rolling Joint Foot and Ankle 97
4.2.1.1 Tuning Features 99
4.2.1.2 Self-Tuning to Walking Speed 100
4.2.2 Mechanics Tests of the Rolling Joint Foot and Ankle 100
4.2.2.1 Additional Components of Safety of the Prosthesis’s Use 101
4.2.2.2 Flexural Tests 101
Calculation of the Moment of Resistance Using Raw Data 103
Inversion/Eversion 103
4.2.2.3 Rotational Stiffness 104
4.2.2.4 Mechanical Tests of Rolling Joint Foot and Ankle: Conclusion 105
4.3 Development and Evaluation of the Rolling Joint Knee 106
4.3.1 Design Approach 106
4.3.2 RJ Knee Mechanism 108
Stance Phase 108
Swing Phase 109
4.3.3 Mechanical Testing of the Rolling Joint Knee Unit 110
4.3.4 Moment of Resistance to Knee Flexion 111
4.3.5 Moment of Resistance to the Knee Adduction/Abduction 112
4.3.6 Mechanical Tests of RJ Knee: Conclusion 113
References 113
Biomechanical Evaluation of Experimental Prostheses 116
5.1 Purpose of Biomechanical Evaluation 116
5.2 Biomechanical Testing of RJFA 117
5.2.1 Knee Performance 117
5.2.2 Forces and Pressures on Residuum 118
5.2.3 Moment of Dorsiflexion 121
5.2.4 Biomechanical Testing of RJFA with Adjustable Stiffness 122
5.2.5 Biomechanical Testing of RJFA: Conclusion 126
5.3 Biomechanical Testing of the Rolling Joint Leg 126
5.3.1 Symmetry of Distant-Time Characteristics Between Involved and Uninvolved Sides 128
5.3.2 Moment of Resistance to Knee Flexion–Extension Moment 128
5.3.3 Forces and Pressures on Residuum and Their Link with Ankle Moment 130
5.3.4 Contribution of the RJ Knee vs. RJ Foot 131
5.3.5 Biomechanical Testing of Rolling Joint Knee: Conclusion 132
5.4 Long-Term Outcomes of Rehabilitation with RJFA 132
References 134
Principle of Spectral Reciprocity in Biomechanics of Locomotion 136
6.1 Tuning Out of Resonance in Biomechanics of Locomotion 136
6.2 When Resonance is Unwanted 136
6.3 Model of Spectral Optimization 137
6.4 Implication for Prosthetics and Orthotics 140
References 141
Biomechanical Aspects of Direct Skeletal Attachment of Lower Limb Prostheses 143
7.1 Methodology of Direct Skeletal Attachment 143
7.2 The Challenge of Longevity for Direct Skeletal Attachment 143
7.2.1 Longevity of Skin–Implant Seal 144
7.2.2 Longevity of the Bone–Implant Bond 145
Lessons from Arthroplasty 145
7.2.2.1.1 Strength Requirements for the Implant 147
Recommendations for Implant’s Design 148
Recommendations for Prosthesis’s Design 149
Biomechanical Aspects of DSA: Conclusions 149
Conclusion 149
References 150
Index 152