Orthopaedic Mechanics

Contributors

Preface


1. Tibiometry

I. Introduction

II. Theory

A. Model Set-Up

B. Model Set-Up

C. The Determination of the Moment of Inertia

III. Design

IV. Procedure

A. Clinical Testing

B. Results

C. Unresolved Technical Problems

D. Future Evolution of the Device

References


2. Finite Element Stress Analysis of the Human Knee

I. Introduction

II. Biological Background

A. Anatomy of the Knee Joint

B. Articular Cartilage

C. Subchondral Trabecular Bone

D. Degenerative Joint Disease (Osteoarthritis)

III. Previous Stress Analyses of Synovial Joints

IV. Synovial Joint Loads and Material Properties

A. Tibiofemoral Forces and Contact Areas

B. Mechanical Properties of Articular Cartilage

C. Mechanical Properties of Trabecular Bone

V. Finite Elements Stress Analysis of the Knee

A. Finite Element Method

B. Stress Analysis of the Normal and Arthritic Proximal Tibia

C. Discussion

VI. Applications to Total Knee Design Evaluations

A. Tibial Component Fixation in Total Knee Prosthesis

B. Patellar Resurfacing Procedures

References


3. Endoprosthesis Features

I. Introduction

II. Intramedullary Devices

III. Structure of Bone

IV. Evaluation of Elastic Stress Distribution

A. First Approximation

B. Elastic Solution

C. Influence of Concentrated Forces

V. Influence of Viscoelasticity, Orthotropy and Non-Homogeneity

VI. Closure

Appendix

Addendum

References


4. Human Locomotion Analysis

I. Introduction

A. Relevance

B. Gait Analysis: Previous Works and the Scope of the Chapter

II. Three-Dimensional Gait Analysis

A. Data Acquisition

B. Data Utilization to Help Formulate the Terms Required for the Governing Equations

C. Determination of the Joint And Muscle Forces (by Means of a Dynamic Analysis of the Limb)

III. Error Analysis

A. Analytic Representation of the Monitored Kinematic Variables

B. Velocities and Accelerations

IV. Simplified Two-Dimensional Analysis in the Sagittal Plane

A. Determination of the Muscular Torques

B. Data Acquisition

C. Influence of the Measurements Errors on the Computed Torques

D. Analysis of Muscular Activity

V. Results From Two-Dimensional Analysis in the Sagittal Plane

A. Kinematics and Ground Reactions

B. Joint Torques and Muscle Activity Coordination

C. Electrical Activity and Instantaneous Length of Muscles

VI. Clinical Evaluation of Normal and Pathological Gait By Means of the Butterfly Diagrams

A. Equipment and Procedure

B. Butterfly-Patterned Dynamic Ground Reaction Vector Diagrams of Normal Subjects

C. Preliminary Observations on Abnormal Cases

D. Reproducibility of the Vector Diagrams

Appendix A

Appendix B

Acknowledgement

References


5. Torqheels

I. Biomechanical Aetiology of Lower Extremity Rotational Deformities

A. Internal Rotation

B. External Rotation

II. Correction Approaches

A. Application Of Opposing Rotation

B. Static Versus Dynamic Treatment

III. Torqheel—A Ground Contact Rotational Device

A. Torques Produced by Torqheels

B. Prescription and Installation Recommendations

C. Wear and Maintenance

IV. Kinematic Analysis of Wedging

V. Clinical Results

References


6. The Relationship Between Design and Material Selection in Orthopaedic Implants

I. Introduction

II. Principles of Material Selection

A. Structure of Materials

B. Mechanical Properties

C. Corrosion and Degradation

III. Principles of Biocompatibility

A. Local Tissue Response to Implanted Materials

B. Systemic Effects Following Implantation

C. Hypersensitivity

D. Infection

E. Carcinogenicity

IV. Materials in Clinical Use

A. Metals

B. Plastics

C. Ceramics and Glasses

V. Internal Fixation

A. Fracture Healing

B. Rigidity in Fracture Healing

C. The Strength of Fixation Devices

D. Screws for Fracture Plating

E. Examples of Implants for Internal Fixation

F. Materials for Internal Fixation

VI. Tribological Characteristics of Total Joint Replacement Prostheses

A. Friction and Lubrication

B. Wear

C. Summary of Materials Considerations

VII. The Stabilization of Prostheses

A. Impaction and Mechanical Fixation

B. Cements

C. Tissue Ingrowth into Porous Surfaces

D. Adhesion via Chemical Bonding

VIII. Total Joint Replacement Prostheses

A. Replacement of the Hip Joint

B. Replacement of the Knee Joint

C. Replacement of Shoulder, Elbow and Ankle Joints

D. Replacement of Finger Joints

IX. Conclusions

Index