The primary purpose of this book was to assemble a comprehensive collection of current knowledge on minimally invasive arthroplasty technique. The first section of this book was designed to answer the question as to whether minimally invasive approaches to hip and knee replacement were needed. The next several sections detail specific minimally invasive approaches to the hip and knee and also present a corporate perspective on minimally invasive surgery. Within the text of this book, many issues will be presented, some of which are incision length, single versus multiple incision, muscle sparing versus muscle splitting, in situ bone cuts versus dislocation of the joint, and intra-medullary versus extra-medullary instrumentation Although the role of navigation in minimally invasive arthroplasty is not well defined, there is a strong belief that the combination of minimally invasive surgery and computer-assisted surgery together may be the future, combining the principles of high precision surgery with the advantages of soft tissue and muscle sparing surgical approaches. The diminished visualization in less invasive surgery may be compensated by the advantages and enhanced visualization provided by navigation. The final sections of the book provide perspectives on whether minimally invasive surgery is a winning concept and whether new instruments and new prosthetic designs are required. Finally, the issue of teaching minimally invasive and computer-assisted surgery is explored.