The 32nd Japanese Hip Society (JHS) Congress was held November 6–8, 2005, in Niigata, Japan. Guest speakers from many countries and specialists for hip disease presented papers that focused on joint preservation for osteoarthritis of the hip, joint preservation for aseptic necrosis of the femoral head, treatment for epiphyseolysis capitis femoris, and up-to-date information and knowledge on joint arthroplasty. Altogether, there were many important presentations about joint preservation and replacement. This book covers the main themes of the congress. The starting point for the treatment of hip disease depends on how we can preserve the natural hip joint and on steps leading to regeneration of the diseased, injured, or destroyed joint. Preservation and regeneration treatments following traditional and theoretical methods do not need to use expensive materials, such as the arti?cial joints used in arthroplasty. On the other hand, preservation and regeneration tre- ments are dif?cult to perform and require a lengthy rehabilitation period.