The International Hip Dysplasia Institute (IHDI) is a collaborative, international, not-for-profit effort to improve the health and quality of life of those affected by hip dysplasia. Our goal is to provide education to patients, families, and physicians as the most comprehensive and reliable resource for knowledge about hip dysplasia in its various forms. What is Hip Dysplasia? Hip Dysplasia means that the bones of the hip joint are not aligned correctly. It affects thousands of children and adults each year and is known by many different names: Developmental Dysplasia of the Hip (DDH) Hip Dislocation Congenital Dislocation of the Hip (CDH)