Comparative anatomy helps to define among surgical procedures, those that are able to restore early walking function using really useful structures, without necessarily respecting the normal anatomy. This book proposes an original vision based on the following ideas : ? The cure is complete only if it occurs quickly, which is vital for vulnerable patients. ? The surgical goal isn't the anatomical restitution ad integrum, but to resore the fonction, that of the permanent terrestrial human bipedalism. To identify it, put it back into its evolutionary context and compare it to the anatomo-functional models of our closest relatives, the great apes. ? Achieving this dual objective through new surgical techniques (percutaneous and minimally invaseve), associated with biomechanical data for immediate and total support.