Arthroplasty, or the technic for the formation of new joints, may be divided into seven different stages in its evolution, and each stage has been initiated or created by the work of a single individual and then his succeeding school. These stages are: The formation of fibrous or flail joints, as of the shoulder and elbow (Langenbeck, Ollier, Julius Wolff and others). These were desired sequences following resections for diseased joints, as tuberculosis, syphilis, pus infections, etc. The restoration of mobility in a bony ankylosed joint by the interposition of muscle and fibrous tissue between the separated ends at the ankylosed joint, as in the mandible (Helferich, 1893, who was the father of this method). Pseudo-arthrosis developing after osteotomies in the neighborhood of joints (Lorenz), as in hip ankylosis. The transplantation of pedicled flaps of fascia and fat and capsule, with the production of a movable, sliding joint and a