Osteotomy is the oldest and the most popular operation for the correction of severe rachitic deformities of the legs in children, yet it has many disadvantages when compared with osteoclasis performed with the aid of the perfected Grattan osteoclast. Some of its disadvantages are: the production of a compound instead of a simple fracture; time required for operation; the danger of infection which, though it may be slight, nevertheless exists; time, care and expense necessary for antiseptic precautions, and the pain that always accompanies an open wound. But the most serious objection to osteotomy is the delayed union as compared with union after osteoclasis. This is undoubtedly due to the severing of the continuity of the bone shaft and the carrying of soft tissue into the open space with the chisel. This delayed union has frequently to be supplemented by postoperative treatment, which is never required after rapid osteoclasis. Tubby