_Treatment._--Under the age of six, and particularly in children, who are actively growing, the bones will probably straighten if the child is treated for rickets and kept off his feet; well-padded lateral splints are applied as recommended for knock-knee, and these should be taken off at intervals for massage and douching. Above the age of six, the choice lies between osteoclasis and osteotomy. In performing osteotomy the bone is either simply divided or a segment is resected. The fibula can usually be forcibly straightened, but may require to be divided through a separate incision. In aggravated cases it may also be necessary to lengthen the tendo Achillis. The deformities of the bones of the leg in _inherited syphilis_, _ostitis deformans_, and _osteomalacia_ have already been described. #Congenital Deficiencies of the Bones of the Leg.#--The _tibia_ may be absent completely or in part, more often on one side than on both sides. In either case the leg is short and stunted, the knee is flexed, the foot occupies the position of extreme equino-varus, and the limb is useless. The extent of the defects is demonstrated by the Röntgen rays. Among other defects with which it may be associated, absence or deficient development of the patella is the most frequent. When the upper end of the tibia is absent, the fibula articulates with the lateral condyle of the femur. The operative treatment aims at correcting the flexion at the knee, the equino-varus deformity of the foot, and at substituting the fibula for the absent tibia. The deficiency of the upper end may be compensated for by implanting the head of the fibula between the condyles of the femur, and that at the lower end by splitting the fibula so as to form a socket for the talus. Amputation should be avoided, as even a dwarfed leg and foot improves the service of an artificial limb. A modification of the O'Connor extension boot may be employed.