No apparatus that allows of the patient walking is of any value. If the deformity is marked, there should be no hesitation in having recourse to operation by one or other of the various methods of osteotomy.
In severe cases it may be found that when the deformity is corrected by osteotomy, the patella shows a tendency to be dislocated laterally on flexion of the knee. This may be prevented by putting up the limb in the attitude of slight genu varum.
The most difficult cases to treat are those in which, owing to curving of the lower part of the shaft of the femur with the convexity forwards, the knee is permanently flexed and cannot be completely extended.
Other forms of genu valgum are relatively rare. There is a congenital form arising from faulty position of the limbs in utero; a traumatic form following fracture or epiphysial separation in the region of the knee; and a paralytic form, usually combined with flexion, in cases of spastic paralysis. Finally, genu valgum may be a result of various forms of osteomyelitis of the lower end of the femur, or of disease in the knee-joint, such as tuberculosis, arthritis deformans, or Charcot's disease.
Genu Varum—Bow-knee.—In this deformity, which is the converse of genu valgum, the leg joins the thigh at an angle which is open medially. It is almost invariably bilateral, is of rachitic origin, and is frequently associated with bow-legs ([Fig. 141]). The tibia takes a greater share in its production than the femur. Although an ungainly deformity, it is much less frequently the source of complaint than knock-knee, because it scarcely interferes with locomotion—as a matter of fact, the subjects of bow-knee, although short in stature, are unusually sturdy on their legs. An extreme example of the deformity is shown in [Fig. 141].
Fig. 141.—Bow-knee in Rickety Child.
Treatment is carried out on the same lines as in genu valgum.
Rickety Deformities of the Bones of the Leg—Bow-leg.—These deformities are common in children; are nearly always bilateral and symmetrical, and may be associated with knock-knee or bow-knee. They may occur before the child is able to walk, the bones bending in the attitude in which the limbs are habitually placed—over the nurse's knee, for example, or as they are crossed underneath the child in sitting. In children who are able to walk, the curve is due to the weight of the body acting on the softened bones. In either case, the bending may be increased by the traction of muscles, and sometimes by the occurrence of greenstick fracture. The most common deformity is a uniform curvature of the bones laterally and forwards, or a more acute bend in the lower thirds of their shafts. In some cases the chief curvature is forwards. The ungainliness in walking may be added to by flat-foot. Backward curving of the upper end of the tibia has been already described as one of the causes of genu recurvatum. The most extreme deformities are met with in rickety dwarfs.