OEN U VALGUAI (KNOCK-KNEE) Gem' valgum is an outward deviation of the leg. The leg appears to incline inward from the side in the region of the knee and forms there an angle opening outward. When both legs are affected the knees are thrust together in the form of an X (x-knee or knock-knee). The ankles stand apart from each other in recumbent position as well as in the erect posture, especially if the patella is accurately placed at the front. A photograph, Röntgen picture, or a drawing of the curvatures will give the best information as to the degree of curvature, but the patella must always be kept in the frontal position. The distance between the ankles may also be made use of in the examination as well as considera tion of the angle of the knee base (Mikuliez). In all cases the exact frontal adjustment of the axis of the knee-joint is most important because the real condition of the case may be concealed on account of rotation at the hip-joint.
Anatomically the deformity pertains to the lower part of the dia physis of the femur as well as the upper part of the diaphysis of the tibia. The epiphyseal line takes an oblique course, giving the internal coudyle, which rests upon it, the appearance of being much more elongated than the external. The upper end of the tibial diaphysis presents the same deformed condition, and in some eases to such an extent that it may be claimed as the main cause of the deformity (W. Blanchard). Since Albert's investigation we are accustomed, at least in all pronounced cases, to find changes involving the whole of both extremities. All weak parts become deformed, following the course of the assumed faulty attitude. To the obliquity of the epiphyseal line must be added a notice able enlargement of the internal eondyle, which undergoes a dispro portionate strain and thickening at this point as a result of the rarefac tion and a diminution of the external condyle.
With maximal flexion the elevation of the internal condyle is distinctly noticeable and there are also an abnormal laxity and a slight overextension of the capsular ligaments (Lange).
Etiology.—,The affection, in the first place, proves to be the result of the inability of the bones to respond to the difficulties of equilibrium which the body must overcome at the time of assuming the erect posi tion (posture of young children with feet wide apart which calls for a great horizontally acting component whenever the legs are held in such oblique attitude). Secondly, it results in an increase in the strain on the bones which are not yet properly fortified. The body yields at the very point where weight becomes a most critical factor (genu valgum of children) or where eventually remnants of curvatures of a former period exist (static germ valgum adoleseentium).
Symptoms.—Genu valgum is most frequently observed in small children. About 50 per cent. of all children present such deformities during the first stages of locomotion, Measurement of the distance between the ankles is possible in the recumbent position, and as a rule one leg is more markedly deformed than the other. The deformity disappears when the knee is flexed, due to a decrease of the open angle by half, or because of a slipping backward of the tibia from the oblique condylcs (Lange). Standing a child on its fret decreases the valgus deformity. At the same time it is observed that the chill tries to turn its knees toward the front or the back to avoid their knocking against each other. In mild cases a backward torsion always takes place. The foot is turned inward, aided partly by a torsion of the Id') and partly by adduction of the foot (walking with feet turned ill).
Only when a case becomes more pronounced, i.c., when genii valgum combines with an analogous pen valgus, is an outward torsion favored.
In very severe cases adduction and supination of the foot reappear, often being the only help in the attempt to walk on the soles (pc:: vans compensatories, Luksch). (Figs. 99, 101.) The inward torsion is thus to be considered a natural correction and must never be corrected itself.