In congenital dislocation of the hip also it may be said that better methods of treatment in recent years have brought with them a better outlook. Medical gymnastics and massage have also come into favour in the treatment of this disease in quite another way than formerly. Formerly medical gymnastics and massage were used quite frequently in treatment of congenital dislocation of the hip, but then this treatment proved itself as little effective as the treatment by leather apparatus and other pelvic girdles also frequently used, so that it eventually fell into disuse, and those children who were born into the world with this serious defect were too often left to their fate as entirely incurable.

A survey of the nature and special symptoms which make this defect so unsightly, the increased lordosis with the consequent backward-protruding pelvis, and, above all, the particularly ugly waddling gait, especially in double-sided cases, shows clearly that medical gymnastics and massage cannot have any curative influence upon this defect. The waddling gait, which with great injustice to the ducks is called duck-walk, is caused by the head of the femur having lost its support against the pelvis in the acetabulum, from the upper part of which, the so-called roof, the bone receives a firm support in a normal hip joint. If this support is absent the walk will be waddling, because the abductors of the hip, which are absolutely necessary for a steady gait, are not able to function. In order that a muscle shall be able to function, i.e., to exercise its intended effect upon two levers, it is necessary that its attachments, the origin and insertion, shall not lie too near each other (for a muscle can then only shorten itself a certain proportion of its length), also that the two levers are connected by such a joint that they are not able to move in any way against each other in that plane in which the angle of movement, in this case abduction, takes place. Neither of these conditions is fulfilled in congenital dislocation of the hip. The head of the femur lies in a somewhat movable position against the ilium above and behind the position for the joint cavity. The abductors, which every time the opposite leg is raised from the ground must fix the pelvis and so the whole trunk, are not able to do this on account of the too short distance between their origin and insertion, especially as this distance is further shortened by the upward movement of the head on the ilium when the whole weight of the body is thrown on the one leg. The opposite side of the pelvis therefore sinks, and, in order that the whole trunk, and with it the centre of gravity of the body, shall not move so far beyond the supporting area that the inevitable fall should result, the patient carries the upper part of the trunk back towards the supported side, thus causing the typical waddling gait. Even this ugly walk in the long run causes so much strain of the abductors, working in such disadvantageous conditions, that fatigue very soon arises, even to the point of inability to continue walking. The older and heavier the patient becomes, the more difficult are these mechanical conditions, and the defect progresses rapidly. As, moreover, the firm support of the femur against the ilium, so intermittent when walking, plays a very important part in the normal growth of bone, the patient becomes quite dwarfed both in growth and power as age progresses. In unilateral cases the waddling gait is less noticeable, but the marked and troublesome limp appears later. The increased lordosis and consequent prominence of the pelvis backward are the result of the fixed point of the pelvis on the femur being moved backward.

That massage and gymnastic treatment in these cases should be able to exercise any curative effect is obviously impossible. All that exclusive gymnastic therapy can do is to work up the abductors to the greatest possible efficiency'; in this way, at least for a short time, the waddling gait should become somewhat firmer and fatigue somewhat diminished. On account of the existing unfavourable mechanical conditions, however, this improvement can be only of short duration. And it is clear that the only rational treatment for this disease is, as with every other luxation, to replace the joint. This is generally with children much easier than reduction of a traumatic luxation of the hip, but the method has not yet given any result, because it has not been possible to maintain the restored position, so that relapse occurs as soon as the patient again begins to use his leg. This is accounted for by the poor development of the acetabulum, especially its roof, in these cases. It is only during the last few years that we have been able to maintain the reduction by means of improved methods of plaster. Sometimes, though not often, an open operation is used in order to obtain and maintain the reduced position. By means of these methods and their universal use the treatment of congenital dislocation of the hip has made very great headway. And one may say, with regard to the result, that the majority of single and a large number of double cases, presupposing the treatment to have begun early, which is an indispensable condition, have been definitely reduced by skilful treatment. Experience, however, shows that function, even after an anatomical reduction, is very poor, and when the patient after treatment begins to use the legs and walk it is practically unaltered. The patient waddles nearly as much as before. This is because the patient only learns by practice to correct his walk and other movements in accordance with the entirely altered mechanical conditions. With practice his walk becomes more certain and natural. The patient obtains the best possible function very considerably quicker if this practice is directed scientifically, and massage and gymnastic treatment are used as early as possible. The medical gymnast is therefore an important factor in the treatment. It is, however, extremely important that this should be given correctly, and that the gymnast is clear as to what he is expected to do. We have seen an example of a gymnast who was given such a case of reduced dislocation of the hip for after-treatment, and who indefatigably began to "work up" the joint, stiff after a long fixation in a plaster bandage. Nothing, however, is worse, and by such treatment a good result of reduction may be spoilt and even entirely done away with. As it is so extremely difficult to maintain the position of the head of the femur in the badly-developed joint cavity, it is quite clear that extensive passive movements may easily destroy the slight connection between the two bones. This especially applies to adduction and flexion, which are therefore absolutely forbidden. On the other hand, active exercise of the extensors, and especially of the abductors, is indicated, and for this purpose suitable exercises form the chief part of the treatment. The practice of abduction is performed first with the patient in side-lying position with abduction of the leg, in the beginning without, later with, resistance; the practice of extension in prone-lying position. Abduction practice in standing position is also important, especially in the form of practice in walking and standing. The patient must practise standing without dropping the opposite side of the pelvis, and this by degrees will become possible with the improved mechanical conditions under which the abductors now work. Further, the patient must practise walking without waddling, which is the same exercise. In this way a good walk is soon produced which sometimes may become quite normal; in other cases some waddling remains, but there is much more firmness than before reduction. That the functions cannot always be quite worked up to normal depends on the fact that the head and neck of the femur are often considerably deformed in congenital dislocation of the hip, and sometimes present a high degree of coxa vara, which also produces a certain amount of waddling gait, since in this deformity also the origin and insertion of the abductors approach one another beyond the normal distance, so that their efficiency is diminished.

Also in the treatment of these cases the medical gymnastic treatment plays a greater and more effective part than was formerly thought possible if carried out with full insight into the indications present.