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Symposium: The Papers Presented at The Hip Society Meeting 1998: The Classic

Trendelenburg's Test


Peltier, Leonard F. MD, PhD

Editor(s): Brand, Richard A. MD

Author Information
Clinical Orthopaedics and Related Research: October 1998 - Volume 355 - Issue - p 3-7
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Friedrich Trendelenburg (1844-1924)

Friedrich Trendelenburg (Fig 1) was born in Berlin, Germany, where his father was a professor of philosophy and his mother was a teacher. Instead of attending school, he was educated at home by his parents. When his family moved to Glasgow, Scotland, he continued his studies, and in 1863 began to study anatomy and embryology. Between 1864 and 1866 he studied medicine in various clinics, finally being granted his medical degree by the University of Berlin. Such an educational background was not unusual in those days and medical students commonly studied for various periods at different institutions. After serving the required period in the army as a military surgeon, Trendelenburg returned to Berlin and came under the influence of the greatest German surgeon of the period, Bernard Langenbeck. After what would be called a residency today, lasting from 1868 to 1874, Trendelenburg became a surgeon in an important Berlin hospital. A few years later he became the professor of surgery in Rostock, Germany. His academic career flourished and included later appointment to the chairs of surgery at the universities of Bonn and Leipzig. He was an important leader in German surgery during the last half of the nineteenth century. He was the founder of the German Society of Surgeons and became its president.

Fig 1
Fig 1:
Friedrich Trendelenburg. (Reprinted with permission from Nissen R, Wilson RL: History of Chest Surgery. Springfield, IL, Charles C. Thomas Publisher 85, 1960.

Trendelenburg was a practical surgeon of wide experience. He popularized what has become known as the Trendelenburg position as an aid to performing pelvic and lower abdominal procedures. He raised the possibility of surgically removing pulmonary emboli of large blood clots, although he never performed the operation itself. The classic article reproduced here describing the gait of patients with congenital dislocations of the hip was written while Trendelenburg was in Bonn and shows his keen powers of observation accompanied by a thorough knowledge of the kinetics of normal locomotion. He died of carcinoma of the mandible.

Leonard F. Peltier, MD, PhD

Our knowledge of the anatomical conditions in congenital dislocation of the hip has recently been greatly increased, and has to some extent reached finality as a result of findings at operation. On the other hand the physiological question, as important in practice as it is theoretically interesting, of how the peculiar gait associated with this affection is produced, has not yet been answered; indeed, it has never been properly studied.

Both earlier and more recent authors say only that the cause of the swaying gait is caused by the abnormally mobile femoral head sliding up the ilium when the foot is put down-Dupuytren's "glissement vertical". A few mention the lordosis of the spine as a contributory cause, and all repeat the old comparison of the swinging gait to the waddle of a duck, which, to some extent, describes this type of gait, but does not explain it.

This idea that the abnormal mobility of the head of the femur across the ilium is the cause of the waddling gait is so firmly rooted that the first attempts at surgical treatment did not aim at reduction of the dislocation, but only at fixing the head of the femur to the pelvis (König), and operations of this kind are, even now, performed at times.

If the gait is carefully observed in naked patients it is soon realised that this view is not correct.

A child or, better, an adolescent or adult girl with bilateral congenital dislocation of the hip is told to walk alternately away and towards us. What do we see? Let us look first at the upper part of the body. At every step it swings to and fro, and it does, in fact, fall at each step to the side on which the weight is carried. If the right foot is put down while the left is raised the upper part of the body leans to the right and vice versa. If we call the side of the body with the foot down the standing side and that with the leg swinging the swinging side, the body thus always swings to the standing side. This fact seems to fit the idea that the head of the femur, sliding up when the foot is put down, is the cause of the swaying.

But now let us watch the pelvis. This also sways, in such a way that the right and left sides alternately fall and rise. The pelvis swings on a horizontal axis running from front to back in the sagittal plane at about the level of the first sacral vertebra. But the swing is not in the same direction as the movements of the upper part of the body, but opposite to them. If the right foot is put down, it is not the right anterior superior spine in front and the right buttock at the back which sink, but the left. In other words the pelvis does not, like the upper part of the body, sink on the standing side, but sinks on the swinging side. Now if the swinging movement of the pelvis were caused by the pelvis sliding down past the insufficiently fixed head of the femur the pelvis would sink, like the upper part of the body, on the standing side, and not on the swinging side.

It is precisely the opposing swings of the upper part of the body and the pelvis which is characteristic and peculiar in this gait, as the observer will now realise. He may also remember having seen this gait in only one affection other than bilateral dislocation of the hip, that is, progressive muscular atrophy.

The opposing swings meet between the sacrum and the lumbar spine: this is the pivot of the movements. It looks almost as if a hinge were inserted here, about which the spine moves in relation to the sacrum, and these hinging movements are prompt and full in a way hardly possible in the normal body. The joint has evidently become adapted to the increased demands, and we must expect to find corresponding anatomical changes in older patients. In fact, such changes have already been observed at autopsies, and they will certainly be found more often if they are looked for. In a man of 74 years with bilateral dislocation Dupuytren found at autopsy "a very unusual mobility in the lumbo-sacral joint, so that when the lower extremities and the pelvis were fixed the spine could easily be moved to and fro. Laxity of the intervertebral cartilage was the only recognisable cause of this remarkable mobility"; and Adams found, in a youth of 17 years, with unilateral dislocation that "the intervertebral substance between the last lumbar vertebra and the sacrum was much thicker than usual."

There is another way of demonstrating that the swinging movements are not due to the head of the femur sliding on the ilium. If the patient is told to walk past, or if one walks alongside her and carefully watches the relation of the trochanter to the edge of the pelvis, or feels it with the fingers, it is exceptional to find any distinct rise in the trochanter on putting down the foot; generally this symptom is indefinite, and often it is entirely absent, but the swing still occurs on walking. Movements of up to 2 inches, such as Froriep claims to have seen, do not occur at all in my experience. Even when the patient is lying down and the legs are pulled down, it is very easy to be deceived about the degree of mobility of the head of the femur upwards and downwards.

Moreover, if one compares the gait in various cases of bilateral dislocation, it soon becomes evident that the degree of swinging depends not on the firmer or looser attachment of the head of the femur to the pelvis, but on the position taken by the dislocated head, whether it is fixed or slightly mobile. The higher and further back the head is shifted from the normal place, or in other words, the higher it is and the greater the lordosis, the greater will be the swing. I would mention in passing that the displacement is by no means always proportional to the duration of the affection or to the age of the patient. One sometimes sees adults in whom the trochanters are only two fingers' breadth above the Roser-Nélaton line, and children of four years in whom they have wandered nearly up to the crest of the ilium. The generally made statement that the use of a boot with a raised heel in unilateral dislocation increases the displacement of the head is also, in my opinion, incorrect. At every step the leg must carry the whole weight of the body whether it rests on a high or on a low heel. Children with bilateral dislocation never wear high heels, yet it is particularly in them that a high degree of displacement often occurs very early. Anatomical conditions in the dislocated joint, and not the shape of the shoe, are therefore the deciding factor in the degree of displacement. However, the heel should not be raised enough to compensate wholly for the shortening of the leg for an entirely different reason, namely, to avoid forcing the dislocated joint into adduction, which easily leads to complicating contractures of the adductors.

Now how are these peculiar swinging movements produced? The answer need only deal with the swinging of the pelvis, since it is obvious that the movements of the spine in the opposite direction are only compensatory, and that they perform the task of bringing the centre of gravity, which shifts sideways, back to a point vertically over the standing foot, or, in short, restoring balance.

Let us observe first the gait of a normal person and ascertain in detail how it differs from that in dislocation of the hip. If we make a naked person stand with his back to us behind a plumb line, and make him walk a few steps away from us, we see that the whole body leans alternately a little to the right and left, and always to the side of the foot on the ground. The broader the base of the gait is, the greater the swing, and the more the gait approaches the military slow march, in which each foot is placed as nearly straight in front of the other as possible, the less the swing. The body forms a whole, the pelvis does not swing, but moves evenly forward without swaying. These to and fro movements of the body can easily be fixed photographically without the use of Anschütz's complicated procedure by making the subject examined stand behind a plumb line and raise first one leg and then the other. (I owe Dr. Perthes, Assistant in the Clinic, my special thanks for his help and advice in the sometimes tedious photographic work preliminary to this study). The first glance shows that the swing of the body occurs in order to bring the centre of gravity vertically above the point of support, i.e. the sole of the standing foot. The fact that the pelvis remains horizontal and does not drop on the side of the swinging leg is due to the action of the abductors of the hip joint, the gluteus medius, the gluteus minimus and partly the gluteus maximus. In the standing leg they are stiffly contracted, in the swinging leg they are relaxed. It is easy to ascertain in oneself that this is true in real walking, by putting the hands on the region of the gluteus medius while walking. The alternating play of the muscles can then be felt distinctly.

Let us compare this with a girl with bilateral dislocation; this girl had to support herself slightly with her hands in order to stand quite still. The difference leaps to the eye. The pelvis hangs down on the swinging side, and the upper part of the body leans far over to the standing side to restore balance. Figure 2

Figure 2
Figure 2:
Trendelenburg's Sign

From what has been said, the cause of the pelvis hanging down can only be that the abductors of the standing leg cannot keep the pelvis horizontal, because, as a result of the anatomical changes resulting from dislocation, they are incapable of holding it. The gluteus medius is reduced to about a third of the normal size, and the direction of its fibres is so altered that it cannot act at all as an abductor. Its anterior part is directed obliquely from the back at the top to the front below, the middle part is horizontal and the posterior part, which alone runs in something like the right direction, is so extremely shortened that its power of traction must be nil. It goes without saying that the action of the gluteus minimus is also completely destroyed, so the whole muscular apparatus providing for abduction of the hips fails.

It is rare to find a child with congenital dislocation who has enough power of abduction to raise the dislocated leg (in extension) against gravity when lying on one side.

Since paying attention to this point, I have never seen a child with unilateral dislocation able, when standing on the dislocated leg, to raise the buttock on the other side to the same level as that on the standing side, or even higher, which the same child can easily do when standing on the sound leg, nor have I seen a child with bilateral dislocation able to perform this test standing on either leg. The buttock or the pelvis on the swinging side always hangs down. An intact gluteus medius is essential to develop the relatively great power needed.

Other factors besides the abnormal directions of the fibres and the abnormal shortness of the muscle may contribute to the impairment of its power. When the neck of the femur has disappeared the muscle works on a shorter lever, that is, in more unfavourable conditions, and when the head of the femur remains movable in relation to the ilium the muscle is slackened because its points of insertion come closer together when the foot is put down; it is then too long for the system of levers, and must use part of its power to return to the state in which it can begin to exert an abductor effect. To this extent it must be admitted that the "glissement vertical" contributes indirectly to the swaying gait, though in a quite different way from that hitherto assumed.

If, therefore, the cause of the swaying gait is the absence of active abduction it is easy to understand the similarity of this gait with that in progressive muscular atrophy. In this disease the articular apparatus is intact and the gluteus medius and gluteus minimus have their normal length, but, as in bilateral dislocation, the pelvis is strongly tilted forward as a result of muscular weakness, and there is a corresponding lordosis of the spine. The direction of the fibres of both muscles is therefore more oblique than, normally and, even more important, the muscles can only act very incompletely because of the peculiar degeneration. For this reason, the pelvis cannot be held up by the abductors of the hip joint on the standing side and falls towards the swinging side, and the upper part of the body swings in compensation to the other side.

Very defective or entirely absent function of the gluteus medius and gluteus minimus, with the consequent lack of active abduction at the hip, is the cause of the waddling gait in congenital dislocation of the hip.

After treatment the two tests described above-standing on the treated leg and raising the buttock of the other side up to or above the horizontal line and raising the treated leg from the bed while lying on the opposite side-are a good measure of what has been gained by the operation, and the result can also be recorded photographically in this way.

© 1998 Lippincott Williams & Wilkins, Inc.