Part 8

Braces (American system) for appliances of wood.

If the stump is short a combination of the two methods is best.

A. SUSPENSION BY MEANS OF A WAIST BELT.--For the peg leg made of leather the best method consists in placing a pelvic plate, which is attached to the hip steel, below the iliac crest (Figs. 20 to 24). A belt attached to the extremities of this plate surrounds the pelvis and passes above the iliac crest on the other side. The thigh piece is attached to this support, on the outer side, by articulation of the outer femoral steel with the hip steel; on the inner side, by a perineal strap. Braces complete the method of suspension of the apparatus (Fig. 21).

The axis of the metal joint between the outer femoral steel and the lower end of the T piece should be directly above the great trochanter (Fig. 20).

The femoral steel often breaks in the neighbourhood of this joint (Fig. 23); we have got over this difficulty by adding immediately beneath it a joint which allows of abduction (Fig. 19). A perineal strap limits this movement.

FIG. 23.

Suspension from the pelvis.

A metal hip piece is fixed below the iliac crest and held in place by a belt which passes above the iliac crest of the opposite side (Figs. 20 to 24). This piece is attached to the thigh bucket by a joint shown in figure 19 (see also Fig. 22), which allows both flexion and abduction of the hip, and which forms the suspension of the outer side of the limb. The inner border is suspended by means of a perineal strap, shown in figures 21 and 22. In figure 21 is shown how a suspending brace may be easily added. Figure 23 shows the action of a single hinge joint, allowing only flexion and extension at the hip joint. On page 27 will be seen similar joints which, however, move on the pelvic attachment as well as on the thigh piece. The object of this is to prevent the pinching of the abdominal wall by the top of the thigh bucket when the patient sits. It is indispensable in short stumps. On page 21 will be seen a joint which allows abduction of the hip, and thus relieves the strain upon the hinge joint; without it the latter is easily broken.]

B. SUSPENSION BY MEANS OF BRACES (American method).--The American method of suspension has the advantage of leaving the pelvis free; the patient does not feel the pull of the hip piece. Besides, when the belt is used, if the patient sits down, the buttock on the side of the stump is raised, to an extent corresponding to the thickness of the bucket, an obliquity of the pelvis, which is both uncomfortable and unsightly, being produced. The braces being relaxed in the sitting posture, the patient can avoid this inconvenience; for the stump may be slipped partly out of its bucket, the upper extremity of which is then beyond the level of the edge of the chair. This position is very comfortable, because it is normal, but the patient must replace his stump in the bucket whenever he stands up.

FIG. 25.

Braces composed of straps passing over the shoulders and down the front, attached to the bucket by buckles. Posteriorly they are joined together by a cross strap between the scapulæ, and beyond this are continued in the form of elastic straps.]

This form of suspension is essential for those artificial limbs with a free knee-joint, in which, as we shall see, the braces serve to extend the joint.

We illustrate here two methods of attaching the braces to the thigh piece, that which we use in the limb supplied by the Fédération (Figs. 24 and 25) and that which is used in the American limb of Marks (Figs. 26 and 27).

FIG. 27.

FIG. 26.--Braces which end below in looped thongs of leather.

FIG. 27.--These loops, held in to the thigh piece by passing beneath a loop of leather, pass over two pulleys about the middle of the inner and outer sides of the thigh piece respectively. The outer brace tends to abduct the limb if it is tightened.]

C. COMBINED METHOD OF SUSPENSION.--If the stump is short the artificial limb must be attached both by a belt and by braces; the latter should be 5 to 6 centimetres wide.

Combined suspension for short stumps.

FIG. 28.--Complete appliance.

FIG. 29 and 30 show the value of a flexion pivot between the hip piece and the pelvic plate. If there is no such pivot, the T piece undoubtedly rotates upon the belt, but not to a sufficient extent to prevent the thigh piece in rising and pinching the abdominal wall (Fig. 29). If there is a double joint the hip piece becomes oblique, thrusting the thigh piece forward and allowing the patient to sit erect (Fig. 30).]

In these cases also, to prevent the stump escaping from the bucket when the hip is flexed, the front of the thigh piece is carried as high as possible; but if the appliance is furnished with a metal T piece, such as has been described (Fig. 29, see also Fig. 23), then this raised border prevents flexion of the hip by coming in contact with the abdominal wall when the patient sits down. This difficulty can be got over by making the top of the T piece movable; when the patient sits down the vertical piece of the T becomes oblique, the thigh piece comes forward, allows the stump to escape a little way and no longer presses against the abdominal wall (Fig. 30).

The belt may also be replaced by a leather corselet, having fixed to it the hip piece that we have just described.

The braces by themselves are a poor method of attachment for a short stump.

In the sitting position the stump easily escapes from the bucket.

When the patient is standing the stump remains abducted, whilst the apparatus, as the result of its own weight hangs vertically, in this swaying position the lower extremity of the stump presses against the outer side of the bucket, whilst the inner edge of the bucket cuts into the flesh at the top of the thigh.

III. WALKING ON A PEG LEG AND SIMILAR APPLIANCES

The rigid peg and the jointed peg.--The peg leg is a rigid rod, ending in a slight enlargement, which transmits the weight of the body, resting by means of the ischium upon the top of the bucket, directly to the ground.

The erect position is thus very secure, and stability in walking is also very good throughout the time when the artificial limb bears the weight.