BELOW KNEE DIAGRAMS

The most common leg amputation is below the knee. A leg that has been amputated halfway between the knee and ankle works best for walking with an artificial limb. Here are some examples of artificial limbs, from simple to more complex.

WITH THE KNEE BENT

CAUTION: Limbs like these 3 are quick and easy to make, but they   cause knee contractures. As a result, the knee cannot be easily straightened   to fit a better, more useful limb. Bent-knee limbs should only be for   temporary or emergency use. Do exercises every day to keep the knee   straight and strong. See also the "iWalk Free" manufactured version of this bent-knee, hands-free crutch at bottom of this page.

WITH THE KNEE STRAIGHT

BAMBOO AND PLASTER LEG

PLASTIC PIPE LEG WITH FOOT

These limbs are better because the knee has full range of motion. Walking   is easier and more natural. However, the person's weight must be supported   evenly over the entire stump, not only at the end of the stump.

Positions for FITTING A LIMB

From the time a leg has been amputated until a limb is fitted, daily exercises are needed to keep the hip and knee muscles strong and to avoid contractures. If weakness and contractures already exist, these should be corrected as much as possible before a limb is fitted.

NOTE: When the person is not wearing the artificial leg, he should also wear an elastic bandage to control the stump shape.

The art of limb making

Making artificial limbs that fit and work well is both a science and an art. If possible, try to learn from a skilled limb maker. 'On-the-job' training for even a few days can make a big difference.

Before starting to make an artificial limb, STUDY THE PERSON'S LEG

A good fit of the socket on the stump and at the knee is one of the most important - and difficult - parts of limb making. It helps to have an understanding of the bones and muscles in the leg.

Before beginning, study the person's knee and stump carefully. Note the positions of the kneecap, the bony bumps on the sides of the knee, and the shin bone.

MEASUREMENTS YOU MAY NEED FOR A   BELOW-KNEE LIMB    (Copy this chart and use it to record your measurements.)

Note: For the plaster and bamboo limb, only lengthwise   measurements are needed.

Note: The artificial limb should be the same length or just   a little shorter than the other leg.

PLASTER AND BAMBOO BELOW-KNEE ARTIFICIAL LEG

Steps for making the plaster socket

1. Make a thick 'cup' or 'cap' of sponge or folded cloth and tape it over the end of the stump (to give it a little extra length).

2. Put a thick, tight-fitting stocking -without seams if possible-over the stump and knee. (Several thin layers of stocking can be used instead of a thick one.)

3. Put a thin plastic bag over the stocking.

4. Put a thin cotton stocking or stockinette over the plastic bag and also pull tight to avoid wrinkles.

5. With the stocking stretched tight, mark the important places with a 'grease pencil'. The pencil marks will 'print' onto the inside of the plaster cast when it is removed.

Mark all these places:

Note: If you do not have a stocking, you can mold the socket   directly on the stump. Shave any hair off the stump and cover it with  vegetable oil (for example, coconut or palm oil).

6. Wrap the stump and knee with plaster bandage. Be very careful to put the bandage on evenly and smoothly. (Elastic plaster bandage works best, but is very costly. To reduce costs you can make your own plaster bandages for casting..

MAKING THE PLASTER   WATER-RESISTANT

The plaster cast of the stump will become the inner layer of the socket of   the bamboo limb. So it should be strong and waterproof. To make the cast   stronger and water-resistant, wet the plaster bandage with glue instead of   water.

Use a water-base   glue that is water-resistant when it dries.

Note: If the plaster cast is to be used only as a mold for making a   leather or resin socket, use water, not glue.

7. As the plaster dries, hold the stump firmly below the knee.

8. When the cast becomes hard, mark where to cut the top edge (see below).

9. To remove the cast, roll the stocking over it. Put your hands over the pressure points (as shown above). Have the patient  wiggle the stump as you gently pull off the cast.

10. Cut the cast along the line you drew.

Preparing the bamboo post

1. Select a piece of strong, green bamboo a little longer than the good leg from the knee to heel.

2. Split the bamboo to a little below the level of the stump end. Split into thin strips-each about 3/4 cm. wide.

3. Remove the softer inner layer from each of the thin strips.

4. Spread the bamboo strips around the plaster socket.

5. Position the socket as correctly as you can. Then with a thin wire, wrap the bamboo tightly against the socket.

6. Put the limb on the stump and have the child stand on it. Check the length. If necessary, cut some off the post.

Note: If patient uses a shoe or sandal, be sure to have him/her wear it when measuring the height of the limb.

7. After trimming the tops of the bamboo strips, cover the outside of the socket with several layers of glue, sawdust, and gauze bandage:

Brush on one layer of glue. Press sawdust on the glue (with gloves). Wrap tightly with gauze  bandage. Let it dry Repeat 5 or 6 times.

8. Smooth the outside of the socket with sandpaper. Also smooth and round the inner edges at the top.

9. Make a 'cuff' to hold the limb on. (if attached correctly, it should also help keep the knee from over-straightening.)

10. Make a rubber 'heel' - a piece of thick truck tire works well. If you can, cut the tire so that a 'plug' fits inside the bamboo. Cut off bamboo as much as the heel is thick. (Be sure to allow for height of sandal or shoe on other foot.)

Design   for the knee cuff

Use strong leather and line it on inside with soft smooth leather. It   should be a few cm. longer than the distance around the knee.

Glue layers of leather and webbing together with rubber cement and sew at  edges.

11. Have the patient stand and walk on the limb for several minutes. Then remove it and look for sore spots on the patient's skin, or signs of too much pressure. Check especially over bony spots. An area that looks pale when the limb is removed and then turns red or dark, is a sign of too much pressure.

12. Scrape shallow pits into the socket from the inside, at the points where it presses over bones. You may also need to build up around the area where pressure occurs.

During the first few weeks of using an artificial limb, the stump becomes  smaller, and several changes in limb size may be needed. To save time, use a  shorter bamboo post so that the plaster socket can be replaced several times  with new, smaller ones.

This is free information found on the internet, provided for your convenience. Search under "crutches" to find distributors.

The "iWalk Free" crutch is another option for below-knee amputees to use on a temporary basis, such as when they are getting their prosthesis repaired and want to be mobile. Bent-knee crutches, such as the "iWalk Free," should be used as a temporary crutch. Take it off as much as possible during the day and exercise your leg to keep your knee straight and strong. Don't wear it all day long because you don't want to develop a contracture of the knee, where it will be difficult to straighten it. Remember to always exercise, exercise, exercise. See also 'Sawed-Off Crutch' leg at the top of this page.

Excerpts from:

Disabled Village Children A guide for community health workers, rehabilitation workers, and families by David Werner

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