Hesperian Health Guides

How to Correct Contractures Using Plaster Casts

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HealthWiki > Disabled Village Children > Chapter 59: Correcting Joint Contractures > How to Correct Contractures Using Plaster Casts

The example we give here is for the knee, but the basic methods are the same for contractures in ankles, feet, elbows, and wrists.
Two adults cast leg of child lying down.
Correcting contractures with casts. (PROJIMO)

Casting the leg


1. Put stockinette or a close fitting cotton stocking on the leg. Avoid wrinkles. 3. To protect the knee, it helps to put a soft sponge or piece of sponge rubber over the knee.
Leg in cast with arrows pointing to features.
2. Put cast padding or cotton roll (or wild kapok) evenly around the leg. 4. Put extra padding around the thigh, the knee, and the ankle.
5. Put a plaster cast on the leg. Be sure it reaches high up the thigh. 7. Holding the calf below the knee, gently straighten the leg as far as it will go, without using force.
Leg in cast with two hands pulling up lower leg, and arrows indicating actions at the ankle, knee and top of leg.
6. Put lengthwise strips of plaster for reinforcement over the knee. 8. Position the foot at a right angle (or as near to it as you can without using force).


The cast is straightened a little every few days. In a small child or a person with recent contractures, it can be done every 2 or 3 days. In persons with old contractures, progress will be slower. To save on costs, change the cast every week or 10 days.


1. Cut through the plaster behind the knee. 2. Use steady, gentle pressure so that the leg straightens a little and the cut opens.
Bent leg in cast, of person laying face down, arrows point to front and back of knee.
Leg in a cast with wedge of cast removed from the back of the knee, two hands pushing downward to straighten leg.
3. Hold the cut open with a small wedge of wood. 4. Wrap a piece of cloth around the knee.
Leg in a cast with wedge of cast removed from the back of the knee, wood used to prop open cast behind knee. Slightly bent leg in cast, ring of cast around knee.

CAUTION! When stretching the leg, use gentle, steady pressure until it begins to hurt a little. Do not try to advance too fast, as you may cause permanent damage to nerves, tendons, or the joint.

For a day or so after stretching, the child may have some discomfort behind the knee. This is normal, unless it hurts too much. You can give aspirin. If the child complains of pain over pressure points or bony bumps, remove the cast or cut open a window in the cast to check if a sore is forming.

WARNING! When casting a child who does not feel in his limbs, take great caution to avoid pressure sores, and use very little pressure.


1. Cut and remove the ring of plaster. 2. Gently stretch the joint and put in a wider wedge.
Slightly bent leg in cast, cutting off ring of cast around knee. Slightly bent leg in cast with wedge of cast removed, wood to prop open cast.
3. And cover it with a new ring or plaster.
new plaster ring covering the further stretched joint.


bigger wedge , plaster leg cast with knee ring.
Each time you change the ring, put in a bigger wedge.


Continue casting until the knee is completely straight or bends backward just a little. Then use a brace for at least a few weeks (day and night) to keep it straight.
almost straight leg with wider wedge being put into the knee cut.


Straightened leg in cast with wood behind bandaged knee area.
The time to straighten a contracture may vary between 2 weeks and 6 months—or more. If the leg stops straightening for 3 or more cast changes, stop casting and try to arrange surgery.

Straightening a leg that is hard to stretch

In an older child who has a knee contracture with strong muscles that bend the knee, it may be hard to straighten the knee more with each cast change.
boy with one leg bent severely at the knee.
If the leg does not move when you pull it, ask the child to...
woman talking to boy while he sits and she pulls his leg straight.
Pull hard with your leg against my hand! Harder! Still harder! ...And now relax!
When he relaxes, keep pulling, and the leg should straighten a little.
boys leg straitening more while woman continues to pull
Repeat this several times while you steadily pull the leg. Each time the knee should straighten a little more.

Straightening a tiptoe contracture

A foot with a contracture like this, can sometimes be straightened with casts and wedges.
arrow pointing to ankle joint on foot with strong downward contracture resulting in a continuously pointed foot.
tight heel cord
casted foot with a cut from the heel almost to the top of the ankle.
Put lots of padding under the cast on top of the ankle.
Be sure the cut reaches fairly high up the ankle (not across the top of the foot).
Try to overcorrect the contracture so that it will rest easily at a (90°) right angle when the cast is removed.

casted foot with wedge where the ankle is bent so that there is less than 90 degrees between it and the shin
Do not let the child walk on the cast until the day after it is put on—and then only if you put a ‘walking heel’ on it. Otherwise the sole of the cast will become floppy and will not help. Active children need very thick plaster on the bottom of the foot.
casted foot with a wooden blocked strapped to the bottom.
wood or rubber walking heel

For the child who lives too far away to have her cast changed every few days, you can try to make an aid that will gradually pull the foot up without needing frequent cast changes. Here is one idea:

alternate foot cast with inner tube looped from toes to top of shin, the cast has a cut made on the top of the ankle down toward the heel.

strip of car inner tube
Bend the cast edges outward with pliers so they will not dig into skin as foot rises.
bump to keep inner tube from slipping
strong reinforcement of plaster
Put lots of padding under the heel.

CAUTION! lf the child is sent home with a cast be sure the family knows the danger signs. If any of these appear, have them quickly bring the child back or remove the cast themselves.

Danger signs:

  • constant, severe pain—especially in areas where pressure sores can occur
  • a darkening or change of color in the toes
  • numbness or burning
  • a smell like rotting meat (a late, very serious sign)
To take off the cast without tools, in an emergency, soak it in warm water and unwrap to tear it apart.

Note: This cast is not as strong as a fully covered one and will not last on a very active child. It will usually only work on a child without much sideways deformity of the foot or ankle. The cast may need to be changed 2 or 3 times as the foot straightens.

This page was updated:19 Jan 2018