When you have released a patient's contracture, the muscles of his leg will still be weak, so you will probably have to provide him with a brace, or a crutch, or both. A weak hip needs crutches, a weak knee needs a long caliper, and a weak ankle needs a short one. If you cannot provide him with calipers, don't try to release his contractures!
There are four types of orthopaedic appliances of increasing sophistication:
(1) Appliances of the traditional type, such as the pads, kneelers, sticks, peg legs and crutches, that are used in traditional societies everywhere. Unfortunately, there are no traditional calipers.
(2) Appliances of the Huckstep type, shown in Fig. 27-6. These can be made in a hospital workshop using locallly available iron, galvanized wire, wood, and leather, and can be repaired by a bicycle mechanic, a cobbler, or a blacksmith. If they are properly made with hardwood, a child will usually outgrow them, and need a larger size before they wear out. If they are made of soft wood they wear out quickly.
(3) Appliances of an intermediate type are more durable than Huckstep's. They are cheaper than appliances of type (4), and are less dependent on imported materials. An example is a modified Bata shoe with a metal tube to support the end of the iron bar. If these shoes have an open toe, they will fit feet of various sizes, but are less durable in wet weather. The leprosy shoes in Section 30.5 are of this kind.
(4) The expensive high-technology appliances that are standard in the industrial world. These need imported materials, particularly duralumin and special plastics, and can only be made and repaired by a skilled prosthetist. Unfortunately, many prosthetists consider it a matter professional pride to make only the most sophisticated appliances of this type, which patients cannot afford. Resist their efforts, and encourage them to make appropriate appliances in sufficient quantity.
If you cannot get ready-made appliances from an orthopaedic service, ask your hospital workshop to make those of Types (2) or (3). All large or medium-sized hospitals, doing much surgery, need a workshop making a wide range of appliances of level (3). You will need above- and below-knee calipers, fitted when necessary with backstops or frontstops. These differ only in length, in the diameter of the ring, and in the presence of a knee piece in an above-knee caliper. Calipers of Types (2) and (3) have irons each side of the leg. Although the single outside or inside irons of the calipers of Type (4) look more elegant, they are weaker, they are more difficult to make and adjust, and they are usually less effective than double ones.
Use calipers to prevent deformities in a weak limb, and to straighten and support a child's leg after you have corrected his contracture. There are few indications for fitting calipers on an uncorrected contracture. Fit them as soon as he starts to walk, and replace them with a larger size as he grows. Encourage all children, who have muscle weaknesses which might lead to deformities, to wear calipers until they have stopped growing, even if they can walk without them.
The indications for fitting an adult with a crutch, or a caliper, are the same as in a child, except that an adult has usually had polio many years ago in childhood, so that his deformities are now stable, in that he is unlikely to get new ones.
Fig. 27-5 PARALLEL BARS FOR POLIO are helpful when a child is learning to walk. Kindly contributed by Ronald Huckstep.
ORTHOPAEDIC APPLIANCES [s8]FOR POLIO ABOVE-KNEE CALIPER If you are uncertain if a knee or ankle caliper is going to be useful or not, consider applying a suitable plaster cast of the same function for 4 to 6 weeks. If it is helpful, make a caliper. In this way you will avoid making calipers that do not help.
INDICATIONS. Fit a child with an above-knee caliper if: (1) His knee is so weak that he is unable to lift his leg against gravity (the power in his quadriceps is [lt]3). If he can lift it against gravity, a caliper will not help him. (2) He is likely to develop a contracture as the result of muscle imbalance. (3) He has a mild knee contracture of less than 30[de] that a caliper could correct, if he wore one during the day or at night. (4) He is developing a hyperextended knee, as the result of trying to lock and stand on it. (5) He has weak quadriceps, and at the same time too much equinus to let him swing his leg, and lock his knee.
CONTRAINDICATIONS. Don't fit him with an above- or a below-knee caliper, or crutches, if: (1) He is able to walk reasonably well with a flail ankle[md]walking may be easier without them. (2) He is able to walk reasonably well with a weak knee. He may have learnt to use his hamstrings to extend his thigh, and lock his knee. (3) He needs crutches (because of weak hips), but does not have enough power in his triceps, shoulders, or trunk to use them. (4) You have not corrected his deformity (unless it is a very mild one, and the caliper is designed to correct it).
FITTING. Choose a caliper which reaches about 2 cm below his ischial tuberosity when he is standing, make the straps fairly tight, and make sure that the knee piece gives his knee adequate support anteriorly. Make the posterior strap slightly loose, unless his knee is abnormally hyperextended.
If he has a mild flexion deformity of his knee, fit him with an ordinary caliper with a loose posterior strap, and a tight knee piece, which may need to be padded.
If his knee is hyperextended (genu recurvatum), you can correct this easily, so apply only slight tension to the posterior strap.
If he has a valgus knee, bend the caliper to avoid his bony points, and fit him with an inner knee pad tied to the outer side of his calipers, to prevent his knee from rubbing against the inside iron, especially when he is bearing weight. Fit it so that it presses on the medial side of his knee, and corrects the deformity as he walks.
CAUTION ! A long caliper keeps a knee straight, and lets him walk. But, because his knee does not bend, it may become fixed in extension, and be a nuisance when he sits. So make quite sure that when he takes his caliper off, he puts his knee through a full range of passive flexion. This should not be a problem, if he takes off his caliper each night.
BELOW-KNEE CALIPERS [s7]FOR CHRONIC POLIO INDICATIONS. Provided there are no complications (see above), fit him with a below-knee caliper if his foot is flail or drooping, or is tending to go into varus or valgus, provided the power in his quadriceps is [mt]3. If it is [lt]3, he needs an above-knee caliper.
FITTING. Choose a caliper that will allow his knee to flex fully, with a socket which will fit firmly, and not allow too much movement. Always fit a supporting ankle strap.
If his calf muscles are so weak that his foot dorsiflexes excessively, fit him with a front stop.
If he has little power in his dorsiflexors, so that his foot goes into equinus, fit a backstop.
If his ankle is inverted or everted, fit the appropriate inner or outer T-strap.
FOLLOW UP. Try to see him at least every 6 months. Replace his caliper with a larger one as he grows. A long caliper is no use if it ends just above his knee! Make sure that his family understands that he will need a caliper for life. Do all you can to help him with his education.
OTHER APPLIANCES [s7]FOR CHRONIC POLIO CRUTCHES. You will need a variety of sizes. If possible, make them to measure. If necessary, you can use any straight stick with a handle and a bar for the axilla. He will find a crutch useful if polio has weakened his hips. Let him try one and see how he manages with it. His grip must be strong enough to hold it, his triceps must be strong enough to propel him forwards, and his spine must be strong enough to allow him to sit without help.
A crutch is likely to help him if: (1) Both his legs are in calipers. (2) One leg is in calipers, and his opposite leg or his spine are weak. (3) One leg is in a caliper and is very weak, and his hip on the same side is weak.
Fit crutches as in Section 77.1. The length and the position of the hand grip must be right. Many patients who are given crutches could manage equally well with a stick. It you try him with a stick, teach him to hold it on the opposite side to his weak or weakest leg. If his hands are too weak to hold ordinary crutches, he may be able to use forearm crutches.
CAUTION ! Make sure that he does not lean on his crutches, while they are in his axilla. He may paralyse his radial nerve, or even all the nerves to his forearm and hand, and they may take 6 months to recover.
A TOE SPRING may be of great help if he has foot drop. Fix a suitable spring, or a piece of bicycle tubing to the toe of his shoe and to a strap below his knee (30-5). Alternatively, fit a back stop, which is easier to fit.
AN ANKLE SPLINT will be useful if he is in danger of foot drop while he is in bed. Make a suitable splint from plaster, or padded boards, to keep his foot at 90[de] to his leg.
A RAISED SHOE will help him if one leg is [mt]4 cm shorter than the other. Any cobbler will raise it for him. If he has [lt]4 cm of shortening, do nothing (78.1).
Fig. 27-6 APPLIANCES FOR POLIO. A, calipers of the Huckstep type. Note that long leg calipers should reach to 2 cm below the groin. They will be useless if they only reach to just above the knee. B, a modified shoe, as an example of an appliance of Type 3. Kindly contributed by Ronald Huckstep.