HIP AND KNEE CONTRACTURES

It is essential that the patient is assessed in detail before any operative procedures are considered. The main criteria with any operation on the lower limb are whether the patient is likely to be able to walk with or without a caliper following an operative procedure, and whether the patient will be socially benefited by being able to walk. As a general guide line all children who have a reasonable chance of being able to walk post-operatively, even with difficulty and even with calipers on both legs, should have their limbs straightened, and every attempt made to get the child up and mobile. In the case of adults, operative procedures are only indicated where there is a good chance of reasonable mobility. The future employment and wishes of the patient should be taken into consideration, as well as age. As a general rule old patients with very severe deformities requiring extensive surgery should have a low priority on operative correction, while young patients and those with minimal deformities should be considered first.

CONTRAINDICATIONS TO OPERATION IN CHILDREN

1. Both legs severely involved with one or both arms, particularly the triceps, week. ie. the child will not be able to use crutches or walk in calipers. Good arms on both sides are important if both legs and the trunk are severely affected. There are notable exceptions to this rule and each child should be assessed as to the possibility of future walking if the contractures are straightened.

2. Minimal contracture of the hip alone of less than 3 In all other circumstances the child should be operated on if necessary and got upright and walking. The psychological effects of mobility on a child are tremendous, and parents will often educate and look after an upright child when they tend to neglect a crawling one.

CONTRAINDICATIONS TO OPERATION IN ADULTS

1. Where one or both arms are weak in addition to both legs being severely paralysed, i.e. the use of crutches will be difficult or impossible. Fairly strong arms, particularly the triceps, are important if the patient is to progress upright. Again, as in the case of children, a patient with determination may manage surprisingly well with limited weakness in one or both arms provided his trunk is strong.

2. When there is only a minimal degree of contracture and the patient is managing to walk well.

3. When there is severe contracture of both knees and the patient earns his livelihood on the ground and is happy to continue doing so.

4. Where operative facilities are poor and contractures severe.

In an adult with polio contractures it is essential to consider the patient as a whole and not only the contracture. An adult patient who can crawl fast on the ground and earn his own living is often better off than one who can only progress very slowly upright with stiff knees and two crutches. The latter may look better, and almost certainly feels better. He may have difficulty in planting crops in an agricultural community, which may be his only means of livelihood. He may therefore die of starvation and neglect following well-meaning operative intervention.

Serious consideration must be given to the future occupation and mobility before bilateral severe contractures are straightened. A simple wheelchair may be a far better method of progression for long distances, while pads on knees and hands may allow fast local progression, and mobility indoors.

Isolated hip contractures of less than 30°

No treatment is required for these when there are no other contractures. The stability of the hip is often improved, and shortening compensated for, if there is a small degree of abduction/flexion contracture.

Isolated knee contractures of less than 30°

In a child these are best treated by fortnightly manipulations under anaesthesia until at least 2° of genu recurvatum is obtained. An above knee caliper is then fitted. If there is associated hip contracture preliminary soft tissue correction will also be necessary. (see below). Russell traction will also correct this deformity but will take time and will necessitate hospitalisation. In adults this contracture may be much more difficult to correct. Manipulation alone usually fails. Russell traction again takes time but may be effective. In some adult patients with a mild degree of flexion deformity no treatment, however, is necessary. In others a supracondylar osteotomy may be indicated, but only if the foot is stable, and a caliper may thereby be discarded.

INDICATIONS FOR OPERATION

Hip and knee contractures of over 30°

These will all require operation, with the exceptions already mentioned. In a young child with fairly recent contractures the most important single factor responsible for the deformity is a tight tensor fascia lata and ilio-tibial band. In the older child or adult, however, other ligamentous and tendinous structures play an important part and must be divided as well. (See below). The subcutaneous method of division is very satisfactory for the less severe contractures, provided it is done correctly and as extensively as necessary. Care must be taken to avoid damaging the femoral and popliteal- arteries and the common peroneal nerve. The biceps, however, should always be divided under direct vision because of the risk of damaging the adjacent lateral popliteal nerve. The operative techniques employed are illustrated, and will also be described in detail

OPERATIVE DETAILS (Fig. 23(a))

Sterility and position on operation table

The operation must be done under full sterile precautions with adequate skin preparation and sterile towels. It is better to sterilise both legs even if only one is to be operated on, so that the opposite hip can be kept flexed to compensate for a lumbar lordosis. The affected hip and knee should be kept as straight as possible when the tight structures are being divided so that these are kept under tension.

First incision

This is situated on the lateral side of the thigh about 1 inch above the knee joint. The tensor fascia lata is kept under tension, and can usually be felt as a tight band. The knife is inserted horizontally from a lateral to a medial direction just behind the tight band, and directed towards the femoral shaft until the tip touches the lateral cortex of the bone. The blade is then twisted through 90° so that its sharp edge is pointing vertically anteriorly. All the subcutaneous structures anterior to the blade and lateral to the lateral surface of the femoral shaft are then cut. It is important that the tight structures be cut anteriorly enough, and that the relative positions of the popliteal artery and lateral popliteal nerve be borne constantly in mind. If the flexion contracture of the knee is more than 30° it is also essential that the biceps tendon is divided by open division under direct vision (see below). This will also enable the lateral intermuscular septum and the posterior part of the tensor fascia lata to be divided much more safely and efficiently than by the subcutaneous method alone.

Second and third incisions

These are situated one-third up the thigh and two-thirds up the thigh on the lateral aspect. One incision instead of these two, and situated in the middle of the thigh, would be adequate, however. The tensor fascia lata should be palpated and the knife should be inserted in the same way as in the first incision along its posterior border down to bone. It should then be twisted through 90° and the cut made anteriorly and lateral to the lateral border of the femoral shaft. If the tensor fascia lata is not palpated the knife should still be inserted into the lateral aspect of the thigh, as there will be other tight structures to be cut including the vastus lateralis.

Fourth incision

This is situated about one finger's breadth below the anterior superior iliac spine. The position of the femoral artery should be palpated and borne constantly in mind during the operation. The position of the inguinal ligament should also be noted and care taken not to divide it. The femoral nerves just lateral to the femoral artery are usually tight, but should not be divided. They usually protect the artery just medial to them. The blade of the knife is inserted subcutaneously below the anterior superior iliac spine and in a lateral to medial. direction, and slightly downwards, for about three-quarters of an inch. It is then twisted through 90° so that the blade is facing backwards and all the subcutaneous tight structures are cut.

If the hip contracture is severe all the tight structures lateral to the femoral nerves and right down to the front of the femoral neck and trochanter should be cut. It is important that the tip of the blade, when inserted deeply, should also be angled downwards so that the blade of the knife is parallel with the inguinal ligament. This will avoid the risk of cutting the ligament.

The anterior tight structures having been cut, the blade is then twisted so that it cuts laterally, and all the tight structures on the anterio-lateral side of the hip are cut. The blade should not go further back then the corona1 plane of the anterior part of the hip joint, and the abductors posterior to this are left intact to give stability to the hip.

The hip must-be kept in as much adduction and extension as possible while the tight structures are being divided. The tight structures should also be palpated through the skin at intervals during the operation to ensure that no tight deforming bands have been left undivided.

POST OPERATIVE TREATMENT (Fig. 23(b))

It is important that all blood clot is squeezed out periodically during the operation and at the end. This applies particularly to the hip incision which may bleed considerably. It is also essential that after the plaster has been applied, the hip incision be checked again, and any blood which might have reformed squeezed out with full sterile precautions. This incision should then have a small pad of wool with tight elastoplast strapping across it. The other incisions only require a plastic spray and a small gauze dressing.

Subcutaneous elongation of the tendo Achillis, if necessary, should be carried out after the hip and knee contractures have been divided. The leg or legs are then put in well padded above-knee plasters, or in Russell traction. Plaster is best used when the knee contractures after the first operation are less than 45 degrees or when shortage of hospital beds make outpatient treatment essential. Russell traction, however, is better for severe knee contractures, especially in older children and adults. It may entail a stay of 2 or 3 months or longer in hospital, but is less likely to lead to painful stiff knees and late osteoarthritis. If plaster is used the ankle should be firmly dorsiflexed. The knee, however, should not be put under any tension at all, otherwise pain and pressure on articular cartilage will result.

With plaster correction the hip and knee should be manipulated every two weeks until the knee is in at least 2 degrees of genu recurvatum and the hip has 10 degrees or less of flexion deformity. It is essential that the manipulation is done by the methods already discussed, and that at least five to ten minutes be spent on each individual joint.

Backward subluxation of the knee should be corrected or avoided, and lateral rotation of the tibia on the femur may also require correction. It is also essential for the knee to be fully flexed with each manipulation and for the tibia to be rotated both medially and laterally to maintain this very essential mobility. The leg should be put into a well padded above-knee plaster after each manipulation, but again the knee should not be under any tension. A walking piece is attached to the bottom of the plaster as soon as the flexion deformity is less than above 40 degrees, and the patient should be got up walking with the help of crutches.

The final plaster is left on for two weeks, and then replaced by an above-knee caliper. It is essential that the posterior knee strap of this caliper is loose, and that the patient wears his caliper day and night for the first two or three weeks until the liability for the flexion contracture of the knee to recur has diminished. It should then be worn during the day. If possible the patient should have physiotherapy or assisted exercises after the plaster has been removed.

The use of turnbuckles to straighten a severely contracted knee after operation, or wedged plasters to straighten slight contractures, is seldom indicated, although theoretically desirable. Knees become very painful and may sublux backwards, and stiffness is much more common than after correction by manipulation. Painful stiff knees often occur after prolonged correction of severe contractures.

Intensive physiotherapy and Russell traction may be required for severe intractable cases, and occasionally patellectomy or arthrodesis. It must be remembered that many knees which are painful and stiff after prolonged immobilisation in plaster regain some and often all their movement within a period of weeks or months after operative correction. Pain usually also disappears even in those patients who do not regain a full range of movement.

OTHER PROCEDURES FOR KNEE CONTRACTURES

Russell traction (Fig. 23(c))

Russell traction, if used alone post-operatively, for severe knee contractures, should be supplemented by daily passive stretching. Manipulation under anaesthesia in addition will not be necessary, except occasionally for the last 10 or 20 of a flexion contracture which may be difficult to correct, and may require plaster in addition. Alternatively this can be treated by continued traction with a weight of 2 or 3 lbs. attached to a sling over the lower half of the thigh. This will then pull the femur downwards while a sling under the calf will exert countertraction upwards. Russell traction will also in many cases correct some of the severe flexion contractures of the hip. An equinus deformity of the ankle, however, may recur during prolonged traction unless it is supported with a back slab. In addition the ankle should be passively stretched each day to maintain correction if it is contracted, or if an equinus deformity has been corrected.

Open biceps tenotomy (Fig. 23(d) )

The biceps tendon should be divided in all knee contractures of over 30 degrees. It must always be done by open operation because of the close proximity of the lateral popliteal nerve. The incision for this is shown in Fig. 23(d). The biceps tendon is easily palpated and found and can be quickly mobilised out of the wound by a pair of scissors inserted behind it to hook it out. It is important to make sure that it is indeed the biceps tendon, and only the biceps tendon, which is being divided, as the common peroneal nerve may resemble it closely. Muscle fibres should be identified actually being inserted into the tendon. In addition the division should be done with great care as the common peroneal nerve may sometimes be adherent to the back of the tendon. After division a finger should be placed in the wound to palpate any other tight structures.

The lateral intermuscular septum and the posterior part of the iliotibial band will often be found in need of division, and sometimes the most anterior part of the deep fascia lata as well.

CORRECTION OF OTHER DEFORMITIES

Genu recurvatum

In children this should be treated by an above knee caliper with a tight posterior strap if it is more than 10°. In adults it should be left untreated if it is not getting worse or causing complications. A corrective osteotomy is occasionally required.

Valgus deformity of the knee

This is common and seldom requires specific treatment in polio except for adjustment of a caliper to prevent it rubbing. In severe cases an additional valgus knee strap can be used.

Tibial rotation and backward and lateral subluxation of the tibial plateau

These are usually but not always associated with a flexion deformity of the knee. They should be corrected if possible at the same time as the knee deformity. Often these deformities are asymptomatic and alone do not require specific treatment.

Fractures

These are common in polio, and should be treated in the same way as fractures in patients without polio. The opportunity should be taken, however, to use the fracture to correct any existing deformity in the fractured limb.

Dislocation or subluxation of the hips

This is occasionally seen with severe paralysis of the hip muscles. It is more usual, however, after an extensive open division of the hip muscles and ligaments for a flexion deformity. Dislocations require reduction and treatment by an abduction spica. Some cases of recurrent dislocation are best left untreated. Others may require an osteotomy, an arthrodesis, or occasionally a psoas transfer.

SEVERE FLEXION DEFORMITY OF THE KNEE

This may be associated with backward and lateral subluxation of the tibia, and also with lateral rotation of the tibial plateau.

In children the subcutaneous methods of correction already described should be tried. In adults a painful stiff knee may often result, quite apart from the difficulty and time involved in straightening a severe longstanding contracture.

In adults with one deformed knee a compression arthrodesis (Fig. 23(g)) may be indicated in the patient with a stable ankle and minimal shortening. A supracondylar osteotomy (Fig. 23(e) & (f)), however, is better for the patient who will require a caliper for either a weak ankle or severe shortening.

In adults with both knees severely contracted, there is a definite indication for leaving the patient crawling if his only means of livelihood is from the cultivation of crops. It may be much more difficult, and occasionally impossible, for a patient with two stiff knees and weak hips to cultivate the land, especially if there is associated weakness of the spine. In some cases where a permanent job for the patient can be found in a factory or office, this may be a good indication for getting the patient walking, provided the arms are powerful enough to use crutches. In these cases bilateral supracondylar osteotomies, or an arthrodesis on one side and an osteotomy on the other side, is indicated.