Deformities after polio arise due to residual paralysis that weakens the limb after an acute attack of polio. The medical term for this is post polio residual paralysis. Weakened muscle strength, imbalance of the forces acting on a joint and unequal growth of affected and unaffected muscles results in limb length inequalities and joint deformities, muscle and fascial contracture.
As polio may affect any region, there are a plethora of deformities after polio that may occur in combination/alone.
Fortunately, the polio is on the verge of eradication except for few countries.
But we still come across the patients with post-polio residual paralysis or PPRP.
How Does Muscle Weakness Occur?
Muscle weakness results from the destruction of the nerve cells in the anterior horn which results in degeneration of the peripheral nerve. As the peripheral nerve degenerates, the muscle supplied by it atrophy. Therefore weakness in poliomyelitis is a kind of lower motor neuron injury.
The extent of muscle degeneration depends on the amount of nerve involved.
On dissection, atrophied muscle fibers are recognized by their yellowish- white color. There could be a fatty deposit around the atrophied muscle. Tendons atrophy from disuse and lose their normal glistening appearance. Bones are also involved in the pathological process they are more attenuated than normal with a considerable degree of osteoporosis.
Shortening invariably occurs in paralytic limbs. The reduction of the blood supply from paralyzed muscles is probably an important factor. Joint capsules and ligament when not protected by healthy muscles become stretched.
The joints become unduly mobile and occasionally may dislocate if not protected. The skin circulation of the paralyzed limb is affected and responds more readily to local temperatures.
Once paralyzed, the recovery of individual muscle power may not show a significant increase after 18 months though some functional improvement may continue.
Aim of Treatment in Residual Disease
- To correct soft tissue contracture,
- To improve function
- Prevent deformity by tendon transfer and stabilization procedures, and
- To correct inequality of leg length
The exact approach varies with the person and the type of muscles affected.
For sake of ease, I am going to discuss the deformities and condition, region wise. The subject is vast and I am going to stick to the basics.
Paralytic Dislocation of the Hip
Paralytic dislocation of the hip is particularly common either acutely or slowly and indeed can be unnoticed. It follows flexion deformity, especially when associated with adduction. The relaxation of the joint capsule facilitates dislocation. The dislocation may be incomplete, giving rise to what is known as a ‘snapping’ hip.
Surgeries for paralytic dislocation include Shelf operation where a bone shelf is created by turning a piece of the ilium.
Arthrodesis of the hip is carried if other treatments fail.
Fixed Pelvic Obliquity
A true, fixed pelvic obliquity is when the pelvis is held in a fixed oblique position by contractures, which may be above or below the pelvis or both.
It could be
- Infrapelvic, due to fixed contractures of soft tissues involving one or both femoral pelvic articulations
- Suprapelvic, due to fixed contractures at the spinal junction
- Intrapelvic when there is hypoplasia of one or both hemipelves.
The treatment of severe deformities is surgical. For suprapelvic obliquity, correction of the scoliosis is desirable.
For infrapelvic fixed obliquity of the pelvis, the femoral intertrochanteric osteotomy is done.
Hip Flexion Contracture
This results from contracture of the tensor latae, the iliopsoas, the Sartorius and the rectus femoris. It is frequently associated with adduction of the hip, flexion deformity of the knee and talipes equines of the foot.
In severe cases and in cases which resist stretching, Soutter’s open division and fasciotomy are performed which involves stripping of hip flexors subperiosteally from their origin on the ilium and allowed to slip down the side of the pelvis. This permits of full extension of the hip.
It is often combined with Yount’s operation [described later]
Paralysis of Gluteus Maximus
Paralysis of the gluteus maximus leads to increased lumbar and backward lurch on walking.
Ober’s operation is done in paralysis of gluteus maximus which involves the transfer of tensor fascia lata by dividing fascia lata, to insertion of gluteus maximus.
In Dickson’s operation, the origin of the tensor fascia latae is transplanted with a piece of its bony attachment to a groove on the crest of the ilium near the posterior superior spine, the muscle thus being changed from an abductor and flexor or an abductor and extensor.
Paralysis of the Gluteus Medius Muscle
Gluteus muscle is hip abductor and on its paralysis, when the weight is borne on the affected side, the patient lurches over to that side.
Gluteus medius limp may occasionally be improved by posterior transference of the tensor fascia lata [Legg’s operation] when some residual power remains in the glutei but results are uncertain.
Mustard operation involves the transfer of iliopsoas tendon to act as the hip abductor in the presence of a normal gluteus maximus and of a normal Sartorius muscle.
Contracture of the iliotibial band
Contracture and paralysis of tensor fasciae latae are intrinsically bound up with the similar disease of the gluteus medius and minimus, and it only acts as a stabilizer of the pelvis in flexion and not in the abduction.
Established contracture of the iliotibial band will not respond to conservative measures.
Early contractures may be satisfactorily corrected by the division of the iliotibial band [Yount’s operation]. In this surgery, the iliotibial band is divided about 2.5 cm proximal to the patella. A 5 cm section is excised.
Flexion Deformity of Knee
Flexion knee deformity occurs when there is a weakness of the anterior thigh muscles. There is strong overaction of the posterior group. The deformity can be prevented and corrected by the use of Thomas’s knee splint. Other non-operative methods of reduction of the deformity are wedge plasters, reversed dynamic traction.
Surgical correction is done by tendon lengthening of the semimembranosus, semitendinosus, gracilis, sartorius biceps and tensor fasciae latae.
Mild deformities usually are well tolerated. Severe deformities require corrective osteotomy.
Genu recurvatum signifies excessive extension at the knee. If there is adequate muscle power in hip flexors, the gluteus maximus, and the hamstrings, the biceps femoris transfer to weakened quadriceps could provide good results.
For mild deformities, bracing can be done. Femoral flexion osteotomy could be considered for severe deformities.
For all kind of deformities, knee arthrodesis may be considered if the deformity is not corrected by other methods.
Leg and ankle Deformities
Contracture of the Tendoachilles
It may occur from overaction of the calf muscles unopposed by paralyzed extensors.
In severe cases, the tendocalcaneus may have to be lengthened by open operation and the posterior capsule of the ankle joint divided it contracted.
It must be noted that the patient with weak quadriceps use equines of the foot to back-knee for stability in stance and in these patients, lengthening of tendoachilles may cause worsening of the gait.
Lateral Rotation Deformities of the Leg
Lateral rotation deformities of the leg are commonly seen due to the muscular imbalance around the knee and ankle joints when either flexion or equines contractures develop. Corrective osteotomy may be done in selected cases.
Plantar Fascia Contracture
Persistent contracture of the plantar fascia produces a cavus or cavo—adducted foot. Steindler stripping operation gives a satisfactory result. In this surgery, the plantar fascia is divided close to the calcaneus. After this, the foot is manipulated for correction and immobilized in plaster.
Deformities of the foot
Foot deformities are treated by tendon transfers and bony procedure. The idea is to create a balance in opposing muscles so that recurrence of deformity can be avoided, or corrected with improvement in function. Following things should be kept in mind
- The imbalance between invertors and evertors should always be achieved
- The opposing action tibialis anterior and peroneus longus should be kept in mind. Tibialis anterior elevates the base of the first metatarsal and supinates the base of the forefoot, while peroneus longus depresses the base of the first metatarsal and pronates the foot.
This is resulted by paralysis of the tibialis muscles. The calcaneum everts and no longer supports the head of the talus, which inclines medially and downwards with depression of the longitudinal arch.
Following procedures are used for this deformity
- Strut graft stabilization of the talocalcaneal joint
- Peroneus brevis transfer to the medial cuneiform.
- In the presence of overactivity of the peroneus longus with the cocking of the big toe, the tendon of extensor hallucis longus can be transplanted to the first metatarsal and the interphalangeal joint of the hallux is fused.
- In long-standing deformities where passive correction of the subtalar joint is not possible, triple arthrodesis is done.
This is due to the paralysis of the peroneal muscles. The foot becomes inverted due to the action of the tibialis anterior and posterior.
This deformity is due to isolated paralysis of the gastrocnemius. Active dorsiflexors plus active peronei and tibialis posterior muscles produce a progressive calcaneocavus deformity despite caliper protection.
In the young child, the deformity may be minimized by transplantation of the tibialis posterior and peroneal tendons into the heel cord, followed by protection with a caliper.
In the older child, transplantation of tendons into the heel cord should be accompanied by triple arthrodesis.
Paralysis drop- foot is satisfactorily controlled by a caliper with a toe-raising spring or a dorsiflexion spring at the ankle. Lambrinudi foot fusion with transplantation of overacting peronei to the dorsum of the foot is reserved for the older patient.
Claw Toe Deformity of the Hallux
This is hyperextension deformity of the first metatarsophalangeal joint, which occur on attempted dorsiflexion of the foot is caused by uncoordinated contraction of the extensor hallucis when the tibialis anterior is paralyzed.
Claw toe deformity occurring in a foot with adequate dorsiflexion power is satisfactorily treated by interphalangeal fusion of the hallux.
Transference of the extensor hallucis tendon to the neck of the first metatarsal accompanied by interphalangeal fusion of the hallux is a satisfactory procedure when the power of dorsiflexion of the foot is only slightly impaired.
Different Stabilizing Surgeries of the Foot
Stabilizing operations consist of the fusion of different joints of foot and/or osteotomies.
Foot fusion operations should be postponed until the age of 10—12 unless deformities is too severe to press for an early fusion.
Different Stabilizing Procedures of the Foot are
Extra articular arthrodesis of the subtalar joint [Grice]
This involves the reduction and maintenance of the calcaneus in a normal relationship the sinus by means of strut bone grafts placed in the sinus tarsi. Muscle balance is restored by tendon transplantation to avoid recurrence.
Fusion of the subtalar and midtarsal joints is indicated when deformity or instability of the foot is accompanied by the lateral stability of the talus in the ankle mortise. Varus or vagus deformities are corrected by excising appropriate wedges of bone from the midtarsal and subtalar joints. Deformities such as knock-knee the tibial torsion should also be corrected at the site of deformity.
Naughton Nunn operation
In case of severe static deficiencies, it is desirable to secure forward displacement of the talus on the calcaneus. The operation combines a subtalar arthrodesis with a reconstructive shortening of the forefoot.
The foot is displayed backward at the subtalar joint so that the head of the talus will rest in a shaped depression prepared for it by the removal of bone from the dorsal surface of the cuneiform bones.
It is done in cases of paralysis of the foot dorsiflexor and peronei, but with some muscular control of the knee and preferably with active calf muscles. The aim of the operation is to use the anterior process of the talus to prevent dropping of the foot.
The wedge of the bone is removed from plantar distal part of the talus so that talus stays in equinus but the forefoot is repositioned to the desired degree of correction.
Paralysis of the deltoid with adequate power the scapulothoracic muscles should be treated by arthrodesis of the shoulder joint after the upper humeral epiphysis has closed. In the interval, unrestricted use of the arm is encouraged to maintain tone in the scapular muscles.
Provided function of the hand is satisfactory, all the efforts should be done to reconstruct the elbow for better function of the limb, especially the flexor function.
The procedures include
- Steindler’s operation of proximal transposition of the common flexor origin from the medial The best results are obtained when the brachioradialis is still functioning
- When biceps, brachialis, and brachioradialis are completely paralyzed but good power is present in the pectoralis major transposition of part of the pectoralis major to the biceps tendon can be done [Clark]
Loss of pronation of the forearm
Loss of Supination
- Some recovery expected in case of Clark’s transplantation of pectoralis major.
- Transposing the tendon of flexor carpi ulnaris around the ulna and inserting it into the radius just proximal to the wrist.
Wrist and Hand
Provided hand joints are supple, tendon transfers work very well in hand. If needed, wrist arthrodesis could be done. For small joints of hand in contracture, arthrodesis in functional position may be the best solution.
The most successful results in tendon transplantation are obtained when the wrist flexors are transferred to the finger extensors since they normally have a synergic action.
Complete Flexor Paralysis
Extensor carpi radialis longus and extensor carpi ulnaris may be transplanted to the tendon of flexor pollicis longus and to the deep flexor tendons of the fingers.
- Pronator teres transfer to the extensor carpi radialis longus and brevis.
- Flexor carpi radialis to the abductor pollicis longus and the extensor policis brevis.
- Palmaris longus to extensor pollicis longus.
- Flexor carpi ulnaris is inserted into the extensor digitorum tendons.
- Arthrodesis of the wrist will often release good hand function.
Loss of active opposition of the thumb
- Any tendency to web contracture should be overcome before an operation.
- Tendon transfers are able to correct the deficit
- Tendons of flexor pollicis longus, extensor digiti minimi or palmaris longus can be used.
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