What Is Arthrogryposis Multiplex Congenita?

Congenital multiple joint contracture is a syndrome characterized by stiffness of multiple joints throughout the body due to fibrosis of muscles, joint capsules, and ligaments.

Congenital multiple joint spasm

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Congenital multiple joint contracture is a syndrome characterized by stiffness of multiple joints throughout the body due to fibrosis of muscles, joint capsules, and ligaments.

Chinese name

Congenital multiple joint spasm

the reason

Fibrosis of muscle, joint capsule and ligaments

which performed

Multiple joint stiffness throughout the body

Pathogenesis

Fetal limbs lose mobility in uterus

It is generally believed that the loss of fetal limb movement in the womb is the basic pathogenesis of the disease. It has been proven that many factors, such as the injection of certain drugs during pregnancy, and viral infections, can cause fetal limbs to lose motor function and suffer from the disease. Drachman has injected the poison of the arrow poison into the blood vessels of the chorioallantoic allantoin to create an animal model of polyarticular contracture. Moessinger injected the poison into the rat's uterus with arrow poison, and it also produced multiple joint contractures in the rat, pulmonary dysplasia, small jaw and short umbilical cord. Jago reported a mother who had a muscle relaxant due to tetanus when she was 10 to 12 weeks pregnant and gave birth to a baby with multiple joint contractures. Some viruses, such as Newcastle virus, Akabane virus and Coxsackie virus, have been proved to be pathogenic to this disease in animal experiments. ?

Pathologically can be divided into two completely different pathological changes of nerve type and muscle type. In neuropathic pathological changes, the disappearance, degeneration, or reduction of cell volume of bone marrow anterior horn cells are the most important features. There are also pathological changes such as the narrowing of the spinal cord of the neck and lumbar spine and the reduction of the number of anterior roots of the spinal nerve. The spinal dorsal, lateral, or dorsal root ganglion cells were normal. Brain damage includes hypoplasia of the brain, incomplete sulcus formation, enlargement of the lateral ventricle, and reduction of cortical Betz cells. The severity of these neurological lesions determines the pathological changes of the limb muscles that dominate. The volume, color, and texture of the limb muscles can be completely normal, or the volume can be reduced or even completely disappeared. It can be seen under the microscope that the number of muscle fibers is small and the diameter of the muscle fibers is reduced, but the stripes are more retained. Articular cartilage can be completely normal in the early stage, and articular cartilage destruction and degenerative changes occur in older children. The affected muscle type was free of primary spinal anterior horn lesions and abnormalities of the brain and neuromotor branches. The affected muscles are gray in color, hard in texture and fibrous. Under the microscope, the affected muscles exhibited fibrous and fatty degeneration, coarse and fine muscle fibers were randomly distributed, and the intramuscular fiber component increased. The pathological changes of articular cartilage and joint capsule are similar to those of neuropathy.

The clinical manifestations of this disease are very complicated. Hall classified the disease into three major categories according to the extent of the disease. The first type involves only the joints of the extremities, accounting for about 50%; the second type is joint contracture with visceral and head and face deformities; the third type is joint contracture with nervous system abnormalities. ?

The first type: two subtypes of muscular dysplasia and distal joint contracture. The former is a typical joint contracture. Usually after the patient is born, symmetrical stiffness of the limbs can be found, more rigid in the flexed position, or rigid in the extended position, but most of the last few degrees of flexion or extension activities are retained. The muscles of the affected limbs are obviously atrophic and there are cylindrical changes in the knee and elbow joints. Because the normal skin texture disappeared, the skin was shiny and tense, and the patient had a puppet-like appearance. When the joint contractures in the flexed position, the skin and subcutaneous tissue can form web-like deformities. The skin feels normal, but the deep tendon reflexes often weaken or disappear. Although all limbs can be affected, 46% of all limbs are involved, 43% of both lower limbs are involved, and only 11% of upper limbs are involved. When the lower limb is affected, the foot is usually varus and varus deformity, knee flexion or straightening, hip flexion-external rotation, abduction, or hip flexion-adduction contracture with dislocation. And 20% of patients have advanced C-shaped scoliosis. Upper limb deformities include shoulder internal rotation, elbow flexion or straightening, radial head dislocation, forearm pronation, and wrist flexion contractures. The thumb is more adducted and flexed closer to the palm with proximal interphalangeal joint flexion contracture.

The distal contracture type only affects the hands and feet. The thumb flexes and adducts across the palm. The other four fingers flex in a fist shape and the fingers overlap each other. Foot deformity is more common with plantar flexion and varus. It can also be heel deformity and is accompanied by toe flexion and contracture.

The second type: in addition to joint contractures, there are deformities in other parts, such as Marfan syndrome, Freemam-Sheldon syndrome, and pterygium syndrome.

The third type: joint contracture with severe neurological abnormalities, such as triploid 18, 9, 8, cerebral malformations, meningocele, etc., usually autosomal abnormalities, which can be diagnosed by peripheral blood karyotype examination, but Most babies die early.

Those with typical signs, such as atrophy of limb muscles, symmetrical contracture of joints, and normal skin feel easy to make a diagnosis. However, the distal limb contracture type, the hand and foot deformities are usually more slowly aggravated, especially those who are late for consultation, need to be distinguished from rheumatoid arthritis and congenital bone and joint deformities. However, hand-foot deformities in this type of patients are mostly symmetrically distributed, which is the characteristic of this disease. Secondly, laboratory inspections often found no abnormalities.

The treatment of this disease faces many difficulties, because the affected joints require multiple operations. The postoperative recurrence rate is high, requiring repeated surgery. However, the IQ of children is higher than that of ordinary children. After effective treatment, they can obtain amazing self-care ability. Therefore, physicians and parents should build confidence. The goal of treatment is to increase the range of motion of affected joints so that children can walk independently or assist them. It is possible to improve the operation of upper limbs and hands. Therefore, the following principles must be followed in treatment: Early release of soft tissue, incision or removal of some obstacle Joint movement of the joint capsule, ligaments, and contracted muscles can enable affected joints to obtain a range of motor functions. Because contractile soft tissue is more rigid and tough, physical treatments such as passive stretching and manual massage are not only ineffective, but also cause joint cartilage to become necrotic due to increased pressure. Although physical therapy has no corrective effect, it is based on soft tissue release. Adhering to physical therapy can maintain the effect of surgical release and delay the period of recurrence; fixation of the brace has a certain auxiliary effect, wearing at night is beneficial to maintain the position of surgical correction, wearing during the day can assist walking; due to the disease has The tendency of recurrence after surgery, so the use of muscle-tendon shift, to replace some of the muscles that have been fibrotic or weak, can obtain muscle balance, thereby improving limb function. However, its effect is worse than that of similar surgery for polio.

Under the guidance of these principles, the surgical method should be selected according to the specific deformity, deformity, and age of each patient. Horseshoe varus and valgus foot are common foot deformities in this disease and require early surgical treatment. Children are usually treated surgically within 3 months, and fixed with plaster to stretch tight skin before surgery. During the operation, the contracted joint capsule and ligaments should be removed. For horseshoe varus deformity, the talus should be completely loosened around and the heel talus joint should be centrally reduced. If the lateral column of the foot affects the reduction, the anterior part of the calcaneus can be removed (Lichtblau operation) or the calcaneal joint can be removed (Evans operation). Although stiff after operation, the foot can walk with the weight. If incision and reduction are encountered in the treatment of varus valgus, the scaphoid can be removed, and the talus and the 1st to 3rd wedge bones can easily form a ball and socket joint, and can also prevent ischemic necrosis of the talus. Knee flexion contractures are common, and mild flexion (<20 °) does not affect function. Can be fixed with night braces to prevent it from increasing with age. Patients with moderate knee flexion (20 ° ~ 60 °) should be treated with early surgery, mainly by cutting the posterior joint capsule and prolonging the hamstring muscles at the same time. If lateral collateral ligament and anterior cruciate ligament contractions prevent knee joint straightening, these ligaments can be extended for young children. Elderly children should undergo osteotomy of the femoral condyle. If the knee flexion deformity exceeds 60 °, the loosening of soft tissue can easily cause sciatic nerve and iliac arteriovenous injury, which requires bone shortening and osteotomy. The other option is anterior diaphragmatic stagnation of the distal femur and proximal tibia, but the results are not satisfactory. Knee joint straightening deformity is relatively rare, and it can be fixed by manual pulling and brace during the neonatal period. If the baby has reached 6 months and the manual stretching is still uncorrected, quadricepsplasty can be used to obtain satisfactory results. Long-term fixation of the brace at night can reduce the recurrence rate. Hip joint deformities are more complicated and can be divided into: 1. hip deformities with dislocation and 2. hip deformities without dislocation. Hip dislocation can be unilateral or bilateral. If dislocation of both hips and joint stiffness, it is not appropriate to treat. Because surgical treatment is prone to non-dislocation or subluxational rigidity of both hips, its function is worse than that of bilateral hip dislocation with stiffness. For single hip dislocation with stiffness, combined soft tissue release, open reduction and combined femoral shortening and osteotomy can improve hip function. If the dislocation of both hips is not accompanied by stiffness, they should be surgically released and resected open. Postoperative fixation with abduction brace for 3 to 6 months. Those with no dislocation of the hip joint may have the following deformities: abduction, external rotation-flexion deformity; simple abduction deformity; simple straightening deformity; simple flexion deformity. Among them, hip abduction, external rotation and flexion deformity are the most common. Unilateral ones often easily cause scoliosis, and bilateral ones have awkward gait. Hip tibial release can be adopted, and the broad fascia tensors and iliopsoas are cut or extended . Abduction deformities are rare, and the gluteal musculature and gluteal fascia are loosened by surgery. Simple hip flexion deformity is more common, but it is often not serious. Braces can be selected for treatment or prone sleep to correct it. In severe cases, hip flexion muscles need to be loosened by surgery. Simple hip straightening deformity is very rare, and can be used to loosen the structures of gluteal muscle, posterior fascia and ligaments.

Upper-extremity joint contractures are common with deformities of the elbow, wrist, and fingers. The elbow flexion and contraction of the biceps brachii and radial brachialis tend to retain certain functions, but the triceps brachii is weak, and the flexion joint capsule and ligaments thicken and contract. The lighter person is treated with passive traction and elbow extension plaster fixation, and the brace is used to maintain orthopedic effect at night. For severe elbow flexure contractures, surgery should be used to release and extend the biceps and brachialis muscles. Postoperative braces are still needed to prevent recurrence. Elbow extension contractures are more complicated, often with forearm pronation, wrist flexion, and finger deformities. His triceps muscles are strong, while his biceps muscles are weakened or completely absent. Passive traction and gypsum orthopedics can not only correct elbow extension deformity, but also cause joint cartilage necrosis and intra-articular adhesions to increase elbow stiffness. Because elbow extension deformity has a great impact on the upper limb function of children, such as eating, defecation and other daily activities, so surgery is needed. Surgical methods include extension of the triceps tendon, release of the posterior joint capsule and ligaments of the elbow joint, and displacement of the triceps and pectoralis major muscles to reconstruct elbow flexion. The extension of the triceps tendon and the release of the posterior elbow joint capsule and ligament can significantly increase elbow flexion. However, due to the weakness of the elbow flexor muscle, it is easy to relapse after surgery. Therefore, after the patient is 5 years old, when he can cooperate with functional training, he should choose triceps brachii, pectoralis major muscle displacement, and reconstruct elbow flexion function. In some cases, if you need to walk or use a wheelchair, the elbow extension is more conducive to complete the above-mentioned actions. After the elbow flexion function is reconstructed, a certain degree of elbow flexion deformity will be generated. Therefore, if both elbows have elbow extension deformity and need to use crutches or a wheelchair, only one elbow can be reconstructed. Flexion and contracture of the wrist joint is not only common but also more severe (up to 90 °) and accompanied by ulnar deformity. Correcting this deformity can significantly improve the function of the upper limbs, so the sooner the better. Some people even advocate that a few days after the baby is born, they will begin to passively pull and fix the cast, and at the same time correct the deformity of the thumb and other fingers. If the wrist flexion contracture is more fixed, a series of plaster orthopedics will be needed, and good results will be obtained. However, those with weakened extensor muscles of the wrist are prone to recurrence. The ulnar carpi flexor muscle can be selected at an early stage to rebuild the function of the extensor wrist. Williams advocates the use of intramedullary nails to stabilize the wrist joint after the age of 6, The third metacarpal and the distal radius were fixed with an intramedullary nail at a position of 5 ° flexion of the palm of the wrist, and the intramedullary nail was retained until the bones matured, and the wrist joint was wedged and fixed with plaster to fuse. Tachdjian used a dorsal wedge osteotomy at the distal radius of the ulna to treat severe wrist flexion and stiffness, which can correct deformities and prolong the flexion of the muscles and soft tissues of the wrist. Pronator contracture of the forearm, choose to cut the pronator round muscle, or replace the function of the pronator round muscle, can be satisfactorily corrected, the thumb adduction flexion deformity often includes the longus extensor, short hallucis and external Dysplasia or absence of abductor muscles results in contractures of the thumb adductor, the soft tissue of the tiger's mouth, and common finger and interphalangeal joints, which severely hinders the thumb-to-palm and grasping functions. Infant can adopt passive traction and brace fixation. Early childhood application of tiger mouth shaping, truncation of the adductor of the thumb adductor, elongation of the extensor hallucis longus or tendon displacement can improve thumb function. Finger flexion and contracture are common but not serious. Passive traction and night brace fixation are adopted early to prevent it from aggravating with age. In severe cases, the superficial flexor digitorus and collateral ligament should be released and fixed with fine Kirschner wires for three weeks. If the dorsiflexion of the fingers is often improved, but wrist flexion deformity occurs, the forearm segmental incision should be extended to extend the muscles and tendons of the deep flexor and superficialis flexors. Postoperative fixation with plaster or braces, especially long-term night braces, can prevent recurrence or prolong the interval between recurrences.