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Lower extremity shortening

Introduction
Cause
Examine
Diagnosis

Introduction

Introduction Lower limb shortening: dislocation of the affected femoral head to the upper and lower parts of the common lower limb shortening is one of the clinical symptoms of congenital dislocation of the hip and hip dysplasia. There are many theories that explain the causes of congenital dislocation of the hip such as mechanical factors, endocrine-induced joint relaxation, primary acetabular dysplasia, and genetic factors. The mechanical stress of abnormal hip flexion during breech presentation can lead to posterior dislocation of the femoral head.

Cause

Cause

There are many theories that explain the causes of congenital dislocation of the hip such as mechanical factors, endocrine-induced joint relaxation, primary acetabular dysplasia, and genetic factors. The mechanical stress of abnormal hip flexion during breech presentation can lead to posterior dislocation of the femoral head. Ligament relaxation has been considered as an important pathogenic factor. The increase of estrogen secretion in the mother during the late pregnancy will facilitate the pelvic relaxation and the corresponding relaxation of the fetal ligament in the uterus. The femoral head dislocation is more likely to occur in the neonatal period. However, it is difficult to explain the cause of the disease by a single factor. It is generally believed that genetic and primary germplasm defects may play an important role in the onset. The hip joint of the fetus begins to be a fissure of interstitial cartilage, first in a deep concave shape, then It gradually becomes lighter and semi-circular. At birth, the tibia, ischium and pubis are only partially fused, and the acetabular fossa is extremely shallow. Therefore, the fetal hip joint has a large range of motion during delivery to make the fetus easy to pass through the birth canal. Therefore, the fetus is most prone to hips during the period before and after birth. Dislocation of the joint If the lower extremity of the fetus is placed in a straight position, the femoral head is not easily placed in the depth of the acetabulum and is easily dislocated.

Examine

an examination

Related inspection

Bone and joint MRI

Clinical manifestation

(1) Performance of newborns and infancy:

1 Symptoms: A. Joint movement disorder: The affected limb often has a flexed activity, which is more restricted than the healthy side. B. Short-distance of the affected limb: the dislocation of the affected femoral head to the posterior superior part of the femoral head is common. C. Changes in dermatoglyphics and perineum: The skin of the buttocks and the inner thighs is asymmetrical. The affected side is deeper than the healthy side, and the number increases the asymmetry of the labia majora.

2 examination: A. Ortolani test and Barlow test: for congenital dislocation of the hip from birth to 3 months first proposed by Ortolani in 1935, the method of improving Ortolani by Barlow is to treat the child with two knees and two When the hip is bent to 90°, the thumb is placed on the inner thigh of the child's thigh, and the middle finger is placed on the greater trochanter to gradually abduct and externally rotate the thigh. If there is dislocation, the femoral head can be felt in the acetabular rim and a slight abduction resistance can be generated. Then the trochanter is lifted upwards with the index finger middle finger. The thumb can feel the bullet when the femoral head slides into the acetabulum, which is the Ortolani test positive. The Barlow test is opposite to the Ortolani test. The examiner causes the patient's thigh to passively adduct the internal rotation and pushes the thumb outward to push the femur.

B. Allis sign (Galezzi sign): the newborn is lying flat and knees 85 ° ~ 90 ° legs together, double heel alignment, if the disease can be seen between the two knees. This is caused by the upward movement of the affected femur. C. Nesting test: The child's hip and knee joints are flexed 90°, and the examiner holds the distal end of the femur and the other hand in the hand to press the groin, and feels when lifting the knee of the affected limb. The large rotor is then moved up and down to be positive for the nesting test. D. Hip and knee flexion abduction test: the baby in the test is supine, the hip and knee flexion checker holds the knee in both hands, and the thumb is on the inner side of the knee. The remaining four fingers are normal on the outside of the knee. If the abduction is only 50° to 60°, it is positive and can only be abducted by 40° to 50°.

(2) Early childhood performance:

1 Symptoms: A. Minhang gait: Minhang is often the only complaint of parents when a child visits. When one side dislocated, it showed lameness; when bilateral dislocation, it showed "duck step", and the child's buttocks showed obvious posterior lumbar lordosis. B. Short-term deformity of the affected limb: in addition to shortening, there is also an adductal deformity.

2 check: A.Nelaton line: The anterior superior iliac spine and the ischial tuberosity are normally connected through the apex of the greater trochanter, called the Nelaton line. When the hip joint is dislocated, the greater trochanter is above this line. B.Trende lenburg test: Children stand on one leg and bend the other leg as far as possible to bend the hip and bend the knee to make the foot rise from the opposite side when the foot is standing normally. The pelvic decline is particularly clear from the back, and the positive test called the Trende lenburg test is a sign of hip instability.

2. Classification

(1) According to the relationship between the femoral head and the acetabulum: generally can be divided into the following three types:

1 congenital dysplasia: the femoral head only moves slightly outward, the Shenton line is basically normal but the CE angle can be reduced, the acetabulum becomes shallow, and Dunn calls this a congenital dislocation of the hip.

2 congenital subluxation: the femoral head is displaced outwards, but still forms joints with the lateral part of the acetabulum, the Shenton line is discontinuous, the CE angle is less than 20°, and the acetabular shallow is Dunn classification II.

3 congenital complete dislocation: the femoral head is completely outside the true acetabulum, forming a joint with the lateral aspect of the humerus, gradually forming a false acetabulum, the original joint capsule is embedded in the femoral head and the tibia is a Dunn classification III.

(2) Classification according to the degree of dislocation:

1I degree dislocation: the femoral head nucleus is located below the Y line and outside the upper rim of the acetabulum.

2 degree II dislocation: the femoral head nucleus lies between the parallel line of the upper edge of the y-line and the y-line.

3III degree dislocation: the femoral head nucleus is located at the height of the parallel line of the upper edge of the iliac crest.

4IV degree dislocation: the femoral head nucleus is located above the parallel line of the upper edge of the iliac crest and has false sputum formation.

Diagnosis

Differential diagnosis

To distinguish from the emptiness of the anterior humerus, the same is the dislocation of the humerus. In a few patients, the knee joint exhibits elastic flexion deformity, anterior temporal sensation, and the tibia can be touched and dislocated on the lateral side of the knee joint.