Brief introduction of knee joint deformity

Directory 1 Pinyin 2 Introduction 3 Congenital Dislocation of Knee Joint 4 Congenital Flexion of Knee Joint 5 Multiple Patella Malformations 6 Patella Absence 1 Pinyin X and gu ā n Jí e j and xí ng

Knee joint deformities are rare, including congenital dislocation of knee joint, knee flexion and patellar deformities.

Congenital dislocation of knee joint is characterized by unilateral or bilateral knee hyperextension 10 ~ 30 after birth, and even the calf folds to the front of thigh. The articular surface of the upper tibia moved to the front of the lower femur, and the quadriceps femoris tendon and iliotibial tract shortened. The knee joint can't bend, and the patella is smaller than normal or can't see clearly. After the dislocation of the knee joint was corrected, the patella could be seen again. The anterior joint capsule of knee joint is contracture, while the posterior joint capsule and anterior cruciate ligament are elongated and relaxed. This disease is rare and can be divided into two types: ① developmental disorder type: caused by fetal abnormality in uterus or fatty degeneration of quadriceps femoris muscle fiber. ② Primary embryo deletion type: often accompanied by other congenital developmental disorders, such as cleft lip or deformed foot. The first one is more common.

Repeated manipulations and plaster fixation gradually bend the knee joint. Those who fail need percutaneous iliotibial tract amputation and support. Stubborn cases need quadriceps femoris lengthening. If necessary, the patellar ligament, iliotibial tract, anterior joint capsule and posterior cruciate ligament should be loosened or lengthened, and the posterior joint capsule and anterior cruciate ligament should be folded and stitched tightly.

4 Congenital knee flexion Congenital knee flexion is also called knee hyperextension deformity. Can be divided into two categories: simple type and fixed type.

Simple knee flexion is mostly bilateral deformity, and knee extension function is normal. The sick child found the joint hyperextension after walking. Most people can heal themselves after the age of 3. Sick children are often accompanied by joint relaxation. X-ray examination showed no abnormality. Most babies don't need treatment. Those who still have unstable knee joints or complain of pain behind their knees at school age can be treated by supraankle osteotomy.

Fixed knee flexion refers to a serious situation, that is, knee hyperextension and knee flexion are limited to some extent after birth. Unilateral disease is more common, often complicated with congenital hip or foot deformity. In the most serious cases, the knee joint can be subluxated forward. The front of the knee is empty, with skin stripes, and the protruding femoral condyle can be felt behind the knee. You can feel the taut quadriceps when you bend your knees. X-ray film shows that femoral condyle is opposite to tibial articular surface, which can be distinguished from congenital dislocation and subluxation of knee joint. If this disease is not treated, the joint capsule and ligament of the knee joint will have secondary changes, and the flexor can move forward to play the role of extensor. Those who bend their knees more than 50 degrees can be corrected by manipulation and continuous plaster casting. If flexion is obviously limited, the quadriceps femoris should be extended as soon as possible before secondary changes occur.

5 Children with patellar ossification and patellar malformation are 3 ~ 5 years old and gradually develop and increase. Occasionally, the patella has two or more ossification centers. If this kind of polycentric patella is not fused normally, it can form double patella, triple patella or multiple patella deformity.

X-ray shows that there are more double patellas, that is, there is a small patella above the big patella. The two patellas are closely connected to form a complete patella shape. The difference between this deformity and patella fracture is as follows: ① The deformity is mostly bilateral. ② The running direction of the dividing line between patella and patella is downward and outward. ③ The contralateral edge is flat and dense, and the cortical structure of bone can be seen.

There are generally no obvious symptoms. The axial X-ray film of knee joint shows that the articular surface of double patella is not smooth, and knee joint pain often occurs in clinic. Persistent symptoms: removing a small piece from two patellas can relieve symptoms.

The absence of patella is a rare deformity. 70% were bilateral loss or contralateral patellar atrophy. Some sick children are accompanied by deformed feet or dislocation of hip joint. Individual cases are complicated with nail-patella syndrome, and nails also have extensive symmetry abnormalities and hypoplasia. The quadriceps femoris muscular atrophy or heterotopia in children with congenital patella deficiency stops in the knee joint capsule and skin.

The front of the sick child's knee is flat, especially after bending. If the quadriceps femoris develops normally, the knee joint function is acceptable, otherwise the knee extension force is weak, and knee joint flexion deformity may occur with the growth and development.

Sometimes it is difficult to distinguish between X-ray manifestations and delayed ossification of patella. Because the ossification center of patella appears after 2 ~ 3 years old, the diagnosis of this disease cannot be made before 3 ~ 4 years old.