Congenital knee dislocation

　　1. Etiology

　　There are different opinions on the etiology of this disease, some believe that it is due to the regression of the quadriceps femoris or muscular dystrophy in the fetal stage; some believe that it is due to the abnormal position of the knee joint.

　　2. Pathogenesis

　　Patients with congenital knee dislocation often have limb epiphysis abnormal development, accompanied by contraction of the anterior joint capsule of the knee and quadriceps femoris; there may be maldevelopment or absence of the patella, fibrous change in the vastus lateralis muscle; the patella moves outward, the iliotibial band and vastus lateralis muscle gap thickens; the cruciate ligament of the knee becomes thinner or absent.

　　Convergent limb epiphysis abnormal development: mainly manifested as pain in the hip and knee joints, limited activity, difficulty in walking, and a gait with a swing. Shoulder joint movement is also limited. The ends of the bones are often large, and a few patients have joint flexion deformity or joint laxity. The hands become shorter, the fingers thicker, and the stature short. Due to the greater impact of this disease on the long bones of the limbs than on the spine, it is manifested as a certain degree of short-limbed dwarfism. In addition, there are also genu varum, genu valgum, unequal length of the two lower limbs, and spinal lordosis deformity.

　　Patients have hyperextension of the knee joint, limited flexion of the knee joint, tension of the quadriceps muscle in a contracture state, tension of the iliotibial band, patella often moves to the lateral side of the knee joint, the tibial plateau is located in front of the femur, showing semi-dislocation or complete dislocation.

　　1. Measures to prevent fetal malformation; avoid fever and colds in the early stages of pregnancy. Women who have had a high fever in the early stages of pregnancy may experience adverse effects on the development of the brain tissue of the child, manifested as low intelligence, poor learning and response ability. This low intelligence is irreversible. Of course, fetal malformation caused by high fever is also related to the sensitivity of pregnant women to high fever and other factors.

　　2. Measures to prevent fetal malformation; avoid close contact with cats and dogs. Few people know that infected cats are also a significant source of infectious diseases that can cause fetal malformation, and cat feces are the main route of transmission for this malignant infectious disease.

　　3. Measures to prevent fetal malformation; avoid women who wear heavy makeup every day. Surveys show that the incidence of fetal malformation in women who wear heavy makeup every day is 1.25 times higher than that of those who do not. The main adverse effects on the development of fetal malformation are toxic substances such as arsenic, lead, and mercury contained in cosmetics, which affect the normal development of the fetus. The second is that some components in cosmetics can produce aromatic amines with teratogenic effects after being exposed to ultraviolet light from the sun.

　　4. Measures to prevent fetal malformation; avoid emotional stress during pregnancy. Human emotions are controlled by the central nervous system and the endocrine system, and one of the endocrine hormones, adrenal cortical hormone, is closely related to changes in human emotions. When pregnant women are emotionally stressed, adrenal cortical hormones may hinder the integration of certain tissues of the embryo, and if this occurs during the first three months of pregnancy, it may cause fetal cleft lip or palate and other malformations.

　　5. Measures to prevent fetal malformation; avoid drinking alcohol. When pregnant women drink alcohol, alcohol can pass through the placenta to the developing embryo, causing severe harm to the fetus. This may result in a small head, extremely small ears and nose, and a thick upper lip.

　　6. Measures to prevent fetal malformation; avoid eating moldy foods. Experts point out that if pregnant women consume food contaminated with moldy substances (moldy food), mycotoxins can pass through the placenta to harm the fetus, causing chromosomal breakage in fetal cells.

　　X-ray manifestations of congenital knee dislocation

　　Maldevelopment of the medial and lateral condyles of the tibia and femur, patella displacement to the lateral side of the femoral condyle; on the lateral view, it can be seen that the tibia moves forward and upward towards the femur, and in severe cases, the tibiofemoral joint relationship loses its normal shape.

　　1. Foods to eat for congenital knee dislocation: It is advisable to enhance nutrition, consume more protein-rich foods such as fish, eggs, and soy products, and appropriately increase calcium intake. Drink plenty of water, and eat more vegetables and fruits such as green vegetables, celery, and bananas.

　　2. Best foods to avoid for congenital knee dislocation: Avoid spicy foods: such as chili, mustard, etc. Habits such as smoking and drinking should be戒除.

1. Conservative treatment is suitable for newborns and infants with mild dislocation or subluxation, which can be treated with braces or plaster, keeping the knee in a flexed position, and fixed for about 1 year. For children, bone traction can be used first to relax the contracted soft tissue, and then braces or plaster are used for fixation.

2. Surgical treatment

(1) Soft tissue release surgery:

①Indications: Suitable for children under 2 years old with mild disease.

②Surgical Method: Through an anterior medial incision, the quadriceps muscle, patella, and patellar ligament are exposed. The quadriceps tendon is extended in a 'Z' shape, the adhesions in the knee joint are cut, and the anterior joint capsule is incised to allow the knee joint to flex as much as 90°. Fixed with plaster for 8 weeks (Figure 2). If the joint shape is abnormal and the deformity cannot be corrected, and the activity is still limited after soft tissue release, simultaneous osteotomy of the distal femur or proximal tibia may be performed. The choice of osteotomy site depends on the severity of the deformity of the femur or tibia. Then, the position of the knee joint is maintained with a non-extended plaster or brace for at least 1 year.

(2) Curtis and Fisher surgery:

①Indications: This procedure is suitable for children over 3 years of age with complete knee dislocation.

②Surgical Method: From the upper part of the inner side of the thigh to the lesser trochanter of the femur, down to the rough tuberosity of the tibia, the anterior thigh muscles are exposed. The quadriceps muscle is extended in an inverted 'V' or 'Z' shape above the patella. The anterior joint capsule of the knee joint is incised horizontally and extended backward to the medial and lateral collateral ligaments, and the lateral part of the patellar ligament is released to move the patella to its normal position between the condyles. If the iliotibial band and collateral ligaments are tense, a 'Z' shaped extension surgery is also performed. The patella is restored to a normal state with the long axis of the femur as the standard, and the extended quadriceps muscle and others are sutured, keeping the knee in a flexed position of 30°, and fixed with a long leg cast. The cast is removed after 6 weeks, and combined active and passive exercises are started; weight-bearing can begin after 10 to 12 weeks; older children may need to use a brace for about 1 year (Figure 3).