Knee inversion and knee valgus, which are quite common clinically, are one of the most common reasons for visits in children. Knee inversion and knee valgus are angular deformities based on the knee joint leaving the body or near the body relative to the longitudinal axis of the body, with the apex located at the knee joint, respectively. The presence of inversion and ectropion is not necessarily a disease that requires treatment, but can be classified as physiologic or pathologic depending on the cause. As the name implies, physiological knee inversion and knee valgus are a stage in the development of the body, which can be improved and corrected on its own as the body matures and does not require special medical intervention; pathological knee inversion and knee valgus are deformities of the internal and external knee joints caused by various reasons, including rickets, asymmetric epiphyseal injury, infection, congenital epiphyseal developmental deformity etc. As pathological knee valgus deformity, the deformity often increases with the aggravation of the primary lesion, which requires close clinical observation and, if necessary, surgical intervention.
For physiological knee valgus deformity, the authors reviewed a large amount of literature and found the following patterns in children’s knee valgus deformity: 1. For the cause of its appearance, more scholars believe that the embryo in utero due to abnormal fetal posture, resulting in developmental deformity. 2. In normal children, when the skeleton matures, the knee tilts out and the degree of valgus is close to the adult level, i.e. 8° in males and 7° in females. 4. 6. Physiologic internal and external knee valgus generally does not require medical intervention, but if the internal and external valgus is significant, it is often a pathologic change that requires further examination to clarify the cause.
Pathological internal and external knee deformity Etiology: including rickets from various causes, abnormal epiphyseal development, destruction of the epiphysis by inflammation or trauma, etc., local bone bridge formation, premature closure of the epiphysis, and excess of trace elements such as fluorosis.
Pathology: Depending on the cause of the disease, the primary site may have local abnormalities including local asymmetric premature closure of the epiphysis, destruction of the epiphysis, deformity of the knee internal and external rotation, disorder of the force line arrangement of the lower limb, and asymmetric negative focus of the epiphysis.
Clinical manifestations: The first is the change in appearance, which is manifested as an inversion deformity of the knee. Knee inversion deformity refers to the natural straightening of both lower limbs, the patella facing forward and the natural coming together of both feet, the medial side of both knees cannot come together, i.e. the distance between the two femoral inner condyles increases, and both lower limbs show O-shaped changes, also known as O-shaped legs. At the same time, when walking, the toes of both feet face inward, showing an external figure of eight. In some cases, the tibia is slightly bent inward and accompanied by internal rotation deformity. Due to the change in the line of force of both lower limbs, the center of gravity is shifted outward. On the other hand, the knee valgus deformity is characterized by an increase in the distance between the two inner ankles when the femoral condyles are brought together with natural extension of the lower extremities, resulting in an X-shaped change, also known as X-shaped leg. The child may have abnormal walking gait because of the collision and friction when walking on both knees. Due to muscle spasm, the child may have pain in the calf muscles.
Imaging: X-ray is the main test. X-rays are used to make a clear diagnosis and to understand the pathological causes of internal and external knee valgus. The angle between the longitudinal axis of the tibia and the femur, the tibiofemoral angle, can be measured to determine the degree of knee inversion and development. In internal derangement of the knee, the knee joint plane is slightly oblique, the upper tibia is angled, and there are generally no abnormal changes in the local bone cortex. Knee valgus is often seen as an angular change in the lower end of the femur.
Treatment and prognosis: 1. First, the treatment of the cause. This includes symptomatic treatment of various causes of rickets. If there is a bone bridge formation, surgery is also required to remove the bone bridge, etc.
2, brace fixation treatment. There are different reports on the efficacy of brace treatment. Some scholars believe that there is no significant improvement in the course of the disease and the rate of development. However, it is also believed that local bracing can improve the rate of disease progression.
Osteotomy treatment. If the internal and external knee deformity is still evident after treatment of the primary disease, when the skeleton is mature and the epiphysis is closed, surgical treatment is recommended. Specific indications are generally those with a bilateral ankle spacing or bilateral femoral medial condyle spacing greater than 10 cm. Internal derangement of the knee is usually treated by V-shaped osteotomy of the upper tibia. The specific osteotomy point is determined by calculation based on X-ray pictures. For a few deformities at the knee, osteotomy at the lower femur can also be performed, but with the addition of a physiological inward slope of 10° at the lower femur to take advantage of the complete restoration of the limb force line. In contrast, valgus knee deformity is treated with inversion osteotomy of the lower femur or V-shaped osteotomy.