Congenital tibial agenesis

　　Congenital tibial agenesis is a limb longitudinal defect, which is rare in clinical practice and the etiology is unknown. It may be due to embryonic developmental defects. According to Bardenheuer, in the early stage of embryo development, there is 1 main line and 4 feeding lines. The femur, fibula, 2 tarsal bones, and fifth toe are derived from the main line, and the tibia and other foot bones are derived from the lateral line. It is said that congenital tibial agenesis is caused by incomplete development of the first lateral line. Generally, most people agree with the theory of internal factors. Joachimstahl believes that it is caused by amniotic sac compression during fetal period.

　　Congenital tibial agenesis is often discovered in infancy, with the child presenting with shortening of the affected limb, abnormal appearance of the foot, difficulty in walking, knee flexion contracture, deformity of the lower leg, and poor muscle strength. Severe cases often have other deformities in the same limb, such as femoral agenesis, partial fibular agenesis, etc.

　　Congenital tibial agenesis is an unknown etiology, possibly caused by embryonic developmental defects. This disease is a congenital disease with no effective preventive measures. Good prenatal examination, early diagnosis and early treatment are the key to the prevention and treatment of the disease.

　　In the diagnosis of congenital tibial agenesis, in addition to relying on its clinical manifestations, auxiliary examinations are also needed. The X-ray manifestations of congenital tibial agenesis are characteristic, that is, the absence of tibia at different locations is relatively easy to make a correct diagnosis.

　　Congenital tibial agenesis is a rare clinical condition with an unknown etiology. Patients should have different dietary requirements according to different symptoms, and it is recommended to consult a doctor to develop specific dietary standards for specific diseases.

　　Congenital tibial agenesis is also very difficult to treat. The treatment method is usually selected according to the type of tibial agenesis, unilateral or bilateral lesions.

　　Type I Lesion

　　If there is unilateral type I tibial agenesis with poor development of the distal femur, knee disarticulation and prosthesis assembly should be performed at 2 to 3 years of age. For patients with bilateral type I tibial agenesis, Brown femoral and fibular osteotomy should be chosen to reconstruct knee function. Ankle arthroplasty is performed in the second stage; the distal end of the fibula is embedded in the pre-prepared concavity on the superior joint surface of the talus, and it is fixed longitudinally with Kirschner wires and externally fixed with plaster.

　　Type II Lesion

　　The treatment goal for type II lesions is to stabilize the knee joint, which can be achieved by tibial and fibular proximal fusion, fibular and talus fusion, and at the same time correct foot deformities.

　　Type III Lesion

　　For type III lesions, talo-fibular fusion should be performed to stabilize the hindfoot and improve foot function.