● Avascular necrosis of the femoral head in children is a self limited disease, which can heal without treatment, but may leave deformities and joint movement disorders of varying degrees

When it comes to necrosis of the femoral head, many people can't help but think of the elderly who are unable to move in wheelchairs. They never think that young children who are usually energetic and lively may also be threatened by this kind of pain. However, in fact, children who often like to run, jump and jump violently are likely to suffer trauma to their hips during a large number of explosive jumping exercises, and some even damage their blood vessels, leading to partial or even complete interruption of blood supply to the femoral head, and the femoral head epiphysis eventually becomes necrotic due to lack of blood.

　　 case

Boy often suffers from leg pain and bone necrosis is found

Six year old Jiezai began to suffer from leg pain half a year ago. After massage, he had a rest and was fine. At first, the family thought that the little boy was too naughty. He had played too much in climbing up and down and skipping. Later, the suspicious mother insisted on taking the child to the doctor, and went to the hospital for an examination. The result showed that Jay was suffering from avascular necrosis of the femoral head!

This scared the whole family. Grandma, who often suffers from waist aches and leg pains and is a bit "cured after a long illness", reminded his parents with an authoritative tone: "Femoral head necrosis is very serious. If it is not good, it will have to be replaced, and maybe paralyzed. But this disease is easy for adults to get. How can Jay get this disease even when he is so young?"

The anxious parents went to the doctor again, but the doctor told them: "The avascular necrosis of the femoral head in children is different from that in adults, which is not as serious as the old people think. But we really need to pay close attention to treatment, so as not to grow short legs and affect the normal development in the future."

　　 Active boys aged 4-9 are prone to disease

"The occurrence of avascular necrosis of the femoral head in children is generally hidden. Children usually start to complain about the pain in the knee joint. The pain will worsen when running and walking too much, but the pain symptoms can be relieved after rest." Professor Zeng Yirong explained that children with avascular necrosis of the femoral head often suffer from knee pain first, mainly because of the damage of the tissues around the hip joint, The blood vessels supplying the femoral head are also "implicated", resulting in insufficient blood supply in the local area, affecting the obturator nerve, thus causing pain in the knee.

At present, the true cause of avascular necrosis of the femoral head in children is still unclear in the medical community. It is generally believed that the epiphyseal avascular necrosis occurs because the tissues around the hip joint of children are damaged, leading to vascular damage, and the femoral head is not adequately nourished. About 80% of these children are at the age of 4 to 9 years old. Most of them are unilateral. Bilateral lesions generally account for about 12%, and the proportion of men and women is about 4:1.

Why do most children get sick when they are 4 to 9 years old? This is because before the age of 8, the blood supply of the femoral head is mainly provided by one vessel, which is clinically called the epiphyseal artery. Most children at this stage are energetic and active, especially boys, who like to run, jump and jump. If the amount of exercise is too large, especially in the intense and explosive jumping process, which causes hip trauma, blood vessels may be damaged, leading to partial or even complete interruption of blood supply to the femoral head, and the femoral head epiphysis will eventually become necrotic due to ischemia.

Causes of leg pain in children need to be carefully identified

"Fortunately, avascular necrosis of the femoral head in children and necrosis of the femoral head in adults are two completely different diseases." Zeng Yirong pointed out that the former is a curable self limited disease, and its natural course is generally 2-4 years. In other words, if not found, without treatment, the lesions can also heal, but may leave varying degrees of deformity and joint movement disorders.

"But it is found that the child's knee pain in the growth process should not be too tense, and it is not necessarily a problem of the femoral head." Zeng Yirong analyzed that, in addition to avascular necrosis of the femoral head, the child's leg pain also has the following possibilities:

Growth pain: The child's leg often hurts obviously at night, but it will be fine the next day. Usually, no special treatment is needed. In case of an attack, just reduce the activity and rest more, and massage or hot compress the local area to relieve the symptoms.

Transient synovitis: If inflammation is found in time, physical therapy and reasonable rest are required. Generally, it can heal itself within half to one month. However, a small number of children develop femoral head necrosis, so it is recommended to take regular reexamination.

Fracture: The child usually has a clear history of trauma, and the appearance of the injured part may be swollen or even bent or angulated.

　　 prevention and cure

Children should not run or jump violently

Zeng Yirong said that being active is the nature of children. It is not conducive to the growth of the body to let children stay quietly all day long. However, experts suggest that parents should be more careful when helping their children choose sports types, and play less sports that require intense and explosive running, jumping and jumping, such as trampoline, while swimming, cycling and playing basketball can also achieve the purpose of exercise.

Parents should also pay more attention in daily life. If the child is found to have continuous knee pain or even limping, but no abnormality can be found in the knee joint, it is necessary to consider whether there is femoral head necrosis. Zeng Yirong suggested that the hip joint should be checked by CT, MRI, etc.

As long as it is diagnosed and treated as soon as possible, the adverse factors affecting the growth of the femoral head epiphysis can be eliminated as soon as possible, the secondary malformation of the femoral head and the osteoarthritis of the hip joint can be prevented or alleviated, and the necrotic femoral head can successfully complete its self repair process.

For late stage children, if there is femoral head dislocation, surgery (pelvic osteotomy) is required, and the effect is still good. However, some children with advanced diseases may still have the problem of lower limb shortening after surgery, and they will limp when walking. Therefore, early detection and early treatment are particularly critical. (By Weng Shuxian, correspondents Fang Ning and Zhang Qiuxia)

Medical guidance/Professor Zeng Yirong, Deputy Director of Arthrology Department of the First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine

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