The hip joint is the joint that connects the pelvic bones to the thigh bones. The round part of the femur in contact with the pelvic bone is called the femoral head. A disease in which the blood flow to the femoral head is blocked due to various causes and necrosis of the bone tissue is called ‘avascular necrosis of the femoral head’. The hip joint can be damaged even with a light impact, as the tissues die rather than rot, and are prone to fracture or collapse. However, the femoral head has no symptoms even if the blood flow is blocked and necrosis progresses, and even if symptoms do appear, only stiff pain in the buttocks and groin area may appear, so the treatment time is often missed. To prevent this situation, let’s take a closer look at avascular necrosis of the femoral head with Shin Kwang-bae, an orthopedic surgeon at Ulsan Jeil Hospital.
◇ Few early symptoms
Avascular necrosis of the femoral head is asymptomatic in its early stages. After getting serious, you feel pain and go to the hospital. The pain starts in the groin and buttocks. The pain can range from mild discomfort to severe pain that makes you unable to move at all. It is sometimes mistaken for a herniated disc because of back pain. When the disease worsens, the pain is not felt when lying down or sitting, but the pain becomes more severe when changing positions or trying to walk. The pain is usually severe during the first walk, but after a few minutes of walking, the hip joint becomes soft or the pain is relieved. If the femoral head is depressed or the joint is swollen, it is impossible to walk due to severe pain.
In the initial situation, X-rays often do not show normal findings or necrotic areas. For this reason, it is difficult to diagnose with simple radiography alone. It cannot be detected at an early stage unless nuclear medicine tests or magnetic resonance imaging (MRI) are used. A bone scan (bone scan) test can diagnose the disease at an early stage, but it is less accurate than MRI on the size and location of the lesion. Generally speaking, if a middle-aged man in his 30s or 50s feels pain in the area next to the groin and it is difficult to sit cross-legged, this disease should be suspected.
◇Recently, it also occurs in young people
Risk factors for avascular necrosis of the femoral head include alcohol consumption, corticosteroid administration, hip joint trauma, diving disease, gout, serum lipid abnormalities, chronic renal disease, and chronic pancreatitis. Among them, alcohol and corticosteroids account for about 90% of the total causes.
This disease is more common in young people recently. The reason is that excessive drinking, various skin diseases, and organ transplantation are on the rise, so steroids are being taken a lot. Alcohol builds up fat in the blood vessels, and in severe cases, prevents blood from passing through the femoral head, eventually causing bone death. However, idiopathic necrosis of unknown etiology is still occurring.
Shin Kwang-bae, an orthopedic surgeon at Ulsan Jeil Hospital, said, “If avascular necrosis of the femoral head in one hip joint progresses, there is a high probability of necrosis in the other hip joint as well. “The causes of avascular necrosis of the femoral head are diverse, but the course of progression is similar. In other words, the bones that do not receive enough blood die, and as a result, the bones collapse and eventually damage the cartilage, leading to arthritis.”
◇Reduce exposure to risk factors
If avascular necrosis of the femoral head is diagnosed at an early stage, it is highly likely to recover, so early diagnosis is important. There are four main types of treatment methods.
In some cases, follow-up can be done without any special treatment first. If there is necrosis, but it is small and in a good location, or if there is pain but it is not severe and does not interfere with daily life, you can just watch it.
Another case can be treated with decompression surgery to reduce the pressure in the necrotic area. Decompression surgery is a treatment that attempts to delay or avoid artificial joint surgery in young patients.
A third is what is called a rotational osteotomy or salvage. Rotational osteotomy is a surgical method in which a bone is cut and then the necrotic area is moved to a non-weight-bearing area. It can be performed in young patients diagnosed at an early stage of necrosis or in patients who have already experienced fractures and depressions but have no or mild degenerative changes.
Finally, there is artificial arthroplasty. Arthroplasty is an operation to remove a damaged joint and insert an artificial joint. It is the most reliable and most often implemented. For elderly patients, it is more effective to perform artificial joint surgery than to maintain the original joint even if the head is not deformed or the disease is mild. However, since the lifespan of the artificial joint is limited, reoperation to replace the artificial joint with a new artificial joint is required when the lifespan of the artificial joint expires.
Shin said, “Currently, there is a lack of clarity on the cause of avascular necrosis of the femoral head. Because of this, there is no special prevention method, but exposure to risk factors such as excessive drinking and avoiding unnecessary use of corticosteroids (steroids) is recommended. It is better to reduce it,” he said.
By Jeon Sang-heon, staff reporter [email protected]