Avascular necrosis (AVN) is the death of bone tissue due to a lack of blood supply. Also called Osteonecrosis or Aseptic necrosis, or Ischemic bone necrosis.
It can lead to tiny breaks in the bone and the bone’s eventual collapse. A broken bone or dislocated joint can interrupt the blood flow to a section of bone.
Normally, the dead areas of bone don’t function, are gradually weakened, and ultimately collapse. This leads to the destruction of the joint adjacent to the involved bone.
It affects the knee, shoulder, ankle, elbow, wrist, and most commonly the hip. Some people develop AVN on both sides (bilaterally), such as in both hips or both knees. This affects people of age between 30 and 50 years commonly.
What Are the Factors Responsible for avascular necrosis?
Avascular necrosis is a localized bone death, caused by a variety of factors such as local injury (trauma), drug side effects, or disease. The main factors responsible are bone fractures, joint dislocations, alcoholism, and the use of high-dose steroids. Other risk factors include radiation therapy, chemotherapy, and organ transplantation.
Cancer, lupus, sickle cell disease, HIV infection, Gaucher’s disease, and Caisson disease (dysbaric osteonecrosis) are also responsible for this condition. The condition may also occur without any clear reason.
Bisphosphonates, are a class of drugs that are responsible for the osteonecrosis of the mandible. Prolonged and repeated exposure to high pressures (as experienced by commercial and military divers) leads to AVN.
As per Dr. Sudhir Babhulkar and Dr. Sushrut Babhulkar, a veteran in orthopedic surgery, who had done extensive research on this subject since 1970, they come in contact with 5 to 6 AVN patients daily, and at least 3-4 of them are due to steroids.
Symptoms of Avascular Necrosis
In its early stages, many people have no symptoms. As the condition gets worsens, it becomes painful when there is even slight weight on it. Then, pain may become constant.
Eventually, it may cause severe pain even when lying down. If the bone and surrounding joint collapse, you may have severe pain that makes you unable to use your joint. The time between the first symptoms and bone collapse can range from several months to more than a year.
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Is Covid Associated Avascular Necrosis Curable?
According to Dr. Babhulkar, if it is detected in the early stage or first stage, then it can be curable through medicines, in the second and third stages it requires surgical correction.
Whereas in the fourth stage, hip joint replacement surgery is the final remedy of AVN. This surgery can be conducted free of cost in GMCH under the scheme of Ayushman Bharat Yojna.
What are the Post-COVID Complications?
Now, Avascular Necrosis is also another worrisome problem during the first and second waves of Covid owing to the use of steroids.
Prolonged use of steroids causes bone tissue death in post-Covid patients. As a result of the long-term use of high-dose corticosteroids, many patients have been experiencing fungal infections like mucormycosis and avascular necrosis.
In the initial phase of Covid infected patients, the virus replicates and grows in the body. Nearly in the second week, the infected body produces overly vigorous immune responses by producing various inflammatory molecules (cytokines).
This uncontrolled immune response called cytokine storm causes severe inflammation and serious lung damage. In such a case, Steroid acts as the best anti-inflammatory drug that we have which lowers this inflammation.
However, excessive and prolonged use of steroids can suppress natural immunity when used for patients with low oxygen levels. Many patients using steroids hence experience problems like AVN.
Diagnosis of Avascular Necrosis
AVN can be classified into four stages; stages 1 and 2 are diagnosed by MRIs and X-rays, whereas it starts collapsing in stage 3. Hip replacement is only the option in the last stage.
Many disorders can cause joint pain. Imaging tests can help pinpoint the source of pain. Options include.
- X-rays. It can reveal bone changes that occur in the later stages of avascular necrosis. In the condition’s early stages, X-rays usually appear normal.
- MRI and CT scan. These tests produce detailed images that can show early changes in bone that might indicate avascular necrosis.
- Bone scan. In this method, when a small amount of radioactive material is injected into the patient’s vein it travels to the injured parts of the bones and shows up as bright spots on the imaging plate.
Reported Avascular Necrosis Cases in India
As per statements given by Dr. Mohn Faizal, Head of the Orthopedic Department of GMCH, orthopedic department of GMCH, in an interview of TOI in July 2021, they received two patients with AVN and both of them were on steroid therapy during their Covid treatment.
Patients who received more steroids will start facing AVN any time between 6 to 18 months of post-recovery.
Recently in July 2021, Dr. Sanjay R Agarwala and his group at Hinduja Hospital, Mumbai, published in the journal of BMJ Case Studies named “Avascular necrosis as part of Covid-19“.
In this report, he detailed the course of AVN diagnosis in the 3 patients reported in Mumbai. All these patients aged under 40 – were treated at Mumbai’s PD Hinduja Hospital in Mahim, and they developed AVN after two months after their Covid-19 treatment.
According to him, one patient aged 36 found AVN at 67 days, while, the other two aged 39 and 37 since 57 and 55 days respectively after the diagnosis of Covid-19.
All of these patients were administrated intravenous steroids as part of their Covid-19 treatment. Besides, the patients aged 36 and 37 didn’t have any history of hip pain.
Further 3 cases of AVN 32 to 40 years age group have been reported in Delhi’s BLK Super Specialty Hospital among the patients who have recovered from Covid-19. Two patients are under medication, while one had to undergo surgery.
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