All About Avascular Necrosis - Causes, Diagnosis, Treatment, Surgery, Cost
Avascular Necrosis (AVN) or osteonecrosis is a bone disease resulting from the temporary or permanent loss of blood supply to the bones. Without blood, the bone tissue dies, and ultimately the bone may collapse. If the process involves the bones near a joint, it often leads to collapse of the joint surface. AVN is also known as aseptic necrosis and ischemic necrosis.
While it can affect any bone, avascular necrosis most commonly affects the ends (epiphysis) of the femur, the bone extending from the knee joint to the hip joint. Other common sites include the upper arm bone (hymerus), knees, shoulders, ankles and the jaw. The disease may affect just one bone, more than one bone at the same time, or more than one bone at different times. Osteonecrosis is the underlying diagnosis in approximately 10 percent of hip replacements.
Osteonecrosis affects both men and women. It can occur in people of any age, from children to the elderly. However, it is most common in people aged 30 to 50 years.
Avascular necrosis causes
Common risk factors leading to avascular necrosis include excessive steroid use, alcoholism, and injuries such as fracture, dislocation, or some other joint injury.
Other risk factors include radiation therapy, chemotherapy, and organ transplantation (particularly kidney transplantation). Osteonecrosis is also associated with a number of medical conditions, including cancer, lupus, blood disorders such as sickle cell disease, HIV infection, Gaucher`s disease, Caisson disease, gout, vasculitis, osteoarthritis, and osteoporosis.
However, osteonecrosis also affects people with no health problems and for no known reason. Following are some potential causes of osteonecrosis and other health conditions associated with its development.
Avascular necrosis symptoms
Patients with avascular necrosis may have no symptoms in the early stages but most experience joint pain as the disease progresses. At first, the pain occurs only when putting weight on the affected joint. Later, it occurs even when resting. Pain usually develops gradually, and may be mild or severe. If osteonecrosis progresses and the bone and surrounding joint surface collapse, pain may develop or increase dramatically. In some cases, particularly those involving the hip, disabling osteoarthritis may develop. The period of time between the first symptoms and loss of joint function typically ranges from several months to more than a year.
Avascular necrosis diagnosis
After performing a complete physical examination and asking about the patient`s medical history, the doctor may use one or more bone imaging techniques to diagnose osteonecrosis. Some of the tests used to determine the amount of bone affected and how far the disease has progressed are:
- Magnetic Resonance Imaging (MRI)
- Computed/Computerized Tomography (CT scan)
- Bone Scan
- Functional Evaluation of Bone
Avascular necrosis treatments
Appropriate treatment for osteonecrosis is necessary to keep joints from breaking down. Without treatment, most people with the disease will experience severe pain and limitation in movement within 2 years. The goal in treating osteonecrosis is to improve the patient`s use of the affected joint, stop further damage to the bone, and ensure bone and joint survival.
Treatments offered may be non-surgical or surgical.
Non-surgical treatments include medications, reduced weightbearing, range-of-motion exercises and electrical stimulation. Although these treatments may relieve pain or help in the short term, for most people they don`t bring lasting improvement.
Most people with AVN will eventually need surgery. A number of different surgical procedures are used to treat osteonecrosis. These include:
- Core decompression: This surgical procedure removes the inner cylinder of bone, which reduces pressure within the bone, increases blood flow to the bone, and allows more blood vessels to form.
- Osteotomy: This treatment involves reshaping the bone to reduce stress on the affected area.
- Bone graft: This is the transplantation of healthy bone from another part of the body.
- Arthroplasty/total joint replacement or joint resurfacing: Total joint replacement is the treatment of choice in late-stage osteonecrosis and when the joint is destroyed. When the hip joint is involved, the treatment offered to older patients is called total hip replacement or THR. For younger patients, a new, more promising treatment is hip resurfacing or metal on metal resurfacing (MOM resurfacing) which is a bone preserving alternative to THR and results in faster recovery.
Cost of avascular necrosis surgery
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