Avascular Necrosis (AVN) is a disease resulting in the death of bone cells. When involving the bones near a joint, it often leads to a collapse of the surface and subsequent arthritis due to an irregular joint surface. Avascular Necrosis is also termed as:
- Aseptic Necrosis
- Bone Infarction
- Ischemic Bone Necrosis
Although it can occur in any bone, avascular necrosis most commonly affects the ends (epiphysis) of long bones, such as the femur (thigh bone). Commonly, the effected bones are the upper femur, the lower femur, the upper humerus, and the bones of the ankle joint. The disease may affect just one bone, more than one bone at the same time, or more than one bone at different times.
Damage to the bones occurs from a lack of blood flow to bone cells – that often happens from an injury. It’s also often due to damage from drinking too much alcohol or taking corticosteroids to manage a chronic health problem. Overall, avascular necrosis is a serious condition, because the dead areas of bone do not function normally, are weakened, and can then collapse. Avascular necrosis ultimately leads to the destruction of the joint adjacent to the involved bone. The hip is the most common joint affected by avascular necrosis, followed by the knee, shoulder, ankle, elbow, and wrist.
Causes & Symptoms of Avascular Necrosis
Bone fractures or disease that prevent blood flow to the bone tissue causes avascular necrosis. In addition, there are two main types of causes that are associated with this condition, which are traumatic avascular necrosis and non-traumatic avascular necrosis, as described below:
- Traumatic avascular necrosis – This can occur after you break a bone or dislocate a joint.
- Non-traumatic avascular necrosis – This happens if you have an illness or medical condition that keeps blood from flowing to your bone tissue. Non-traumatic avascular necrosis often affects the same bones on both sides of the body. For instance, if you have avascular necrosis in your right shoulder, you’re more likely to have it in your left shoulder.
Avascular necrosis has many possible causes – loss of blood supply to the bone may lead to bone cell death and can be caused by an injury. At times, there may be no history of injury; however, other factors are associated with the disease such as taking steroids, alcohol usage, or blood coagulation disorders. Increased pressure within the bone is also associated with avascular necrosis.
The hip bone is the most commonly affected joint with avascular necrosis. This disease also commonly affects the bones in these specific areas:
In the early stages of avascular necrosis, no symptoms are presented. However, as blood cells die and the disease progresses, symptoms may occur, such as the following:
- Mild or severe pain in or around the affected joint.
- Groin pain that spreads down to the knee.
- Pain that occurs when putting weight on the hip or knee.
- Joint pain is severe enough to limit movement.
Pain can increase in intensity because of tiny breaks in the bone, called micro-fractures. These can cause the bone to collapse. Ultimately, the joint may break down and develop arthritis. The time between the first symptoms and the inability to move a joint varies. In general, it ranges from a few months to more than a year. Symptoms may also appear bilaterally (meaning on both sides of the body). If avascular necrosis develops in the jaw, symptoms include exposed bone in the jaw bone with pain or pus or both.
Who gets Avascular Necrosis?
Most doctors have identified a number of risk factors that can make someone more prone to develop avascular necrosis. The following factors linked to this disease include:
- Excessive alcohol use – Overconsumption of alcohol over time can cause fatty deposits to form in the blood vessels and can elevate cortisone levels, resulting in a decreased blood supply to the bone.
- Medical conditions – Avascular necrosis is associated with other diseases, including Caisson disease, sickle cell disease, Gaucher’s disease, systemic lupus erythematosus, Crohn’s disease, and vasculitis.
- Injury – Hip dislocations, hip fractures, and other injuries to the hip can damage the blood vessels and impair circulation to the femoral head.
- Corticosteroid medicines – Many diseases, including asthma, rheumatoid arthritis, and systemic lupus erythematosus, are treated with steroid medications. Although it isn’t known exactly why these medications can lead to avascular necrosis, research shows that there is a connection between the disease and long-term corticosteroid use.
- Smoking – Patients who smoke are highly prone to develop avascular necrosis.
- Age / Gender – Men develop avascular necrosis more than women, unless the cause is injury or lupus. It most often affects people ages 30 to 60. However, patients of any age can develop this disease.
It isn’t clear as to what causes the problem with blood flow to the bone. Sometimes avascular necrosis affects healthy people.
How Does Avascular Necrosis Affect You? How Serious is it?
Certain complications that are associated with avascular necrosis include the following below:
- Bisphosphonates – These medications that boost bone density could lead to avascular necrosis of the jaw – this could be more likely if you are taking them for multiple myeloma or metastastic breast cancer.
- Blood flow blockage – Blood clots, inflammation, and damage to your arteries can all block blood flow to your bones, later leading to avascular necrosis.
- Severe trauma – Breaking a hip can severely damage nearby blood vessels and cut the blood supply to your bones. Avascular necrosis may affect 20% or more of patients who break a hip.
Other complications associated with avascular necrosis include:
- Decompression sickness (which causes gas bubbles in your blood)
- Gaucher disease, in which a fatty substance collects in the organs
- Pancreatic (inflammation of the pancreas)
- Autoimmune diseases such as lupus
- Sickle cell disease
Recommended Treatment & Rehabilitation for Avascular Necrosis
During a diagnosis of avascular necrosis, after performing a complete physical examination, the doctor may use one or more imaging tests to help diagnose this disease:
An X-ray is a common tool that the doctor may first use to help diagnose the cause of joint pain. X-ray images may look normal in the early stages of avascular necrosis. This is likely to be normal because X-rays are not sensitive enough to detect the bone changes in the early stages of the disease. X-rays can show bone damage in the later stages, and once the diagnosis is made, they are often used to monitor the course of the condition.
MRI (Magnetic Resonance Imaging)
MRI is a common method for diagnosing avascular necrosis. Unlike X-rays, MRI detects chemical changes in the bone marrow and can show avascular necrosis in its earliest stages before it is seen on an X-ray. MRI may show diseased areas that are not yet causing any symptoms.
Your doctor may recommend a bone scan if your X-rays are normal and you don’t have risk factors. A single bone scan finds any bones affected by avascular necrosis.
CT (Computerized Tomography) scan
CT scans usually do not detect early avascular necrosis as early as MRI scans, but are the best way to show a crack in the bone. Occasionally it may be useful in determining the extent of bone or joint surface collapse.
A biopsy is a surgical procedure in which tissue from the affected bone is removed and studied. Although other imaging tests are used, biopsies are the least option to help diagnose avascular necrosis.
This can be beneficial for patients suffering from diseases of the hip, improving strength, stability, and recovery following a surgical procedure. Some common physiotherapy interventions in the treatment for avascular necrosis include:
- Manual therapy – hands-on care including soft tissue massage, stretching and joint mobilization by a physiotherapist can help improve alignment, mobility, and range of motion of the knee and hip. The use of mobilization techniques also helps to modulate pain.
- Therapeutic exercises – including stretching and strengthening exercises help regain range of motion and strengthen muscles of the knee and lower extremity to support, stabilize, and decrease the stresses placed on the bursa and tendons of the hip joint.
- Neuromuscular reeducation – This is to restore stability, retrain the lower extremity, and improve movement techniques and mechanics of the involved lower extremity to reduce stress on the hip joint in daily activities.
- Modalities – including the use of ultrasound, electrical stimulation, ice, cold laser, and other treatments to decrease pain.
- Exercises – Exercise or physical activity that doesn’t involve putting weight through joint pain is recommended, particularly for those that are in more advanced stages of avascular necrosis.
Conservative treatments may be used alone or in combination, but they do not always provide lasting improvement. Some patients may require surgery to permanently repair or replace the joint, such as the following:
This is a surgery that removes the inner layer of bone. This may reduce pressure within the bone and create an open area for new blood vessels to grow. Sometimes a piece of healthy bone with good blood vessels is put in this area to speed up the process. This procedure works best in the early stages of avascular necrosis and should help relieve pain and promote healing.
This is often done along with core decompression. A surgeon takes a small piece of healthy bone from another part of your body and grants (transplants) it to replace the dead bone. Alternatively, the surgeon may use a donor or synthetic bone graft. This surgery improves blood flow and helps support the joint.
Vascularized fibula graft
This is a more specific type of bone graft used for avascular necrosis in the hip. This surgery is more involved than some of the other options. A surgeon removes the small bone in your leg, called the fibula, as well as its artery and vein. The surgeon then grafts this bone into the hold created by core decompression. Finally, the surgeon re-attaches the blood vessels.
This involves taking out a piece of bone, typically a wedge, to reposition the bone so that the issue lacking blood supply bears less weight than an adjacent healthy area.
Arthroplasty is also referred to as a joint replacement. The affected bone is removed and replaced with an artificial joint. This treatment may be needed in the late stages of avascular necrosis or when a joint is destroyed.
Alternative & Homeopathic Treatment for Avascular Necrosis
In the early stages of avascular necrosis, symptoms might be eased with homeopathic treatments. Some of these are:
- Non-steroidal anti-inflammatory drugs (NSAIDs) – Medications, such as ibuprofen or naproxen might help relieve the pain associated with avascular necrosis.
- Rest – Reducing the weight and stress on your affected bone can slow the damage. You may need to restrict your physical activity or use crutches to keep weight off your joint for several months.
- Immobilization – Strapping or bracing may be beneficial to rest the joints and promote healing.
- Ice application – Applying an ice pack for 20 minutes a day may help reduce inflammation to the affected joint caused by the early stages of avascular necrosis.