Osteonecrosis – Know It All!
All you need to know about Osteonecrosis.
Know your ailment well, so you can manage it better!!
Here we come with Osteonecrosis today!
Avascular necrosis caused by a lack of blood flow is the death of bone tissue. Also known as osteonecrosis, it can cause tiny cracks in the bone and subsequent collapse of the bone. The blood supply to a bone segment may be disrupted by a fractured bone or dislocated joint.
Although this can occur in any bone, osteonecrosis most commonly affects the ends (epiphysis) of long bones like the femur ( thigh bone). The upper femur (ball part of the hip socket) the lower femur (a part of the knee joint), the upper humerus (upper arm bone that includes the shoulder joint), and the ankle joint bones are usually involved. The disease can affect only one bone, more than one bone at a time, or more than one bone at a time. The disorder is most commonly diagnosed by orthopedic surgeons using either an X-ray magnetic resonance scan (MRI).
The amount of damage arising from osteonecrosis depends on what portion of the bone is damaged, how big an area is involved, how much the disease has advanced and how quickly the bone itself is repaired. The bone healing process takes place both after an injury and during normal development. Normally, bone fractures and rebuilds constantly-old bone is reabsorbed and replaced by new bone. The process keeps the skeleton solid and helps it retain mineral balance. Typically the healing process is incomplete with osteonecrosis, and the bone tissues break down faster than the body can rebuild them. The disease develops if left untreated, and the bone may develop a crack whereby the bone may be compressed (collapse) together (similar to a snowball being compressed). If this happens at the end of the bone, an abnormal joint surface, arthritic pain and loss of function of the affected areas may result.
What happens in Osteonecrosis:
The lack of blood flow to the bone is causing osteonecrosis. The bone tissue dies without blood which causes the bone to break down and collapse.
The body is creating new bone in people with healthy bones to replace old or broken bones. This process takes place during normal growth and for keeping the bones intact after an injury. If you have osteonecrosis, the bone breaks down faster than enough fresh bone can produce.
The prognosis for osteonecrosis sufferers varies from person to person. It depends on the part of the bone is damaged by osteonecrosis, how much of the bone is damaged and how well the bone itself is healed.
Most people with osteonecrosis need care to avoid more damage to the bone, protect the bones and joints and enhance the use of osteonecrosis joints.
Without medication, the condition worsens and the bone and joints break down, and within two years, most people with the disease will experience intense pain and reduced mobility.
Who gets the disease:
Osteonecrosis typically affects people between the ages of 30 and 50; in the United States, about 10,000 to 20,000 people experience osteonecrosis per year. Osteonecrosis affects men and women alike and affects people of every generation. It is most popular among people in their 30s and 40s. It may also affect younger or older people depending on the risk factors of an individual, and whether the underlying cause is trauma.
Patients do not show any symptoms at the early stages of osteonecrosis. However, when the disease progresses, most patients feel joint pain — first, then when the affected joint is put to weight, and then also while resting. Pain is generally incremental and can be mild or extreme. If osteonecrosis progresses, and the joint surface of the bone and surrounding area collapses, pain may develop dramatically or increase. By restricting the range of motion in the affected joint, discomfort can be extreme enough to cause joint stiffness. It can grow debilitating osteoarthritis in the affected joint. With each case , the time between the first signs and the loss of joint function is different, varying from several months to more than a year.
The causes of osteonecrosis are numerous. Loss of blood supply to the bone may lead to the death of the bone cell and may result from injury (bone fracture or dislocation of the joint; called traumatic osteonecrosis); At times, there may be no history of injury (non-traumatic osteonecrosis); however, other risk factors such as certain drugs (steroids, also known as corticosteroids), alcohol consumption, or blood coagulation disorders are associated with the condition. Osteonecrosis is also associated with elevated pressure within the bone. One hypothesis is that blood vessels are limited by the strain within the bone, making it impossible for the blood to pass through the bone. It can also link osteonecrosis with other disorders. For certain risk factors, the exact cause of osteonecrosis progresses isn’t completely known. Osteonecrosis also occurs in people with no (idiopathic) risk factors. Some people have a number of risk factors. Osteonecrosis is most likely due to the combination of factors, including possible genetic, metabolic, self-imposed (alcohol, smoking), and other diseases you may have and their treatment.
When a joint is broken, as in a fracture or dislocation, it may cause damage to the blood vessels. This can interfere with the bone’s blood supply and contribute to osteonecrosis associated with a fracture. Studies indicate that more than 20 percent of people who dislocate their hip joint may develop this form of osteonecrosis.
- Corticosteroid Medications:
Corticosteroids, such as prednisone, are widely used to treat infectious diseases such as systemic lupus erythematosus, rheumatoid arthritis, inflammatory intestinal disease, and vasculitis. Studies indicate that long-term, high-dose systemic (oral or intravenous) usage of corticosteroids is a significant risk factor for non-traumatic osteonecrosis with estimates of up to 35 percent of all non-traumatic osteonecrosis individuals. There is also little chance of osteonecrosis associated with the occasional use of corticosteroids, inhaled corticosteroids, or certain injections of steroids into joints. Patients should address questions with their doctor about the use of corticosteroids.
Doctors aren’t sure precisely why osteonecrosis often requires the use of corticosteroids. They may have adverse effects on various organs and tissues within the body. They could interfere, for example, with the ability of the body to create new bones and break down fatty substances. Then these substances will accumulate in and block the blood vessels, causing them to widen. That would then reduce blood’s ability to flow within a bone.
- Alcohol Use:
Another big risk factor for nontraumatic osteonecrosis is heavy use of alcohol. Studies also recorded that around 30 percent of all people with non-traumatic osteonecrosis account for alcohol. While alcohol can delay bone remodeling (the balance between new bone formation and bone removal), it is not known why or how alcohol may cause osteonecrosis.
- Other Risk Factors:
Such non-traumatic osteonecrosis risk factors or conditions include Gaucher disease, pancreatitis, autoimmune disease, cancer, HIV infection, decompression disease (Caisson disease), and blood disorders such as sickle cell disease. Some medical treatments can cause osteonecrosis including radiation treatments and chemotherapy. People who have been given a kidney transplant or another organ transplant may also be at increased risk.
How to diagnose:
The doctor may use one or more imaging techniques to diagnose osteonecrosis after conducting a full physical exam and asking about the patient’s medical history (for example, what health issues the patient has had and for how long). As for many other conditions, early diagnosis increases the likelihood of successful treatment.
The doctor’s likely to prescribe an x-ray first. X-rays can help determine certain types of joint pain, for example, a fracture or arthritis. If the x-ray is regular, further testing may be needed for the patient.
Study studies have shown that magnetic resonance imaging ( MRI) is at present the most effective approach for early-stage diagnosis of osteonecrosis. The tests listed below can be used to assess how much bone has been infected and how much the disease has advanced.
- X-rays. An x-ray is a popular instrument that can be used by the doctor to help determine the source of joint pain. It’s an easy way of creating photographs of bones. An early-osteonecrosis person’s x-ray is likely to be normal as x-rays are not sensitive enough to detect changes in the bone at the early stages of the disease. X-rays may display bone damage at the later stages and are also used to track the progression of the disease after the diagnosis is made.
- Magnetic resonance imaging (MRI). MRI is a popular diagnostic tool for osteonecrosis. In comparison to x-rays, bone scans, and CT scans (computed / computerized tomography), MRI measures chemical changes in the bone marrow and may reveal osteonecrosis in its early stages before it is seen on an X-ray. MRI gives the doctor a description of the affected region and the method of bone reconstruction. Furthermore, MRI may display diseased areas which are not yet causing symptoms. An MRI uses a magnetic field and radio waves to create sectional images of organs and tissues of the body.
- Bone Scan: A bone scan is an imaging type that is used in patients with regular x-rays and with no risk factors for osteonecrosis. A bone scan can detect all bones and joints that are impacted by osteonecrosis in the body. In this test, a harmless radioactive substance is injected into the body, and a special camera takes an image of the bone. The photo illustrates how the fluid implanted in bone moves through the blood vessels.
- Computed/Computerized Tomography (CT): A CT scan is an imaging technique that gives a three-dimensional image of the bone to the doctor. It also reveals bone “slices,” which render the image much better than x-rays and bone scans. Typically CT scans do not detect early osteonecrosis as early as MRI scans but are the best way to display bone crack. It may be useful sometimes to assess the degree of collapse of the bone or joint surface.
A biopsy is an operative process in which tissue is removed and examined from the affected bone. It is seldom used for diagnosis, as other imaging tests are typically sufficiently distinct to allow a high degree of trust in the diagnosis.
Effective osteonecrosis treatment is required to avoid deterioration of the joints. If untreated, the majority of patients will experience extreme pain and mobility restrictions within two years. There is no accepted ideal cure for osteonecrosis patients. In order to protect the joints, early diagnosis is necessary but most people are diagnosed late in the disease process.
There are many therapies that can help prevent further damage to the bone and joint, and relieve discomfort. The doctor considers the following aspects of a patient’s disease to assess the most suitable treatment: age of the patient; stage of the disease — early or late; position and amount of bone affected — a small or wide region. The underlying cause was found to have little effect on treatment outcomes.
The purpose of treating osteonecrosis is to improve the use of the injured joint by the patient, avoid more bone deterioration, and ensure bone and joint survival. When osteonecrosis is diagnosed early enough, it can avoid deterioration and replacement of the joints. The doctor may use one or more of the following therapies to attain these goals.
Osteonecrosis has no known therapeutic solution. Several non-operational therapies have been studied including hyperbaric oxygen therapy, shock wave therapy, electrical stimulation, pharmaceuticals (anticoagulants, bisphosphonates, vasodilators, lipid-lowering agents), physiotherapy and muscle-enhancing exercises, and their combinations. Some of these treatments have inconsistent outcomes, so systematic, randomized controlled trials with large numbers of patients are also needed to assess the efficacy of such treatments. Non-operational care may be part of a wait-and-see strategy based on the size of the dead bone region. Non-operative procedures can not be classified as restrictive, as many of them do not delay the progression of the condition or lead to a complete hip arthroplasty being prevented. At most, most are just pain relievers.
Reduced weight bearing does not change the disease course and is not a cure. It may be used simply to allow the patient to cope better with the pain before proper care is implemented.
Core decompression — This surgical technique eliminates or drills a tunnel into the affected bone area which reduces bone pressure. Core decompression works better with those that are in the early stages of osteonecrosis until the dead bone collapses. This operation can also alleviate discomfort and delay bone and joint damage development in certain patients.
Osteotomy — This surgical technique reshapes the bone to relieve stress on the region affected. There is a long recovery time, and after an osteotomy, the patient’s activities are very limited for 3 to 12 months. This treatment is most successful for advanced osteonecrosis patients and those with a small region of the affected bone.
Bone grafting-Bone grafts can be used as part of the osteonecrosis surgical procedure. Bone grafts can be used from the same patient’s or donor bone. Bone graft or synthetic bone graft may be inserted via the core decompression procedure into the hole developed. A specific technique , called vascularized bone grafting, involves transferring a fragment of bone from another location with a vascular connexion (often the fibula, one of the calf’s bones, or the iliac crest, a part of the pelvic bone). This enables treatment in both the diseased region and a new source in blood supply. This is a complicated operation, which is conducted by specially qualified surgeons. Another form of bone grafting involves scrapping all the dead bone and replacing it with healthy bone grafting, mostly from other parts of the skeleton of the patient.
A special form of bone graft requires the use of a patient’s own cells to produce fresh bone. These cells are also a type of stem cell derived from the bone marrow or other body tissues. The promise of stem cell therapy has become increasingly of interest. Even this is being investigated for osteonecrosis therapy. Mesenchymal stem cells, which are a type of ‘adult’ stem cell, can develop into several different types of cells within the body. Doctors take own mesenchymal stem cells (autologous transplant) from the patient and insert them in the damaged bone to promote bone repair and regeneration.
Arthroplasty / complete joint replacement-Total joint replacement is the late-stage osteonecrosis treatment of choice when the joint is damaged. In this surgery, artificial parts of the diseased joint are removed. For those who are not suitable candidates for other procedures, such as patients who may not perform well with frequent efforts to save the joint, this might be prescribed. Various types of replacements are available, and people can speak with their doctor about their needs.
Treatment is an ongoing procedure for most osteonecrosis sufferers. First, physicians should prescribe the least complicated and invasive treatment, such as protecting the joint by restricting high impact movements, and monitoring the effect on the health of the patient.
Other therapies can then be used to avoid further bone loss and relieve pain such as bone graft / system cell therapy core decompression. Ultimately, patients may need to replace the joint if the disease has advanced toward bone collapse. It is important that patients follow guidelines on limits of operation carefully and work closely with their doctor to ensure effective medications are used.
Gopala Krishna Varshith,
Content Developer & Editor,