What causes avascular necrosis: Avascular Necrosis – StatPearls – NCBI Bookshelf
Avascular Necrosis | Cedars-Sinai
What is avascular
Avascular necrosis is a disease that results from the short-term (temporary) or
lifelong (permanent) loss of blood supply to the bone. When blood supply is cut off,
bone tissue dies and the bone collapses. If avascular necrosis happens near a joint,
joint surface may collapse.
This condition may happen in any bone. It most commonly happens in the ends of a long
bone. It may affect one bone, several bones at one time, or different bones at different
What causes avascular necrosis?
Avascular necrosis may be the result of:
- Harm to
- Long-term use of medicines, such as corticosteroids
long-term use of alcohol
long-term (chronic) health conditions
Who is at risk for avascular
are more at risk if any of these apply to you:
- Bone surgery
disorders, such as sickle cell anemia
- Radiation treatments
disease or “the bends” (decompression sickness)
- Autoimmune disease
What are the symptoms of avascular necrosis?
following are the most common symptoms of avascular necrosis. But symptoms occur a
differently in each person. Symptoms may include:
early joint pain
pain gets worse as bone and joint start to collapse
range of motion because of pain
symptoms of avascular necrosis may look like other health conditions or bone problems.
Always talk with your healthcare provider for a diagnosis.
How is avascular necrosis diagnosed?
Along with a complete medical history and physical exam, you may have one or more
of the following tests:
- X-ray. This test uses energy beams to make images of internal tissues, bones,
and organs onto film.
This is an imaging test that uses X-rays and a computer to make
detailed images of the body. A CT scan shows details of the bones, muscles, fat, and
organs. CT scans are more detailed than general X-rays.
- MRI. This test uses large magnets, radio waves, and a computer to make detailed
images of organs and structures in the body.
This imaging test uses a very small amount of radioactive
material. It is injected into the blood to be seen by a scanner. This test shows
blood flow to the bone and cell activity in the bone.
The samples are looked at under a microscope. It’s done to find cancer or other
abnormal cells or to remove tissue from the affected bone.
assessment of bone.
These tests often are done during surgery to measure the
pressure inside the bone.
How is avascular necrosis treated?
Treatment will depend on your symptoms, age, and general health. It
will also depend on how severe the condition is.
goal of treatment is to improve your ability to use the joint and stop more damage
the bone or joint. Treatments are needed to keep joints from breaking down. They may
These are used to reduce weight on the bone or joint.
For this surgery, the inner layer of bone is removed to reduce
pressure, increase blood flow, and slow or stop bone and joint destruction.
- Bone graft.
into the affected area.
This surgery removes and replaces an arthritic or damaged joint
with an artificial joint. This may be considered only after other treatments have
failed to ease pain or disability.
treatments may include certain medicines and combination therapies to promote bone
Key points about avascular necrosis
- Avascular necrosis is a disease that results from the temporary or permanent loss
of blood supply to the bone. It happens most commonly in the ends of a long bone.
- Avascular necrosis may be the result of injury, use of medicines, or alcohol. Or it
may occur after bone injury or bone surgery.
- Symptoms may include joint pain and limited range of motion.
- Medicines, assistive devices, or surgery may be used to improve functionality or to
stop more damage to the affected bone or joint.
Tips to help you get the most from a visit to your healthcare provider:
- Know the reason for your visit and what you want to happen.
- Before your visit, write down questions you want answered.
- Bring someone with you to help you ask questions and remember what your provider tells
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments,
or tests. Also write down any new instructions your provider gives you.
- Know why a new medicine or treatment is prescribed, and how it will help you. Also
know what the side effects are.
- Ask if your condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if you do not take the medicine or have the test or procedure.
- If you have a follow-up appointment, write down the date, time, and purpose for that
- Know how
you can contact your provider if you have questions.
Medical Reviewer: Thomas N Joseph MD
Medical Reviewer: Raymond Turley Jr PA-C
Medical Reviewer: L Renee Watson MSN RN
© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional’s instructions.
Osteonecrosis of the Hip – OrthoInfo
Osteonecrosis of the hip is a painful condition that occurs when the blood supply to the head of the femur (thighbone) is disrupted. Because bone cells need a steady supply of blood to stay healthy, osteonecrosis can ultimately lead to destruction of the hip joint and severe arthritis.
Osteonecrosis is also called avascular necrosis (AVN) or aseptic necrosis. Although it can occur in any bone, osteonecrosis most commonly affects the hip. More than 20,000 people each year enter hospitals for treatment of osteonecrosis of the hip. In many cases, both hips are affected by the disease.
The hip is a ball-and-socket joint. The socket is formed by the acetabulum, which is part of the large pelvis bone. The ball is the femoral head, which is the upper end of the femur (thighbone).
The surface of the ball and socket is covered with articular cartilage, a smooth, slippery substance that protects the bones and enables them to glide easily across each other.
Osteonecrosis of the hip occurs in the femoral head, which is the ball of ball-and-socket hip joint.
Osteonecrosis of the hip develops when the blood supply to the femoral head is disrupted. Without adequate nourishment, the bone in the head of the femur dies and gradually collapses. As a result, the articular cartilage covering the hip bones also collapses, leading to disabling arthritis.
Osteonecrosis can affect anyone, but is more common in people between the ages of 40 and 65. Men develop osteonecrosis of the hip more often than women.
In osteonecrosis, the bone in the head of the femur slowly dies.
It is not always known what causes the lack of blood supply, but doctors have identified a number of risk factors that can make someone more likely to develop osteonecrosis:
- Injury. Hip dislocations, hip fractures, and other injuries to the hip can damage the blood vessels and impair circulation to the femoral head.
- 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.
- Corticosteroid medicines. Many diseases, including asthma, rheumatoid arthritis, and systemic lupus erythematosus, are treated with steroid medications. Although it is not known exactly why these medications can lead to osteonecrosis, research shows that there is a connection between the disease and long-term corticosteroid use.
- Medical conditions. Osteonecrosis is associated with other diseases, including Caisson disease (diver’s disease, or “the bends”), sickle cell disease, myeloproliferative disorders, Gaucher’s disease, systemic lupus erythematosus, Crohn’s disease, arterial embolism, thrombosis, and vasculitis.
Osteonecrosis develops in stages. Hip pain is typically the first symptom. This may lead to a dull ache or throbbing pain in the groin or buttock area. As the disease progresses, it becomes more difficult to stand and put weight on the affected hip, and moving the hip joint is painful.
It may take from several months to over a year for the disease to progress. It is important to diagnose osteonecrosis early, because some studies show that early treatment is associated with better outcomes.
The four stages of osteonecrosis. The disease can progress from a normal, healthy hip (Stage I) to the collapse of the femoral head and severe osteoarthritis (Stage IV).
Reproduced and adapted from Beaule PE, Amstutz, HC: Management of ficat stage III and IV osteonecrosis of the hip. J Amer Acad Orthop Surg 2004; 12: 96-105.
After discussing your symptoms and medical history, your doctor will examine your hip to discover which specific motions cause your pain.
Patients with osteonecrosis often have severe pain in the hip joint but relatively good range of motion. This is because only the femoral head is involved in the earlier stages of the disease. Later, as the surface of the femoral head collapses, the entire joint becomes arthritic. Loss of motion and stiffness can then develop.
During the exam, the doctor will move your hip in different ways to learn more about your pain.
Reproduced from JF Sarwark, ed: Essentials of Musculoskeletal Care, ed 4. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2010.
Imaging studies will help your doctor confirm the diagnosis.
X-rays. X-rays provide images of dense structures, such as bone. X-rays are used to determine whether the bone in the femoral head has collapsed and to what degree.
(Left) An X-ray of a healthy hip joint. (Right) In this X-ray, the osteonecrosis has progressed to collapse of the femoral head.
Osteonecrosis is typically seen as a wedge-shaped area with a dense whitish sclerotic (hardened) border in the superior lateral portion of the femoral head. On the lateral view, a line called a “crescent sign” can often be seen just below the surface of the femoral head.
(Left) This X-ray shows osteonecrosis of the hip. (Right) When viewed close up, the X-ray reveals the “crescent sign” that is typically seen before collapse of the femoral head.
Magnetic resonance imaging (MRI) scans. Early changes in the bone that may not show up on an x-ray can be detected with an MRI scan. These scans are used to evaluate how much of the bone is affected by the disease. An MRI may also show early osteonecrosis that has yet to cause symptoms (for example — osteonecrosis that may be developing in the opposite hip joint).
This MRI scan shows osteonecrosis in a patient’s right hip (white arrow). The dark line (red arrows) denotes the border between dead bone and living bone. The patient’s left hip is normal.
Although nonsurgical treatment options — such as anti-inflammatory medications, activity changes, and using crutches — can help relieve pain and slow the progression of the disease, the most successful treatment options are surgical. Patients with osteonecrosis that is caught in the very early stages (before the femoral head collapses) are potential candidates for hip-preserving procedures.
There are several different surgical procedures used to treat osteonecrosis of the hip.
Core Decompression and Grafting
This procedure involves drilling one large hole or several smaller holes into the femoral head to relieve pressure in the bone and create channels for new blood vessels to nourish the affected areas of the hip.
When osteonecrosis of the hip is diagnosed early, core decompression is sometimes successful in preventing collapse of the femoral head and the development of arthritis.
(Left) Illustration of core decompression. (Right) In this X-ray, the drill lines show the pathway of the small drill holes used in the procedure.
Core decompression is often combined with bone and cartilage grafting to help regenerate healthy bone and support cartilage at the hip joint. A bone graft is healthy bone tissue that is transplanted to an area of the body where it is needed. The tissue may be taken from a donor (allograft) or from another bone in your body (autograft).
There are also several synthetic bone grafts available today. Sometimes, your own bone marrow cells may be mixed together with the graft substitute to help in the bone regeneration process. It is importat to speak with your surgeon about the available options that may be used for your procedure.
Vascularized Fibula Graft
Another surgical option is a vascularized fibula graft. In this procedure, a segment of bone is taken from the small bone in your leg (fibula) along with its blood supply (an artery and vein). This graft is transplanted into a hole created in the femoral neck and head, and the artery and vein are reattached to help heal the area of osteonecrosis.
Two different X-ray views showing osteonecrosis of the hip.
Two X-ray views of the hip after treatment with a vascularized fibular graft.
Total Hip Replacement
In total hip replacement, both the head of the femur and the socket are replaced with an artificial device.
If osteonecrosis has advanced to the point where the femoral head has already collapsed, the most successful treatment is total hip replacement. In this procedure, your doctor removes the damaged bone and cartilage, then positions new metal or plastic joint surfaces to restore the function of your hip.
Core decompression prevents osteonecrosis from progressing to severe arthritis and the need for hip replacement in some cases. This depends upon the stage and size of the osteonecrosis at the time of the procedure.
Core decompression achieves the best results when osteonecrosis is diagnosed in its early stages, before the bone collapses. In some of these cases, the bone heals and regains its blood supply after core decompression. It takes a few months for the bone to heal and, during this time, you will need to use a walker or crutches to avoid putting stress on the damaged bone.
Patients with successful core decompression procedures typically return to walking unassisted in about 3 months and may have complete pain relief.
Vascularized fibular grafting is an invasive procedure that requires several months of healing. Typically, you are non-weightbearing for the first several weeks; you will then gradually start weightbearing with an ambulatory assistive device (walker or cane). If a vascularized fibular graft is performed prior to femoral head collapse, the clinical outcomes are usually favorable.
When osteonecrosis is diagnosed after collapse of the bone, core decompression is not usually successful in preventing further collapse. In this situation, the patient is best treated with a total hip replacement. Total hip replacement is successful in relieving pain and restoring function in the majority of patients with osteonecrosis.
Avascular Necrosis (AVN)/Osteonecrosis – together by St. Jude
Other names: OH, aseptic necrosis, ischemic bone necrosis
What is avascular necrosis (AVN)?
Avascular necrosis (osteonecrosis) is a condition in which part of the bone dies due to poor blood supply. Avascular necrosis may be a side effect of certain cancers or treatments.
Children at high risk are those receiving high doses of corticosteroids (dexamethasone and prednisone).
Avascular necrosis may be mild and improve after treatment is completed, or it may be severe, accompanied by severe pain and long-term disability.
Avascular necrosis in children with cancer
Avascular necrosis (AVN) is a common side effect of treatment for leukemia and lymphoma. Nearly half of children treated for acute lymphoblastic leukemia (ALL) suffer from some degree of avascular necrosis. In addition, the high-risk group includes children who have undergone bone marrow transplantation.
In children with cancer, avascular necrosis often occurs at the ends of long bones, at a site called the epiphysis.
This disease can affect any bone. However, in children with cancer, avascular necrosis often occurs at the ends of long bones, at a site called the epiphysis.
Avascular necrosis can be accompanied by pain and affect joint function, especially knee, hip, shoulder and ankle. Damage to the bone and joint can lead to long-term problems such as joint destruction and arthritis.
In cancer treatment, avascular necrosis is more common in older children and adolescents than in young children or adults. In children younger than 10 years, this condition is less common.
Avascular necrosis can be difficult to diagnose in its early stages. The patient may not experience pain or other symptoms until severe bone damage develops. The condition of high-risk children should be monitored throughout the course of treatment.
Treatment of avascular necrosis depends on the severity of the pain and the degree of bone destruction. Pain relief and physical therapy can help manage symptoms. Some patients may require surgery to improve blood flow and relieve pressure within the bone. In case of severe damage or destruction of the joint, the patient may eventually need arthroplasty.
Symptoms of avascular necrosis
Some patients may not show symptoms at all, especially in the early stages. As the condition worsens, pain in the joint or bone may appear. Family members may notice that the child has begun to limp, tries not to use the affected joint, stiffness or limitation of range of motion may become noticeable. Occasionally, avascular necrosis can lead to bone destruction, with the pain escalating dramatically.
Avascular necrosis can develop in one place or in several bones at once (multifocal course). Chemotherapy affects the entire body, so when treating childhood cancer, avascular necrosis usually occurs in several joints, most commonly in the knee and/or hip. Other joints, such as the shoulder and ankle, may also be affected.
In general, the presence of pain and disability depends on the following factors:
- Which parts of the bone are affected
- How severe is the avascular necrosis
- How quickly progresses
- To what extent the bone is able to regenerate
However, pain cannot be considered a reliable indicator of the severity of avascular necrosis. Avascular necrosis in a small area can be very painful. At the same time, other patients may not have pain at all, despite the very large area affected by avascular necrosis.
Symptoms of avascular necrosis
- Pain (may be temporary or permanent)
- Joint stiffness or “stuck”
- Lameness or change in gait
- Tendency not to use the affected joint or avoidance of certain activities
- Problems getting up or down stairs
Factors that increase the risk of developing avascular necrosis
- High doses of dexamethasone or prednisone as part of cancer treatment
- Age over 10 years
- Sickle cell disease
- High-dose bone irradiation
- Treatment with asparaginase and dexamethasone
- Congenital genetic changes
Causes of avascular necrosis
Avascular necrosis is a complex process. The main reason for the development of avascular necrosis is a decrease in blood flow to the bone. If the blood vessels are too thin, damaged, or clogged, nutrients and oxygen cannot reach the bone, causing bone cells to begin to die.
Cancer treatments, including chemotherapy and radiation, can cause bone cell death and/or affect bone repair. As a result, the bone can break down faster than it has time to recover from damage. In addition, the treatment may affect the blood supply to the bones, leading to avascular necrosis.
Many children receive corticosteroid drugs (eg, dexamethasone, prednisone) for chemotherapy. These drugs are also used to combat side effects such as nausea and swelling. However, corticosteroids can increase the level of fatty substances (lipids) in the blood. Accumulation of fats in blood vessels can lead to blockage. In addition, these drugs can cause changes in the cells that line the walls of blood vessels, thereby thinning and weakening blood vessels.
Chronic high-dose dexamethasone is associated with a higher risk of developing avascular necrosis than prednisone or intermittent dexamethasone. Some drugs, such as asparaginase, can also interfere with the action of dexamethasone and increase the risk of developing avascular necrosis because these drugs interact with each other. Other drugs (eg, methotrexate) can also cause bone damage and increase the risk of avascular necrosis, especially when used with corticosteroids.
Diagnosis of avascular necrosis
Different medical centers have different approaches to identifying patients at risk and monitoring their condition. Imaging methods are used to identify areas of avascular necrosis (sometimes called foci). Magnetic resonance imaging (MRI) is the most sensitive diagnostic imaging modality for diagnosing avascular necrosis. X-rays are less sensitive, but may be useful for monitoring progression and for monitoring the patient’s condition in the postoperative period. Less commonly, other methods such as bone scintigraphy and computed tomography (CT) are used.
Some clinics screen children at high risk to detect avascular necrosis even if they are asymptomatic. As a rule, such screening is part of a clinical or scientific research program and is mainly carried out for the knee and hip joints. When screening high-risk patients who are asymptomatic, the most common finding of avascular necrosis is on diagnostic imaging of the knee. As a rule, necrosis is observed on both sides of the knee joint (femoral and tibial), the knee may be the only affected joint. However, if avascular necrosis is found in the hip joint, the knees are also most commonly affected.
Avascular necrosis associated with high doses of corticosteroids usually becomes visible on MRI within the first year of therapy. If a patient does not show signs of avascular necrosis on MRI after 12 months of therapy, then even continued use of corticosteroids will most likely not cause the development of this condition.
Physicians are constantly looking for more accurate diagnostic methods through the use of more sensitive imaging techniques. In addition, research is underway in the field of predicting the development of avascular necrosis.
Progression of avascular necrosis
The course of avascular necrosis is difficult to predict. Lesions may grow, remain stable, or disappear. Progression can be fast or slow.
The severity (or stage) of avascular necrosis is important to know for treatment planning. Doctors consider two main factors:
- Size of lesions
- Is the bone on which the articular surface rests damaged
If the damaged bone cannot support the joint surface, the bone tissue under the cartilage will begin to break down. The normally smooth layer of cartilage that lines the joints begins to flake off. This leads to problems in the joint, including arthritis, pain and decreased mobility of the joint.
Joint destruction is more likely if the lesion is:
- close to the surface of the joint
- large, occupies 30% or more of the entire surface
- located in a weight-bearing joint (thigh, knee)
Since the knee and hip joints work under weight load, in severe cases of avascular necrosis, their destruction is quite common. If the focus of avascular necrosis in the hip joint occupies more than 30% of the joint surface, joint destruction usually occurs within 2 years.
Treatment of avascular necrosis
Treatment of avascular necrosis is always individual. Doctors take into account the following factors:
- Patient age
- Patient health and cancer stage
- Cancer treatment used and chemotherapy schedule
- Stage of avascular necrosis
- What bones and joints are affected
- Severity of pain
The main treatment is to relieve pain, keep the joint functioning and prevent further damage.
Treatment strategies may include the following:
Your doctor may prescribe pain medications, including NSAIDs (meloxicam, celecoxib) or acetaminophen. However, some painkillers put the patient at risk for bleeding, kidney or liver problems, or worsening the side effects of chemotherapy. Family members should check with their doctor before giving a child any medications, even over-the-counter medications, as they may interact with other medications or increase side effects.
Research is underway to prevent or treat avascular necrosis with drugs that affect blood flow, blood clotting, inflammation, fat metabolism, and/or bone cells. However, it has not yet been possible to achieve sustainable positive results.
Physiotherapy is an important part of the treatment of avascular necrosis. The physiotherapist will recommend how to reduce the weight load or eliminate painful activities. They may also prescribe special treatments, including:
- Exercises to help with the patient’s limitations (muscle weakness, joint stiffness, or trouble walking).
- Aids (walkers, crutches or canes) to aid mobility and reduce weight bearing on the affected joint. The physiotherapist will select the appropriate option and teach the patient how to walk with their help.
- Orthoses and support bandages (foot, knee or arm) support the affected joint and help reduce pain during daily tasks
- Instructions for home care, including gymnastics, recommendations for exercise and treatment with heat and/or cold
Avascular necrosis and weight-bearing effects
Reduced weight-bearing is recommended to avoid joint damage, severe pain and healing after surgery. However, many doctors and physiotherapists recommend that the patient perform light activities, as far as pain allows. Physical activity is important for increasing blood circulation, improving bone healing, and strengthening muscles, which reduces stress on the joints.
Patients with avascular necrosis should avoid high impact activities such as running, jumping and contact sports. This is especially important in patients with severe avascular necrosis to avoid joint destruction due to trauma.
Complementary or integrative therapies
The patient may benefit from psychosomatic therapies (eg, massage, acupuncture, biofeedback, and relaxation techniques). Special techniques help to cope with pain, reduce stress, reduce muscle tension and improve blood flow. Before using any new treatments, the patient’s family should consult with their physician to ensure they are safe and appropriate for the patient.
Adjustment of chemotherapy
In the case of severe avascular necrosis, the treatment team may recommend changing the chemotherapy plan to reduce the body’s exposure to corticosteroids. Such decisions should be made taking into account the risks to the health of patients in general.
Some patients require surgery to treat avascular necrosis. The operation will speed up the healing of the bone and prevent its further damage. Joint replacement may also be required. The following types of procedures are possible:
- Bone decompression – This procedure is performed to reduce pressure within the bone, increase blood flow and thereby improve healing speed. With this decompression, the surgeon drills small holes in the bone, cracking open the damaged tissue. After the dead tissue is removed, the voids can be filled with a bone graft. This is a minimally invasive surgery requiring only a small incision. It usually takes several weeks of rest or weight-bearing to heal. Typically, patients recover quickly and report less pain and improved joint function.
- Bone graft is a surgical procedure performed for avascular necrosis to replace and restore bone tissue with a bone graft. In this case, the transplanted tissue can be taken from the patient himself (from another bone, autograft) or from a donor (allograft). In addition, artificial materials can be used. If the cartilage is damaged, a combined bone and cartilage graft may be used. In some cases, blood vessels are also transplanted along with the bone tissue. This material is called a vascularized bone graft. It can help improve the blood supply to the joint. In avascular necrosis, bone grafting is most often used in conjunction with bone decompression.
- Arthroscopy is a type of minimally invasive procedure in which a miniature camera and fine surgical instruments are inserted through small incisions. In patients with avascular necrosis, arthroscopy may be used to repair torn cartilage, smooth the surface of a bone, or remove debris from inside a joint. This can relieve symptoms such as pain, stiffness, and a “stuck” joint.
- Osteotomy – This surgical operation is used to reduce the weight load on the affected area by reshaping or repositioning the bone. During this procedure, a wedge-shaped incision is made in the bone, after which the bone can be rotated, thereby changing the load on it. In the new position, the bone is held by plates, staples or screws until it heals. Osteotomy can help prevent joint destruction, delaying or eliminating the need for a joint replacement.
- Arthroplasty (Arthroplasty) – Joint replacement surgery may be required for severe bone disease. During this operation, the affected bone is removed and replaced with an artificial joint. Endoprosthetics may be needed for young patients after joint destruction. However, arthroplasty is also a common operation for adult cancer survivors who suffer from arthritis or who complain of worsening joint function years after treatment ends. Patients who have undergone joint replacement at an early age are likely to have to undergo repeated surgery in the future. Early diagnosis and treatment of avascular necrosis is important to prevent or delay arthroplasty.
Managing Avascular Necrosis: Tips for Patients and Families
Know your risks. Talk to your doctor about the patient’s cancer treatment (including doses received) and other risk factors.
Monitor your symptoms and get recommended tests. Seek medical attention if you develop pain or problems with your joints, especially if symptoms have not been observed before or if they worsen. Once your treatment is over, ensure that bone health is adequately addressed in your rehabilitation plan.
Stay physically active. Adjust your physical activity to reduce weight bearing and pay attention to pain as it will tell you what level of activity is acceptable. Avoid activities that involve pushing and falling, as well as contact sports – take care of bones and joints. If you’re not sure if a particular sport is okay to play, ask your doctor or physical therapist.
Wear shoes that provide support and use your prescribed orthoses and assistive devices. This is important as it helps to maintain proper joint alignment and function. Proper footwear also helps prevent falls and joint injuries.
Bone health and overall well-being depend on a healthy lifestyle:
Eat healthy foods, stay physically active, maintain a healthy weight, and don’t smoke.
Modified January 2019
Avascular necrosis. Description of the disease, methods of treatment
Avascular necrosis (osteonecrosis or bone infarction) is the death of bone tissue due to blockage of the blood supply. Hematopoietic cells are most sensitive to low oxygen levels and are the first to die after reduced blood flow (usually within 12 hours). This starts the process of bone marrow death and subsequent destruction of the entire bone.
The most common is avascular necrosis of the femoral head. Basically, the hip joint suffers from a combination of unreliable blood supply and high stress in this area while standing.
Symptoms and causes of avascular necrosis of the femoral head
At the initial stage of the disease, symptoms do not appear. Gradually, joint pain may develop, limiting the ability to move. With a complication, there is a risk of destruction of the bone or the nearby surface of the joint.
Major risk factors are bone fractures, hip dislocation, alcoholism and high dose steroid use. Sometimes, avascular necrosis can develop as a side effect of radiation therapy, chemotherapy, or organ transplantation. Osteonecrosis is also associated with diseases such as cancer, lupus, sickle cell anemia, HIV infections, Gaucher’s disease, and decompression sickness.
Examination for avascular necrosis of the femoral head
In the early stages of avascular necrosis of the bone, bone scintigraphy and MRI are the preferred diagnostic methods. X-rays at this stage of the disease often show no abnormalities. In the later stages, the picture looks less transparent than usual.
Treatment of avascular necrosis of the femoral head
Various methods are used to treat avascular necrosis of the femoral head. The most common approach is a total hip replacement.
Endoprosthetics for avascular necrosis of the femoral head is an effective method for the elderly. When installing a prosthesis in young patients, over time, a second operation may be required due to the expiration of its expiration date.
Other treatments include bisphosphonates. These are drugs that slow down the rate at which bone breaks down. Sometimes decompression (tunnelization) of the core of the affected hip bone is performed. The internal pressure of the bone is relieved by drilling a hole in it and implanting living bone tissue and an electrical device to stimulate new vascular growth.
A microvascular free fibula graft can also be placed for avascular necrosis. In this procedure, a portion of the fibula, along with its blood supply, is removed and transplanted into the head of the femur.