What are the other Names for this Condition? (Also known as/Synonyms)

• Ankle Osteonecrosis
• Avascular Necrosis of Ankle
• Ischemic Necrosis of Ankle

What is Osteonecrosis of Ankle? (Definition/Background Information)

• Osteonecrosis (or avascular necrosis) is a serious bone disorder characterized by the temporary or permanent disruption of blood supply to the bone, which causes cells and tissues within the affected bone to die. In many, osteonecrosis affects the ends of the long bones in the body
• Osteonecrosis of Ankle affects bones in the ankle; frequently, the talus bone is affected. This bone in the ankle is responsible for transferring the weight of the body to the feet, via the tibia (or shinbone). The talus also forms a part of the ankle joint
• Osteonecrosis of Ankle can develop at any of the following joint locations:
  • Talocalcaneal or subtalar joint; a foot joint at the junction of the talus and calcaneus bone
  • Talonavicular joint; a complex joint consisting of two ankle joints - the transverse tarsal joint and the subtalar joint complex
  • Ankle joint, also known as the talocrural joint, occurs at the junction of the talus bone the tibia and fibula (calf bone)
• The cause of Osteonecrosis of Ankle may be categorized as either traumatic or non-traumatic. Trauma to the ankle causing bone fracture may occur from participation in sports or vehicular accidents; while, non-traumatic causes include the use of steroids, cancer therapy, alcoholism; or, it may even be idiopathic (of unknown origin)
• Individuals, who develop Osteonecrosis of Ankle, begin to experience pain within the affected bone/joint that usually progresses slowly. This may be accompanied by tenderness, swelling, and reduced range of ankle joint movement
• Treatment associated with Osteonecrosis of Ankle includes both nonsurgical and surgical methods. With early diagnosis and appropriate treatment, the prognosis is usually good. However, the prognosis also depends upon the severity of the condition and the underlying cause of Ankle Osteonecrosis

Who gets Osteonecrosis of Ankle? (Age and Sex Distribution)

• Osteonecrosis of Ankle may occur in individuals of all age, race, ethnic groups, and any gender
• A high percentage of individuals who develop the condition are young, middle-aged, or slightly older men in the age group 30-60 years

What are the Risk Factors for Osteonecrosis of Ankle? (Predisposing Factors)

Common risk factors associated with Osteonecrosis of Ankle include:

• Individuals, who sustain a dislocation or fracture, while participating in sports such as football or hockey
• Vehicular or industrial accidents involving the ankle joint
• Excessive consumption of alcohol
• Prolonged consumption of steroids, such as prednisone or glucocorticoids
• Myeloproliferative disorder: A bone marrow disorder characterized by the abnormal increase of red blood cells
• Cancer treatment using radiotherapy or chemotherapy
• Systemic lupus erythematosus (SLE): Autoimmune systemic inflammatory conditions that occur when an individual’s immune system create antibodies, which accidentally attack healthy tissues and organs within the body
• Decompression sickness: A disorder characterized by abnormal formation of nitrogen bubbles within the blood and tissues, usually seen in divers when they move up from the water (high-pressure medium) to the surface (low-pressure medium) too soon
• Sickle cell anemia: An inherited condition characterized by crescent-shaped red blood cells in the body, obstructing blood flow and causing reduced amounts of oxygen transportation
• Gaucher’s disease: A rare inherited disorder caused by excessive accumulation of fatty substances (lipid) in the cells and certain organs. This excess build-up of fatty substances can prevent the liver, spleen, lungs, bone marrow, and in rare cases the brain, from functioning properly
• Crohn’s disease: A disease causing inflammation of the digestive tract lining
• Antiphospholipid syndrome; an autoimmune disorder
• High cholesterol level causing hyperlipidemia
• Excess level of uric acid in blood causing hyperuricemia
• Arterial embolism: Blood flow obstruction to an organ or body part, caused due to an embolus (a blood clot or fat particle) within the artery
• Thrombosis: Blood clot that occurs within blood vessels
• Vasculitis: A condition that causes inflammation of blood vessels
• Long-term tobacco smoking
• Pregnancy, in some cases

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Osteonecrosis of Ankle? (Etiology)

In Osteonecrosis of Ankle, there is a loss of blood supply to the bone leading to its destruction and necrosis (tissue death). This blood supply loss may occur from a variety of factors that may be grouped as traumatic or non-traumatic. In some cases, the exact cause of osteonecrosis may remain unidentified (idiopathic).

Traumatic factors for Osteonecrosis of Ankle include:

• Injuries during sports participation causing ankle fracture
• Vehicular accidents
• Fall injuries

Atraumatic factors for Osteonecrosis of Ankle include:

• Excessive alcohol consumption and prolonged use of corticosteroids, which together account for about 4 in 5 cases of Ankle Osteonecrosis from non-traumatic factors
• Individuals with HIV infection or AIDS
• Perthes disease: Children who develop a rare childhood hip disorder caused by the temporary loss of blood flow to the ball portion of the hip joint
• Peripheral vascular disease: The contraction and hardening of blood vessels within the legs and feet
• Slipped capital femoral epiphysis: Adolescents develop this unusual condition, due to a weakness of the growth plate, causing the femur/thighbone head to slip backwards
• Sickle cell anemia: A genetic condition caused by odd-shaped red blood cells that tend to obstruct the flow of blood to different body parts
• Systemic lupus erythematosus (or lupus): An auto-immune systemic inflammatory condition that occurs when an individual’s immune system create antibodies that accidentally attack healthy tissues and organs within the body
• Decompression sickness: A disorder characterized by abnormal formation of nitrogen bubbles within the blood and tissues, usually seen in divers when they move up from the water to the surface too soon
• Radiation therapy, which uses high-energy beams to shrink tumors and destroy cancer cells
• Use of certain medications, such as during chemotherapy, steroids (usually high-dose), or immunosuppressive medications for organ transplant
• Excess fat in the body; obesity

What are the Signs and Symptoms of Osteonecrosis of Ankle?

The signs and symptoms of Osteonecrosis of Ankle may be mild or severe and can vary from one individual to another. It also depends on the specific ankle joint/bone to which the blood supply is cut-off. In some cases, there may be the involvement of more than one bone. Also, initially, there may not be any noticeable symptoms.

The signs and symptoms of Ankle Osteonecrosis may include:

• Noticeable pain and tenderness in the affected bone; the pain increases when pressure is applied to the bone
• The pain may be either dull or sharp and shooting pain; pain during sleep
• Swelling of tissue around the affected ankle bone or joint
• Decreased range of motion of the affected joint/bone; popping sound with movement of the affected ankle

How is Osteonecrosis of Ankle Diagnosed?

Diagnostic methods that a physician may use to help diagnose Osteonecrosis of Ankle include:

• Physical examination and evaluation of medical history
• Assessment of the signs and symptoms
• Functional evaluation of the affected bone
• Tests and procedures to diagnose any underlying condition, if any
• X-ray of the affected ankle: X-rays can help the physician rule-out other possible causes of ankle discomfort. During the early stages of osteonecrosis, it is difficult to locate the appearance of any abnormal bone changes. However, X-rays can usually identify the presence of osteonecrosis during the later stages
• Magnetic resonance imaging (MRI) of the ankle joint: An MRI is an imaging technique that creates images of soft tissues and bones, which helps detect any bone abnormalities, during the early stages of osteonecrosis
• Bone scan: A bone scan is a diagnostic method used to identify any bone abnormalities by injecting tiny amounts of radioactive material into the bloodstream
• Computerized tomography (CT) of the ankle joint: A CT scan takes a series of X-ray images from several different angles, which are then merged to create cross-sectional images of bones and soft tissues of the body. This allows a physician to examine the bone or joint and its surrounding structures

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Osteonecrosis of Ankle?

The complications associated with Osteonecrosis of Ankle may include:

• Further deterioration of the involved bone
• If left untreated, the bone may collapse
• Increased risk for fractures
• Immobility of the affected part/bone
• Chronic disability
• Complications that arise from any underlying condition, if present

How is Osteonecrosis of Ankle Treated?

The treatment of Ankle Osteonecrosis includes non-surgical and surgical methods and may depend on the severity of the condition (mild or severe). A healthcare provider may start with non-surgical treatment methods before adopting surgical procedures and techniques. These include:

• Applying ice to the region can help with pain and reduce swelling
• Avoiding further stress/weight on the involved bone, such as by using a pair of crutches; preventing further bone damage
• Non-steroidal anti-inflammatory oral medications, such as ibuprofen and naproxen, may be used to help decrease pain and swelling
• Medications for osteonecrosis may decrease the progression of this condition
• Corticosteroid injections help provide temporary relief of symptoms and in improving the range of motion. It is important to note that corticosteroid injections only give temporary relief. Prolonged episodes of such injections may injure the joints in the long-run
• Electrical stimulation therapy to aid in the growth of the affected bone
• After the symptoms has decreased, it is important to begin some light motion exercises.  Physical therapy may help restore strength, as well as provide flexibility to the muscles
• Use of specifically made  boot or footwear to avoid applying further pressure on the injured leg, till the condition heals

Surgical treatment measures include:

• Osteotomy: The affected bone is surgically removed/cut and reshaped or realigned
• Core decompression: Core decompression is used to treat early-stage osteonecrosis. In this surgical procedure the pressure within the bone is decreased by removing a part of the bone causing the abnormal pressure
• Arthrodesis of the ankle bone joint, when joint fusion techniques including bone grafting are used to surgically immobilize the affected bone
• Partial or total replacement of the involved joint: The involved joint is replaced through a surgical procedure using a prosthetic implant. A physician will recommend this surgical procedure, if the condition is limited to a certain portion of the joint
• Total arthroplasty: In total arthroplasty, the involved joint cartilage is completely removed. It is then replaced by a metal and plastic prosthetic implant. This surgical procedure is recommended, if the entire joint is acutely affected
• Cartilage grafting: Cartilage grafting is a surgical procedure to replace the damaged cartilage, which may be damaged due to osteonecrosis or any traumatic injury
• Bone grafting: It is a technique that involves removing a healthy bone from within the body and replacing the affected bone
• Stem cell therapy via stem cell injections may be an alternative to surgery, especially for young sports athletes

Additionally, suitable treatment of any underlying condition/disorder should be undertaken.

How can Osteonecrosis of Ankle be Prevented?

A few recommendations to help prevent Osteonecrosis of Ankle include:

• Avoid excessive intake of alcoholic beverages
• Monitor long-term consumption of steroidal medications
• Individuals, who participate in any high-risk sports, such as football or hockey, should wear appropriate safety equipment to help prevent a serious injury
• Undertaking adequate treatment for health conditions such as lupus
• Wear proper equipment while scuba-diving to avoid decompression sickness
• Maintain a low cholesterol diet
• Avail proper treatment that can help control or minimize blood vessel damage associated with vasculitis
• Proper treatment of Crohn’s disease will help prevent the development of osteonecrosis
• Undertake proper treatment of myeloproliferative disorder
• Treatments that improve the blood flow to organs or any body part
• Proper treatment of blood clots that occur within blood vessels

What is the Prognosis of Osteonecrosis of Ankle? (Outcomes/Resolutions)

• If treated early, a high percentage of individuals who develop Osteonecrosis of Ankle may show an improvement and experience favorable outcomes; the bone may rebuild itself
• In general, the amount of bone damaged by this condition significantly affects its prognosis. A delay in treatment or an absence of treatment can severely affect the prognosis and cause functional loss of the involved bone

Additional and Relevant Useful Information for Osteonecrosis of Ankle:

The following DoveMed website link is a useful resource for additional information:

https://www.dovemed.com/health-topics/orthopedc-disorders/