Avascular Necrosis – Femur

Avascular Necrosis of the Femoral Head

John Miller Physiotherapist

Article by John Miller

Avascular Necrosis of the Femoral Head

What is Avascular Necrosis of the Femoral Head?

Avascular Necrosis of the Femoral Head, also known as Osteonecrosis, is a medical condition that affects the upper leg bone, specifically the femoral head. This condition occurs when the blood supply to the femoral head diminishes, leading to the death of the bone tissue. Over time, the bone may collapse, causing severe damage to the hip joint.

This condition typically affects individuals between the ages of 20-50 years old. However, the risk of developing Avascular Necrosis can be reduced by maintaining a healthy lifestyle. Avascular Necrosis often develops as a result of an underlying health issue or previous injury. Therefore, it is important to seek medical attention if you experience any symptoms, such as pain, stiffness, or limited mobility in your hip joint.

If left untreated, Avascular Necrosis of the Femoral Head can lead to long-term disability and chronic pain. Therefore, early diagnosis and treatment are essential. Treatment options may include medication, physical therapy, or, in severe cases, surgery. Consult with your healthcare provider to determine the best course of action for your individual needs.

What Causes Avascular Necrosis of the Femoral Head?

Avascular Necrosis of the Femoral Head can occur due to either traumatic or nontraumatic reasons. Traumatic avascular necrosis often arises from dislocated hips, where the femoral head becomes dislodged from its joint. In fact, up to 20% of people who suffer from hip dislocation develop Avascular Necrosis of the Femoral Head.

Nontraumatic avascular necrosis can be caused by various issues, including excessive alcohol consumption, chronic corticosteroid use, and blood clots/damage to the arteries that supply blood to the femur. The exact pathophysiology of how chronic corticosteroid and alcohol use are linked to Avascular Necrosis remains uncertain. However, overuse of these substances can cause the accumulation of fatty substances within blood vessels, leading to their narrowing and reduced blood flow to the femoral head. This reduction in blood supply can cause the bone tissue to die and undergo necrosis.

Avascular Necrosis of the Femoral Head can also be caused by certain diseases such as Gaucher’s Disease, diabetes, HIV/AIDS, sickle cell disease, pancreatitis, and autoimmune deficiencies/diseases. Additionally, medical treatments such as chemotherapy/radiation therapy, hypertension, vasculitis, and Caisson Disease can increase the risk of developing Avascular Necrosis. It is important to seek medical attention if you experience any symptoms to determine the cause and receive appropriate treatment.

What are the Symptoms of Avascular Necrosis?

Avascular Necrosis of the Femoral Head is a progressive condition that may not present symptoms in the early stages. However, as the condition progresses, patients may experience significant pain and limited hip range of motion. This pain can radiate down the length of the leg and become more pronounced when pressure is placed on the affected area, such as during walking.

In the early stages, Avascular Necrosis can be challenging to diagnose as its symptoms can mimic other conditions affecting the hip joint. Therefore, a detailed clinical history and thorough physical examination are essential in identifying the underlying cause of hip pain. Other symptoms may include stiffness, limping, and decreased mobility in the affected hip.

If you experience persistent hip pain, especially if it worsens over time and limits your mobility, seek medical attention promptly. Early diagnosis and treatment can prevent the condition from progressing and may lead to a better prognosis.

How is Avascular Necrosis Diagnosed?

Diagnosing Avascular Necrosis of the Femoral Head can be challenging, given its symptom overlap with other conditions affecting the hip joint. Once other potential causes have been excluded, diagnostic imaging of the hip is necessary to confirm the diagnosis.

The gold standard for diagnosis is magnetic resonance imaging (MRI), which is highly accurate in detecting the early stages of Avascular Necrosis. Researchers and radiographers have also proposed a classification system based on plain x-rays, known as the Ficat system, to help diagnose the condition.

Other scans such as bone or computed tomography (CT) scans may also be useful in specific stages of the injury. Once diagnosed, MRI can also be a valuable tool in monitoring the progression of the condition and the effectiveness of any treatment options.

If you are experiencing hip pain or limited mobility, consult with a healthcare professional. They will assess your condition and determine if further diagnostic testing, such as imaging, is necessary to identify the underlying cause of your symptoms. Early diagnosis is critical in preventing the condition from progressing and may lead to a better prognosis.

Avascular Necrosis Treatment

Avascular necrosis is a complex condition to treat and requires an individualised approach. Conservative treatment with physiotherapy has proven to be relatively ineffective for avascular necrosis. Although conventional treatment aims to decrease the weight-bearing load through the head of the femur (usually by implementing crutches), research has shown that the condition progresses in 1-2 years. Without definitive treatment, 70% to 80% of all avascular necrosis of the femoral head cases will progress and inevitably undergo surgery.

There have been nonoperative treatment options proposed. These treatment options are implemented before the femoral head collapses, and they are still in the early stages of research and development. Trials for various electromagnetic, acoustic stimulation or pharmaceutical modalities have varying success. One of the most well-known and successful early treatments is core decompression, where pressure inside the femoral head is decreased by drilling holes into the femoral head to create channels for new blood vessels to nourish the affected areas of the hip or by filling the drill canals with healthy bone from another body part. This technique has proven successful, especially in early-stage avascular necrosis, based on preoperative and postoperative MRI studies.

Surgical interventions include joint-preserving surgeries like osteotomy or bone reshaping, or total hip replacement, depending on the severity and stage of the condition. The primary goal is always to preserve the natural femoral head instead of replacing it.

It’s important to seek the advice of an orthopaedic specialist for individualised treatment options. Your doctor may suggest a combination of treatments, and the decision as to which treatment to select will depend on the stage of the avascular necrosis, in combination with the clinical evaluation of the patient.

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