Avascular necrosis (AVN) of the femoral head, also known as osteonecrosis, is a condition where blood supply to the hip joint is disrupted. Without adequate circulation, bone tissue in the femoral head begins to die, potentially leading to joint collapse and severe mobility issues.
AVN often develops gradually, and early detection is crucial to preventing long-term joint damage. Although it can affect individuals of any age, it is most commonly seen in people between 20 and 50 years old. Maintaining a healthy lifestyle and addressing underlying medical conditions can help lower the risk of developing AVN.
What is Avascular Necrosis (AVN)
AVN can develop due to two primary causes: traumatic injury and non-traumatic factors.
Traumatic Causes
Avascular necrosis frequently occurs following hip dislocation or fractures, which can disrupt the blood vessels supplying the femoral head. Studies suggest that up to 20% of individuals with hip dislocations eventually develop AVN.
Non-Traumatic Causes
Certain medical conditions and lifestyle factors can contribute to AVN without direct injury. These include:
Excessive Alcohol Consumption – Heavy alcohol use may lead to fat buildup in blood vessels, reducing circulation to the hip.
Long-Term Corticosteroid Use – Prolonged steroid use, often prescribed for inflammatory conditions, is associated with AVN development, though the exact mechanism remains unclear.
Blood Clotting Disorders – Conditions that impair blood circulation can restrict oxygen and nutrient delivery to the femoral head.
Medical Conditions – Diseases such as diabetes, sickle cell disease, lupus, and HIV/AIDS can increase the risk.
Cancer Treatments – Radiation and chemotherapy may weaken bone structure and affect blood supply.
Obesity: Increased weight can increase the likelihood of AVN due to the increased fat cells in the femoral head (hyperlipidemia).
What Causes Avascular Necrosis?
In the early stages, AVN may not produce noticeable symptoms. As the condition progresses, individuals typically experience:
Hip pain that worsens over time – Initially mild, pain can intensify and radiate to the groin, thigh, or knee.
Stiffness and reduced mobility – Activities like walking, bending, or sitting for extended periods may become challenging.
Limping – As the femoral head weakens, weight-bearing becomes painful, altering gait patterns.
Increased discomfort with activity – Pain may be more pronounced when putting weight on the affected leg.
If you are experiencing persistent hip pain, seek medical evaluation to determine the underlying cause.
Symptoms of Avascular Necrosis
Diagnosing Avascular Necrosis
Because AVN symptoms overlap with other hip conditions, an accurate diagnosis requires a combination of clinical evaluation and imaging tests.
Imaging Techniques
MRI (Magnetic Resonance Imaging): The most sensitive method for detecting early-stage AVN, even before symptoms appear.
X-rays: Used to assess bone structure and any visible changes, but may not detect early AVN.
CT (Computed Tomography) Scans: Helpful for evaluating bone damage and joint integrity.
Bone Scans: Can be useful in certain cases to identify areas of reduced bone activity.
Treatment Options for Avascular Necrosis
The goal of treatment is to preserve joint function and relieve pain while preventing further bone damage. The best approach depends on the stage of the disease and the extent of bone deterioration.
How Physiotherapy can Help this Condition
Pain management: applying ice to the affected area can help to manage the pain.
Activity modification: reducing weight bearing activities that increase stress on the affected joint.
Exercises to preserve joint range of motion and to strengthen the muscles around the hip.
Lifestyle modifications: Advice on weight management and reducing high-impact activities, for example.
If surgery is indicated, physiotherapy will be part of the rehabilitation process to help regain function, range of motion, and strength.
Surgical Options
For more advanced cases, surgical procedures may be necessary:
Core Decompression: A minimally invasive technique where small holes are drilled into the femoral head to relieve pressure and stimulate new blood vessel growth. In some cases, bone grafting may be used to promote healing.
Osteotomy (Bone Reshaping): This procedure redistributes weight away from the damaged portion of the hip joint to preserve function.
Total Hip Replacement (THR): In severe cases where the femoral head has collapsed, a hip replacement may be the most effective long-term solution.
While not all cases of AVN can be prevented, certain lifestyle modifications can help lower the risk:
Limit alcohol intake to reduce fat buildup in blood vessels.
Use corticosteroids cautiously under medical supervision.
Manage underlying health conditions such as diabetes or blood disorders.
Maintain a healthy weight to reduce joint stress.
Seek prompt treatment for hip injuries to prevent complications.
If you are experiencing persistent hip discomfort, early intervention is key to preventing irreversible joint damage. A thorough assessment by a physiotherapist or orthopaedic specialist can help determine the most suitable treatment plan for your condition. Melbourne Physio Clinic is dedicated to providing expert care and evidence-based treatment strategies to support your hip health and mobility.