Avascular Necrosis of the Hip (AVN)
Avascular necrosis (AVN) of the hip occurs when the blood supply to the femoral head (the ball of the hip joint) is reduced or lost. Without blood, the bone tissue weakens and can collapse, leading to pain, stiffness, and arthritis.
Causes
AVN can occur due to:
- Trauma, such as a hip fracture or dislocation
- Long-term steroid use
- Excessive alcohol intake
- Certain medical conditions (e.g., sickle cell disease, autoimmune disorders)
- In some cases, no clear cause is identified (idiopathic).
Anatomy
The femoral head relies on delicate blood vessels for nourishment.
If these vessels are damaged or blocked, the bone in the femoral head becomes fragile and may lose its normal round shape, affecting joint function and causing cartilage breakdown.
Avascular Necrosis of the Hip (AVN)
Symptoms
Common symptoms include:
- Deep pain in the groin or buttock
- Pain that worsens with weight-bearing or activity
- Stiffness and reduced hip movement
- Limping or difficulty standing for long periods
- Symptoms may develop gradually or progress rapidly.
Diagnosis
Your doctor will assess your hip and walking pattern.
Investigations may include:
- X-rays, which may be normal early on
- MRI scan, which is the best way to detect early AVN and assess severity.
Treatment
Treatment depends on the stage of the condition:
- Early AVN (before bone collapse) may be treated with:
- Activity modification and protected weight-bearing
- Physiotherapy
- Medications to support bone health
- Core decompression surgery, sometimes with bone grafting or biologic support to improve blood flow
- Advanced AVN (when the femoral head has collapsed) is usually treated with total hip replacement to restore function and relieve pain.
Recovery
Recovery depends on the stage of disease and treatment:
- Early-stage management may slow or stop progression.
- Hip replacement offers excellent pain relief when AVN is advanced.
Possible Complications
If untreated, AVN can lead to:
- Collapse of the femoral head
- Severe arthritis of the hip joint
- Persistent pain and loss of mobility.
When To Seek Help
See your doctor if you have:
- Persistent hip or groin pain
- Difficulty walking or bearing weight
- A history of hip injury or steroid use with new hip symptoms.
