Avascular Necrosis of The Hip: What you need to know

What is Avascular Necrosis of Hip?

Avascular necrosis of the hip is a bone disorder in which the cells of the thigh bone die due to the lack of blood. The condition affects the head (ball) of the femur (the thigh bone). Without blood, the head of the femur becomes flat and deformed with tiny breaks in it—eventually leading to its collapse. Avascular necrosis can affect anybody but commonly affects people below fifty years of age and is associated with steroid use and excessive alcohol intake.

What are the causes of Avascular Hip Necrosis?

The causes of reduced blood supply to the head of the femur include:

Trauma or injury of the hip joint such as fracture or dislocation of the femur
Blocking of blood vessels due to the fat deposition
Diseases of the blood such as sickle cell anemia can also lead to reduced blood flow

Certain factors increase the risk of developing avascular necrosis of the hip, such as:

Steroid medications: These increase lipid content in the blood
Excessive alcohol intake: It also increases fat deposition in the blood
Cancer therapy and many medical conditions such as Gaucher disease also increase the likelihood of avascular hip necrosis.

What are the symptoms of Avascular Hip Necrosis?

In its early stages, the disease does not cause any symptoms. Once the symptoms appear, they worsen over time. Pain is a prominent symptom. It has the following characteristics:

Pain when putting weight on the hip initially
As the disease progresses, pain may even be felt when lying down
Pain in the groin or buttock that radiates into the thigh and knee
Pain that limits hip movements

If the disease remains untreated, the pain may make it virtually impossible to move.

How to diagnose Avascular Hip Necrosis?

Your doctor will make the diagnosis based on:

Symptoms of pain, tenderness, and joint stiffness
Medical history such as using steroid medications, taking excessive alcohol, or any past hip fracture or dislocation
Physical examination to check for tenderness and the range of joint motion. For this, your doctor will move your leg through different positions.
X-rays to check for the severity of the disease. These reveal bone changes as the condition progresses.
MRIs and CT scan to help detect changes in the bone due to avascular necrosis in the early stages of the disease

What’s the prognosis of Avascular Hip Necrosis?

The prognosis of AVN of the hip depends on the early diagnosis. The condition takes months or even years to heal. Most people have to wear splints or braces for many months. More than fifty percent of the cases require surgery.

What are the treatments of Avascular Hip Necrosis?

Your doctor may recommend the following treatments of avascular necrosis of hip depending on stage:

Over-the-counter pain medications such as naproxen to relieve pain
Blood-thinning drugs such as warfarin as well as cholesterol-lowering medications to prevent blood vessel blockage
Rest and reducing or modifying activities to prevent tiny breaks in the head of the femur. The doctor may also recommend splints or braces to immobilize the hip joint.
Physical therapy to strengthen muscles and restore range of hip motion

Surgery is the last resort and depends on many factors. Surgical options include:

Core decompression: It involves removing part of the inside of the femur to reduce pressure and allow the formation of new bone tissue and blood vessels
Bone graft: It involves replacing the damaged bone with healthy bone
Osteotomy: It involves reshaping of the bone to relieve stress
Total joint replacement: If the bone has collapsed or other treatment options are not working, the doctor may recommend replacing the total joint.

What are non-operative interventional managements?

The following interventional managements may be tried before surgery?

Platelet rich plasma injection to attempt a regeneration
Before replacement, nerve blocks with radiofrequency or cryoablation technique are altenatives in late stage when there is deformity.