Your MRI report says "avascular necrosis of the femoral head", or "AVN, right hip", followed by phrases like "marrow oedema", "double-line sign" or "subchondral collapse". Most people read it alone, late at night, and fear the worst. A report is not a sentence; it is a map. It tells your physician how much bone is affected and whether the ball of the hip is still round — and an early report is the strongest reason for hope, because in the majority of the patients we treat for early-stage AVN, progression is arrested.
Why MRI is the key test for AVN of the hip
An ordinary X-ray can look completely normal in early AVN. MRI is the gold standard: it can detect AVN in its earliest stages, often before any collapse of the bone. That is why we investigate persistent hip pain thoroughly rather than waiting for X-ray changes to appear.
X-rays, CT scans and bone scans each add information at different stages. An X-ray of the pelvis shows the shape of the ball and the joint space; a CT scan shows fine cracks in the bone more clearly when the doctor needs to know whether collapse has begun.
The words on an AVN MRI report, explained
These are the phrases patients most often ask us about. Your report may use only some of them.
- Avascular necrosis / osteonecrosis of the femoral head. An area of bone in the ball of the hip has lost its blood supply. Both names mean the same thing.
- Bone marrow oedema. Swelling, or fluid, inside the bone marrow. In AVN it is an early sign of bone stress, and it often appears on MRI before anything shows on an X-ray. It is also often the source of the deep groin pain.
- Double-line sign. A characteristic pattern on MRI, a line around the affected area, that is highly specific to AVN. It is the radiologist's way of saying "this is AVN and not something else".
- Geographic or wedge-shaped lesion; percentage or extent of involvement. How large the affected area is, and which part of the ball it sits in. The larger the area and the more it lies under the weight-bearing surface, the higher the risk of collapse.
- Sclerosis and cysts. Areas of hardened bone and small hollows that show on X-ray as the condition moves into Grade 2. The ball is still round at this stage.
- Crescent sign / subchondral fracture. A crescent-shaped line just beneath the joint surface: the bone there has begun to collapse. It marks the move into Grade 3.
- Loss of sphericity; flattening of the femoral head. The ball is no longer perfectly round.
- Joint space narrowing; secondary osteoarthritis. The cartilage between ball and socket is thinning and arthritis has set in — the picture of Grade 4.
- Joint effusion. Some fluid in the hip joint, commonly seen with an irritated, inflamed joint.
- "Contralateral hip" or "left hip also shows…". The other hip has changes too. AVN often affects both hips, sometimes before the second one hurts.
How your report sets the grade of AVN
From the MRI and X-ray, AVN of the hip is placed on a scale. The most common is the Ficat-Arlet staging, Grade 1 to 4; some reports use the ARCO system, which is similar.
- X-ray normal; MRI shows marrow oedema or an early lesion — What it usually means: Bone structure intact; Grade: Grade 1
- Sclerosis or cysts on X-ray; head still round — What it usually means: Changes visible, no collapse; Grade: Grade 2
- Crescent sign, subchondral fracture, early flattening — What it usually means: Collapse has begun under the surface; Grade: Grade 3
- Flattened head, joint space narrowing, arthritis — What it usually means: Advanced collapse; Grade: Grade 4
If the grade is not written on your report, ask for it, and on which scale. It is the single most useful number for every decision that follows.
What your MRI does not tell you
A scan shows the bone. It does not show how the bone will respond to treatment, why the blood supply failed, or how much your body can still heal. Two people with similar scans can have very different outcomes, depending on how early treatment begins and whether the causes are addressed.
That is why, at AVN Arogya, the report is a starting point. Along with the scans, a panel of blood tests — including inflammation markers, cholesterol, clotting studies, homocysteine, blood sugar, liver and kidney function, and vitamin D3 and B12 — helps us understand what contributed to your AVN, so each factor can be addressed. We also record a Harris Hip Score, a pain score and a quality-of-life questionnaire before and after treatment, so progress is measured, not assumed.
What can be done at each grade of AVN
The grade guides the treatment. Patients diagnosed in Grades 1 and 2 have the strongest chance of preserving the hip without surgery. Even in Grade 3, treatment can relieve pain, improve function and support preservation of the joint. In Grade 4, a hip replacement may be an appropriate option, especially if the patient's age is greater than 60 and in others the goals is to be able to postpone surgery for as long as possible. Thankfully, many of our Grade 4 patients gain meaningful improvement in function and pain and are able to postpone and avoid surgery for many years.
Our treatment works to reduce inflammation, improve blood flow to the hip, strengthen the bone by supporting bone metabolism, and remove what gets in the way of the body's own healing. Every programme is designed personally by your physician for your grade, the risk of collapse, your age and how inflamed the hip is.
Repeat MRI: how we track healing
After your inpatient programme, a repeat MRI at six months tracks the bone objectively. We arrange an expert radiological opinion and a functional evaluation before treatment and again a year after, to confirm that progression has stopped. In the majority of the patients we treat for AVN, the follow-up MRI shows that progression has been arrested. Occasionally, in early grades, we have even seen the damage reverse on repeat MRI; we do not promise this, but it shows what the body can do.
Frequently asked questions
My X-ray is normal but the MRI shows AVN. Which is right?
Usually the MRI. In early AVN the X-ray is often normal while the MRI already shows changes in the bone marrow. This is good news in one sense: it means the AVN has been found early, when there is most to preserve.
Does "bone marrow oedema" mean I have AVN?
Not always. Marrow oedema can have other causes, such as a stress injury, so your physician reads it together with the rest of the scan and your symptoms. In AVN it is an early sign of bone stress.
Should I get an MRI of both hips?
When it is clinically indicated, yes. AVN often affects both hips, and an MRI can find early changes in the other hip before they cause pain.
Can I send my MRI to AVN Arogya before visiting?
Yes. You can upload your MRI and reports for a preliminary evaluation, and a physician will tell you honestly what they show. Send the actual images or CD if you have them, as well as the written report.
Seek urgent care if your hip pain suddenly becomes severe, if you suddenly cannot put weight on the leg, or if the hip is hot and swollen with a fever.
For an honest second opinion and a chance to avoid unnecessary surgery, consult an AVN Senior Physician and bring your MRI. Read about Ayurvedic treatment for avascular necrosis of the hip, or book a consultation — you can send your MRI and reports in advance.