Hip
Avascular Necrosis of the Hip
In avascular necrosis, the bone in the ball at the top of the thigh bone dies because its blood supply has been cut off or reduced. It is a blood supply problem, not wear and tear. Caught before the joint surface collapses, it can sometimes be treated without a replacement. Caught after, replacement is usually what restores the joint.
By appointment only, at Kharar (Mohali) or Solan. Your confirmation says which.
What causes it
In many people no clear cause is ever found. The recognised risk factors are long-term or high-dose steroids, heavy alcohol use, sickle cell disease, smoking, and a previous fracture or dislocation of the hip that damaged the blood supply directly. It is also more common in India than in many other countries, and nobody is entirely sure why.
It usually affects people in their thirties to fifties, younger than the usual age for hip arthritis. The other hip is often affected too, sometimes before it causes any symptoms, so once one side is diagnosed the opposite hip is usually imaged as well.
When it needs seeing sooner
- Suddenly being unable to bear weight, which can mean the bone has collapsed or there is a fracture as well
- The hip is hot and painful and you feel unwell or feverish
- A sudden, marked change in how the leg sits or moves
- Pain with fever, night sweats or unexplained weight loss
Short of those, groin pain with any of the risk factors above needs a routine consultation. Do not wait to see if it settles: how early this is caught changes what can be done about it.
How it gets assessed
The pain is usually in the groin and can travel down the front of the thigh towards the knee, like other hip joint pain. Once it has progressed, it can hurt even at rest. The examination looks at rotation in particular, often the first movement to be affected.
X-rays are often normal in the early stages, and that is the trap. A normal X-ray does not rule this out if the story fits. An MRI is far more sensitive early on. It is the test that picks it up before the bone surface starts to collapse, while the treatment options are still at their widest.
What treatment usually looks like
Treatment depends almost entirely on the stage it has reached when it is diagnosed.
Before the bone surface has collapsed, in carefully selected cases, procedures that relieve pressure inside the bone or support the area can sometimes save the joint and delay or avoid a replacement. Once collapse has begun, those options narrow and can disappear. In ordinary arthritis, watching and waiting is often a reasonable choice. In early avascular necrosis it is not a neutral one.
Once the joint surface has collapsed or arthritis has set in, hip replacement is usually what reliably restores comfortable movement. It works as well here as for any other cause of hip arthritis. The difference is that these patients are often younger than the usual hip replacement patient. Their age is part of the discussion, but it is no reason to rule the operation out.
Common questions
Is avascular necrosis the same as arthritis?
No, though it can lead to it. Arthritis is the joint surface wearing out. Avascular necrosis is the bone underneath dying because its blood supply has failed. Once that bone collapses under ordinary loading, arthritis often follows. They are still different diseases, and their early treatment is different.
What causes the blood supply to fail?
The recognised causes are steroid use, heavy alcohol intake, sickle cell disease, and a hip fracture or dislocation. In a fair number of people none of these is present and no cause is ever found.
Will my other hip be affected too?
It often is, sometimes before it causes any symptoms. So once one side is diagnosed, the other hip is usually imaged as well. If it is affected, it can then be caught at an earlier, more treatable stage, before it starts to hurt.
Can it be caught before the joint collapses?
Yes, and it is the most important thing to know about this condition. An MRI can pick it up well before an X-ray can, and well before the bone surface collapses. That window is when treatment to save the joint is possible. If you have groin pain and any of the risk factors above, get it imaged; do not wait it out.
Related procedures
Where an operation does turn out to be the right answer, these are the ones this problem most often leads to.
Not sure what is causing it?
Finding out is what a consultation is for. Bring any imaging you already have, and any plan you have been given elsewhere. He sees patients by appointment only, in Kharar, Mohali, and on set days each month in Solan.