Are you or someone you love suffering from Avascular Necrosis of your hip or knee and looking for an avascular necrosis specialist?
If you have been told you have avascular necrosis of the hip, the ball of your hip joint has lost part of its blood supply, and a small or large area has begun to die. This is not cancer, and it will not spread through your body. If nothing is done, it slowly gets worse, and over months to a few years the ball can flatten and the joint can wear out.
The hard truth is that the dead bone does not grow back. The good news is that this is treatable at every stage, and if it is caught before the bone collapses, there is a real chance to delay the possibility of getting a hip replacement. But eventually that’s where you are heading.
The bone in the ball of your hip has died in one main spot, and that spot is where you stand on it
Your hip is a ball and socket joint. The ball is the top of your thigh bone, and it is covered by a smooth cap of cartilage. Blood reaches that ball through small vessels that run up the neck of the bone. In avascular necrosis, some of those vessels stop delivering blood, and a wedge of bone inside the ball dies.
The word only means this: bone that has lost its blood supply. The dead bone does not disappear. It stays where it is, weaker than living bone, and it sits under the top of the ball, which is the part that carries your weight when you stand and walk.
When I look at a hip like this early, the cartilage cap on the outside can still look and feel almost normal, while the bone right underneath it has already given way. That matters more than anything else on this page, so I want you to picture it: good cartilage sitting on a foundation that is crumbling.
The first thing to fail is a thin crack that forms just beneath the cartilage. Once that crack opens, the round ball begins to lose its shape and flatten. After it flattens, the socket no longer meets a smooth sphere, the cartilage on both sides wears away, and the joint becomes arthritic.
That is the whole course in order: dead bone, then a crack, then flattening, then arthritis. Everything before the flattening is a hip I may be able to delay a hip replacement on. Everything after it usually becomes a hip that needs replacing. That is why the timing of when you are seen decides so much.
What people describe to me before they ever come in
Most people come to me with pain deep in the groin. It can spread into the front of the thigh, and sometimes it is even felt at the knee, which throws people off. Early on the pain is often there at rest and worse at night, and that surprises people, because they expect a bone problem to hurt only when they use it. As the condition goes on, the pain comes with every step, and the hip stiffens.
People also tell me about the things they have quietly stopped doing without mentioning it to anyone. They have stopped sitting cross-legged. They have stopped squatting down to pick something up. They take the stairs one at a time and lead with the good leg. They have started to limp. The description that makes me suspect this condition in particular is a younger, active person with deep hip pain that is worse at night and far worse than anything a plain x-ray can explain.
The description that makes me look elsewhere is pain that sits on the outer side of the hip and hurts when you press on it, because that is usually inflammation of the tissue over the bone (bursitis), a different problem with a different answer. And because the same process can be going on in both hips at once, I ask about the other side even when only one hip hurts.
You almost certainly did not cause this
The first thing people ask me is whether they did this to themselves. For most people, the honest answer is no. The single most common finding is that we do not identify a clear cause at all, and the condition arrives on its own in someone who was probably prone to it. Where there are causes, the two seen most in this country are long-term use of steroid medicines, called corticosteroids, and heavy, long-term alcohol use.
Other real causes include sickle cell disease and other blood-cell disorders, clotting problems, certain autoimmune diseases such as lupus, some cancers of the blood and marrow, radiation given to treat cancer near the hip, and a previous injury or operation that damaged the hip’s blood supply, such as a broken hip bone.
Deep-sea diving, certain rare storage diseases, smoking, and high blood fats also raise the risk. Most people with this condition are between their twenties and their fifties, which is younger than the age at which ordinary wear-and-tear arthritis usually arrives.
A belief I often have to correct is that ordinary exercise, or a single old bump years ago that healed without trouble, caused this. It almost never did. If you were placed on a necessary course of steroids for another illness, you did nothing wrong by taking the medicine you needed.
I find it useful to sort the cause into one of two kinds, because it changes what I expect to happen next. Some causes are a single event that is now over, such as a hip that dislocated once and went back into place, or a fracture that has since healed. Other causes are a constant circumstance that keeps injuring the bone, such as ongoing steroid use, continued heavy drinking, or a blood disorder that is always present.
If your cause was a single event and years have passed without trouble, your outlook is more settled. If your cause is still acting on the bone, the hip keeps taking hits, and I am more guarded about how it will behave.
What my hands and eyes tell me, and why I still send you for a MRI scan
I examine you first. I watch how you walk, I move the hip through its range, and one of the most useful things I do is simple: I hold your relaxed leg and roll it gently inward and outward while I watch your face, because a hip that is irritated deep inside will catch and ache on that roll long before anything else shows. I feel for where the pain truly lives.
Here is something most pages will not tell you. In early avascular necrosis, my examination is often normal. The hip moves well and does not hurt much to move, even though the bone inside is dying. That normal examination is not a dead end. It is information. It tells me we may have caught this early, while there is still a round ball and good cartilage to protect, and it is the reason I do not rely on my hands alone for this particular diagnosis.
Later, once the ball has begun to flatten and the joint is turning arthritic, the examination changes: the hip loses its range, and that lost range comes with pain. So my hands tell me how far along you are and how much the joint is troubling you. It is the MRI that confirms the diagnosis and measures how much bone has died.
What the MRI shows me, and the one thing it cannot
I start with plain x-rays. Early on these are usually normal, and a normal x-ray does not mean nothing is wrong. That is exactly why the next test matters. Magnetic resonance imaging can find this condition before an x-ray shows anything, and it measures how much of the ball is affected.
If your report used phrases that frightened you, here is what they mean in plain words. A double line sign, or a line of demarcation, is simply the border the body has drawn between the dead bone and the living bone around it. Bone marrow edema means fluid and swelling inside the bone, which usually means the hip is painful.
A subchondral fracture, or a crescent sign, is that thin crack forming just under the cartilage, and it is an important line to have crossed, because it means the ball has begun to fail. Collapse means the ball has lost its round shape. I use the Ficat and Arlet system to stage this, but the one line in it that decides your treatment is plain enough to hold on to: has the ball collapsed yet, or not.
I rarely order a computed tomography scan for this. I use it only when I need to judge how round the ball still is, and I hold it in reserve because it delivers more radiation than the other tests and usually adds little.
Here is what no scan can tell you. It cannot tell you exactly how you will feel, and it cannot put a date on whether or when the ball will collapse. The amount of dead bone in the picture does not line up neatly with how much pain you have or how fast you will change. I treat you, not the film. A worrying scan in a person who walks and works well is watched closely. A modest-looking scan in a person who cannot get through the day is treated.
If we do nothing, here is what happens, and it does not undo itself
I will not soften this. Once a segment of bone in the ball has died, it very rarely comes back to life on its own. A hip in which this condition reverses with rest or with time is close to unheard of. It has been reported in literature, but I haven’t seen it personally, and I suspect how accurate the diagnosis was if it really reversed.
Most of these hips slowly get worse in the order I described: the dead area weakens, the crack forms, the ball flattens, and the joint becomes arthritic. What differs from person to person is the speed. A hip whose cause was a single event that is now over may sit quietly for a long time. A hip whose cause is still acting on it tends to move faster, and it is harder to predict.
One point decides everything, and it is the collapse of the ball. Before the ball collapses, I have a real chance to relieve the bone and try to keep your own hip. After it collapses, the joint-saving options mostly close, and the honest conversation becomes about replacing the hip.
That is the line past which waiting has cost you something you cannot get back. You would know you are approaching it: the pain climbs, the hip stiffens and loses its range, and a new limp settles in and does not leave. If those things are happening, do not wait to be seen.
What I do first, while the ball is still round
Everything in this section is for a hip that has not yet collapsed, because that is where there is something to save. My first goal is not the operating room-but it gets to that very quickly. The first thing to do is to take the load and the pressure off the dying bone and to deal with whatever is still injuring it.
If you are taking steroids for another condition, I work with the doctor who prescribed them to see whether the dose can safely come down, and we never stop a medicine you need without their agreement. If heavy alcohol is the driver, cutting it back genuinely changes the picture. If you smoke, stopping helps your bone heal. As a temporary measure, I have you take weight off the hip, often with a cane or a crutch on the affected side, to spare the failing bone while we decide.
Some medicines are used around this condition, and I want you to understand them honestly. Bone-protecting drugs, cholesterol-lowering drugs, and blood thinners are mostly used to treat the problems that come with the condition, and they can help alongside treatment, but none of them brings dead bone back to life.
For a small area of dead bone found early, in a person with few or no symptoms and a cause that is now over, watching the hip closely with repeat scans and controlling the risk factors is a reasonable path, and I will tell you plainly if you are in that group. But most established dead areas do not repair themselves, so watching alone is rarely the whole answer.
When the bone is at real risk of collapse and there is still a round ball to protect, I move to the operation most likely to let you keep your own hip, which I describe below.
What I have stopped using for this, and why
Naming what I do not do is as honest as naming what I do, and wherever I differ from what some other surgeons do, I owe you the reason.
I do not use invasive tests to make this diagnosis, such as measuring the pressure inside the bone, taking a core sample of it, or injecting dye to study its veins. My examination, the x-ray, and the magnetic resonance imaging give me what I need, and these tests add discomfort and risk without changing my plan.
I do not place a metal rod, made of a porous metal called tantalum, into the ball at the time I relieve the pressure, which some surgeons do to try to prop the bone up. My reason is direct: if that ball later collapses and needs to be replaced anyway, the metal makes the replacement harder and can shed metal debris into the joint. I would rather not leave something behind that complicates the operation you may still need.
I do not perform a rotational osteotomy, an operation that cuts the thigh bone and turns the dead part of the ball away from where you stand on it. It has been described for many years, but its good results have been hard for others to reproduce reliably, and it makes a later hip replacement considerably more difficult. That is a trade I do not think is worth making.
If a ball has already collapsed and the joint is arthritic, I do not offer to replace only the ball, and I do not fuse the joint solid. For a surgeon who is comfortable with total hip replacement, replacing the whole joint gives a more reliable result than a partial replacement or a fusion, and it keeps the hip moving.
I do not rely on the machine-based treatments sometimes offered for this, such as pulsed electromagnetic field therapy, hyperbaric oxygen, or shockwave. The evidence behind them is weak, and I will not have you spend time and money on something the studies do not support.
When I start talking to you about replacing the hip
Here is my own threshold, not the general rule. As long as the ball is still round and has not collapsed, I steer toward saving the joint, and I mention a replacement only as the thing we are trying to avoid for the time being. I start the conversation about a total hip replacement when the ball has collapsed, when the joint has become arthritic, and when the pain and stiffness are limiting the life you actually lead: your walking, your sleep, your stairs, your work.
Remember that the salvage procedures are not going to prevent hip replacement, but they will delay the onset of arthritis in the right patient selection.
What makes me tell you to wait: a small dead area found by chance, with a cause that is over and a hip that still works well. Watching that hip is often the right move. What makes me tell you it is time now: pain that is climbing, a ball at real risk of collapse where the joint-saving operation still has a chance, or a ball that has already gone and left you with a painful, arthritic hip. I do turn people away from surgery when the film looks worse than the person feels, because I treat the person and not the picture. The decision is never made on the scan alone.
The two operations I actually do for this
The first is core decompression with your own biology added, and it is the joint-saving operation for a ball that is dying but has not yet collapsed. I drill a narrow channel up into the dead area to relieve the pressure inside the bone and to start fresh bleeding and healing. Then I add biology to improve the odds: I draw your own repair cells, called stem cells, from your pelvis, concentrate them, and place them into the dead area along with a protein that tells bone to grow.
The number of repair cells I can gather varies from person to person, and it is lower in older people and in smokers, so I take as many as your body will give. Recovery centers on keeping your weight off the hip with crutches for a period of weeks while the drilled bone heals, and I set your exact milestones for your hip. I do this operation, and I will be straight with you about it: it does not always stop the condition from progressing, and how well it works depends on your stage and your cause.
Postoperative image after core decompression and injection of a stem cell harvest, published on this site as Left Hip Core Decompression with Stem Cell Injection in a 45-year-old male with Avascular Necrosis of the Hip. Look at this one as the alternative to replacement in a young hip caught early. An x-ray from one of my own patients. Identifying information and the embedded file data have been removed.
The second is total hip replacement, and it is for a ball that has already collapsed and a joint that has become arthritic and painful. I remove the worn ball and the damaged surface of the socket and replace them: a metal stem set into your thigh bone, a metal shell lining the socket with a smooth plastic liner inside it, and a new ball that turns on that liner.
The stem I use has a roughened, porous surface that your own bone grows into and grips, so it holds without cement. It suits people whose pain and stiffness are limiting their daily life. I do this operation, and it is reliable for relieving pain and restoring walking.
There is one honest point I make to everyone, and I would rather you hear it from me now: hip replacements done for avascular necrosis have, over the years, shown a somewhat higher rate of loosening and failure than replacements done for ordinary wear-and-tear arthritis. That is exactly why the implant and the technique matter here, and it is why I choose the implant I do. It is described in full on its own page.
What you get back, and what you do not
If the joint-saving operation works, you keep your own hip, and you have slowed or avoided a replacement. If the ball still collapses afterward, you have lost some time, but you have not burned a bridge: you can then have the replacement. People fear that trying to save the hip first will ruin their chances later. It does not-if the correct procedure is done.
After a total hip replacement, what you get back is the thing you came in without: walking without that deep pain, sleeping through the night, managing stairs, getting through an ordinary day. What you do not get back is a hip built for pounding. The common-sense trade is that very high-impact activity, the kind that hammers the joint, comes off the list for good, to protect the replacement.
A hip replacement is not forever, but it lasts a long time. In large national studies that have followed these replacements for decades, most are still working well after twenty years, and a majority are still working at twenty-five. For the reason I gave you above, a hip replaced for avascular necrosis may not run quite as long as one replaced for ordinary arthritis, which is another reason I would rather save your own hip when there is still a chance to.
How quickly you return to work depends on what your work demands of the hip, so I will be specific about the jobs I actually treat. If you teach, you can usually return to a modified day fairly soon and to a full day on your feet once standing is comfortable. If your work is at a desk, you are generally back within a few weeks.
The physically demanding trades take longer, and full, unrestricted duty is the last thing to come back. Construction workers, who lift, kneel, and climb, and transit and railroad workers, who work on uneven ground and climb in and out of equipment, are often three months or more from full duty, with lighter duty before that.
Police officers and firefighters, who run, carry, restrain, and climb ladders, come back to full, unrestricted duty later still, and light or administrative duty usually comes first. If your case is a workers compensation or no-fault claim, know that your return-to-full-duty date is often set with your employer and the insurance carrier, not by the two of us alone, and light duty usually comes well before full duty.
And if you live in a walk-up or face a long commute, plan the first weeks around this: stairs and time on your feet are the two things that are hardest early, and a little arranging at home makes a real difference.
The questions people ask me in the room
Is this the same as degenerative arthritis?
No. It is a different problem, and it comes before arthritis rather than being arthritis. Avascular necrosis is bone dying from a loss of blood supply. If the ball collapses because of it, the joint then wears out and becomes arthritic. That order is the whole reason it is worth catching early, while the ball is still round.
Will my other hip get it too?
It can, and it’s very likely and it is worth checking, because in a good number of people the same process is quietly going on in the other hip before it ever hurts. The risk to the other side is higher when the cause is a constant one, such as ongoing steroids or a blood disorder. I routinely scan both hips, even if patients come to me with pain in one hip that has avascular necrosis.
If I just stay off it and rest, will the bone heal itself?
Once a segment of bone has died, it does not come back to life on its own, and rest alone will not rebuild it. Staying off it can ease your pain and is worth doing while we plan, but do not count on rest to fix the bone.
I do not have much pain. Do I still need to do anything?
Possibly yes, and that is exactly the point of catching this early. A hip can be at real risk of collapse before it hurts much. If your dead area is small and your cause is over, we may simply watch it closely. If it is at risk, the time to act to save the joint is before it collapses, not after.
Can I keep working and exercising?
Usually you can keep working, and gentle, low-impact movement is fine and good for you. What I ask you to drop is the high-impact loading, such as running and jumping, that pounds the weak spot in the ball. We match what you do to how far along your hip is.
Will my children get this?
Avascular necrosis is not simply passed down like eye color. Some of the conditions that can cause it, such as certain blood disorders, do run in families. If a family condition is behind yours, that is worth your family knowing about, but having this hip does not mean your children will have it.
Do I need to lose weight before anything is done?
For the joint-saving operation, weight is not the deciding factor. For a hip replacement, getting your weight and your general health into good shape beforehand is worth the effort. It is something we work on together, not a reason I will refuse to help you.
This page is general information about a condition. It is not medical advice for any one person, and it does not replace being examined.
Dr. Karkare is a leading orthopedic surgeon in New York City with multiple locations on Long Island. He provides patients with the most effective and advanced treatments for avascular necrosis.
His extensive experience and in-depth knowledge of bone and joint health issues mean he is uniquely positioned to help patients understand the cause of their condition while creating customized solutions based on each patient’s unique needs and health profiles.
If you’ve been experiencing any type of joint or bone pain or weakness, the first step is to evacuate toward ensuring you get the best and most appropriate care for complete recovery and optimum health.
