Avascular necrosis (AVN) of the femoral head is trauma to a small artery that supplies essential nutrients and oxygen to the femur head, loss of blood supply sets in motion a rapidly deteriorating picture. It all starts with hip pain in the front in the crease of your groin. Ignoring this deep hip pain will have serious implications for the simplest of movements. You either end up in constant pain, avoiding anything that involves putting weight on your leg, or in need of a good surgeon to operate on your hip. However, this ending isn’t inevitable, because there is so much that can be done before you reach this critical point.

Unfortunately surgery is more common, as patients wait too long, and by the time we diagnose it – there’s no time to try less aggressive ways to fix it.

Hip joint anatomy

Your hip joint allows you to walk. Your hip is a ball and socket joint and is one of the most mobile joints in your body. The head of the femur, also known as the femoral head, is the ball part of your hip joint and is located at the top of your thigh bone.

The anatomy of your hip allows a lot of mobility, but all this mobility leaves it unstable and vulnerable to injury. Having a hip that could pop out simply wouldn’t cut it. That’s where the socket part of the joint comes in. The socket is the cup that houses your femur head, its part of your pelvis and can be found above the head of the femur. There’s also a cartilage ring, almost like a seal-washer, around the socket that keeps your hip joint in place. Strong ligaments encapsulate your hip that improves the stability of your hip. On top of all that, you have some of the biggest and strongest muscles in your body around your hip to give extra support and do all the heavy lifting.

Of course, any joint also needs nerves to carry messages and blood supply to transport nutrients. There is a complex network of nerves around your hip joint, connecting your lower back to your leg. Similarly, the main arteries and veins branch out at your hips and pelvis to form an intricate web of blood vessels. In adults, the blood supply to the femoral head comes from the medial and lateral circumflex arteries.

What is avascular necrosis of the hip?

When we talk about the vascular system, we all think of arteries and veins. In a healthy hip joint, blood vessels supply oxygen and nutrients to the femoral head, ensuring its proper function and maintaining the integrity of the bone. Avascular necrosis of the hip occurs when this blood supply is interrupted. Decreased blood flow to the head of the femur means that the necessary nutrients can’t reach the bone tissue, resulting in cell death, or necrosis.

I have Avascular Necrosis (AVN). How did it happen?

Avascular necrosis occurs whenever there is insufficient blood supply to bone. Bone tissue is continuously remodeling, maintaining a fine balance of new bone being made and old bone being reabsorbed. Unfortunately, injury, trauma, or overuse disturbs this delicate balance between the breakdown and build-up of bone. In the case of avascular necrosis of the hip, the normal supply of blood to the head of the femur is interrupted.

When this happens, bone is absorbed at a faster rate than new bone forms. Also, the new bone is of poor quality, as blood vessels are unable to provide essential nutrients to form strong bones. The organized, hard, solid compact bone structure becomes disorganized, soft and weak. Unable to effectively transmit force through the bone, leading to excessive wear & tear on the bone structure itself. This causes weak points in the bone and injuries like fractures appear with low velocity movements like just standing up. This accumulation of microtrauma heals poorly, if at all.

Causes of Avascular Necrosis (AVN) of the femoral head

Vascular structures are quite flexible and elastic, able to be contorted and stretched into splits, but sudden twists and falls tear, rupture or burst the arterial walls. Hip injuries like fractures and dislocation cuts through the blood vessels. Any form of direct trauma to your hip puts you at risk of developing avascular necrosis of the femoral head.

Sometimes the blood vessels have an underlying structural problem within its walls that makes it more rigid, like excessive alcohol use, steroid use such as cortisone or clotting disorders. On the other hand, the wall of the blood vessels become frail and leaks blood like in chronic anti-inflammatory use and radiation therapy that destroys the cell lining, and even cancers.

    Symptoms of AVN of the hip

    Tests you can do to see if you have avascular necrosis of the femur

    • Sit upright on a chair
    • Place one foot slightly behind the other
    • Bend forward and come up into a standing position
    • Pain or tension in your hip, groin or buttocks at any point during these movements may indicate that you have a hip joint issue and possible hip avascular necrosis
    • Put one leg up on a step.
    • Climb up with the full weight on the one leg 10 times.
    • Control the ascent and decent to 5 sec interval (very slow)
    • Hold on to support or a rail for safety.
    • Repeat this movement to the other side.
    • Pain or tension in your hip, groin, buttocks or leg could indicate hip pathology and possible avascular necrosis of your hip.
    • Stand comfortably with your feet slightly apart and your arms next to your sides.
    • Hold on to a chair or support for balance.
    • Stand on one leg with the knee completely straight.
    • Rotate your upper body clockwise and anti-clockwise over the standing hip 10 times.
    • Ensure you rotate all the way until you feel there’s no more hip joint movement possible.
    • Pain or discomfort in the hip, groin, buttock, or leg may indicate hip joint involvement and possible hip avascular necrosis.
    • Do not try this test if the previous tests already cause moderate or severe pain.
    • Start by standing close to a chair for support.
    • Crouch down as low as you can, letting your heels lift off the floor if you need to.
    • Hold this position for 30 seconds, and then get up.
    • If you have groin or deep buttock pain in this position, it’s definitely a good idea to get an expert diagnosis for your hip pain.
    • With avascular necrosis of your hip, you’ll be able to go into the position, but getting out of it is a daunting task.

    Remember, these are only screening tests to help you get an idea of the state of your hip. These are normal movement your hip should be able to do, and pain with any of these movement require experienced physiotherapists to confirm the source of the problem and give you a proper diagnosis and treatment plan.

    Different stages of necrosis of the femoral head

    Early Stage

    At first, as the blood supply to the bone decreases and bone degeneration starts, there may be no symptoms whatsoever. Most days you are not even aware of anything out of the ordinary and life continues as normal. However standing for long periods becomes uncomfortable and you need to keep shifting your weight from leg to leg. Walking for long distances becomes more difficult as your hip and buttocks ache and become tired. Fortunately, resting helps and your discomfort disappears almost immediately.

    Your main symptom is an ache or discomfort, so you can still get a good night’s sleep during this stage. On occasion, you may need over-the-counter pain medication, but in general small lifestyle changes relieve all your symptoms, and the pain is still manageable.

    Intermediate Stage

    As the necrosis of your hip progresses, you must walk shorter and shorter distances before your pain starts. The pain goes from mild to moderate and interferes with activity. Where the initial pain was only in your groin, it starts spreading to your hip, buttocks, or lower back. At times the pain spreads into your thigh or down to your knee.

    Standing periods become shorter and weight shifting to the other side does not offer as much relief anymore. You start looking for places to sit down and rest your hip before standing up again. Some days you won’t want to leave the house without something to lean on, like a walking stick or crutch. Without it, a long walk causes a severe flare-up in your pain. You start anticipating pain and being able to predict which movements is going to make it worse. Hesitating at a “too high” step.

    Symptoms progress from a vague discomfort to a continuous ache in your groin, hip, or buttock. Resting still provides pain relief, but it takes longer for the pain to settle and the ache doesn’t really change. Your daily routine starts to change because you need to rest more often and you’ll start to avoid chores or hobbies that make your hip pain worse.

    Sleep becomes interrupted as your hip wakes you up when you turn around in bed. Sleeping on the painful hip is limited to short periods and you eventually change your sleeping position, with the help of trusty cushions, you’re able to prop yourself up into a manageable position, as long as you don’t need to get up to go to the bathroom during the night…

    At this point, you always have some sort of pain and anti-inflammatory medication nearby to manage the pain. Dependency and reliance on medication strength becomes a problem.

    Final Stage

    The ache progresses to a constant sharp, stabbing pain in your hip, groin, or buttocks and spreads down your thigh more often.

    Walking is only possible when you have something to hold on to, so you will start to use a walking stick or crutches most of the time. Leaning onto a trolley when doing grocery shopping is a must. Pain flares with the first step. You’ll start to feel unsure or scared to put full weight on the leg as the hip may collapse and give way.

    Standing causes pain and you are always looking for ways to take pressure off the leg, like leaning against a table or wall. Pain intensity rises quickly the longer you stand.

    When you reach this stage of AVN of the femoral head, you will have constant, gnawing pain in and around your hip. Resting positions don’t give you much relief anymore and your sleep is poor, if any. It is too painful to sleep on your side and you often wake during the night. Finding a comfortable sleeping position becomes more and more difficult.

    Even though you’ll be using stronger pain and anti-inflammatory medication by now, they have little or no effect on your pain. Frustration is at its peak, and irritability is normal given the constant regression you’ve experienced until now. The worst thing you can do is just leave it and hope it start healing by itself, it’s long past normal healing and requires external hip treatment. Wake up and start doing something about it.

    Physiotherapy diagnosis of avascular necrosis of the hip

    Having constant deep hip pain is really draining and progressively changes your life completely. Apart from the frustration and irritation, there’s still hope, you don’t have to walk this difficult path alone. Physiotherapists are experts in joint function and love nothing more than getting to the root of a problem to find ways to solve your problem. This requires in-depth knowledge and understanding of hip anatomy and biomechanics. Avascular necrosis is a blood supply problem in your hip, so it is essential that your therapist has a thorough understanding of the specific anatomy and pathology. With us, you will be in good hands!

    With our extensive subjective and physical evaluation, we identify which structures are involved and how bad your problem is at the moment. If further investigations are required, we will refer you for the appropriate tests and discuss the findings with you. Once we have all the information and given a proper diagnosis, we can start with a treatment and rehabilitation program that addresses all the relevant structures to return you to a pain-free and active state. This is not only to threat your hip but also looking at other areas that’s compensated.

    Your therapist guides you through the whole process. It is important that you know what to do, when to do it and also what not to do. Hip– and groin pain is something we see often and we know how to treat it but your problem is unique to you and that is why it is essential to work with an experienced physiotherapist.


    An MRI scan is still the best for the diagnosis of avascular necrosis of the hip. It detects the early stages of bone degeneration better than an X-ray. The MRI also detects bone marrow changes as well as bone edema and sclerosis.

    If your physiotherapist suspects avascular necrosis or other hip joint deterioration, you will be referred to the right specialist.


    X-rays show deterioration of bone in the hip joint which can indicate avascular necrosis. It also shows the integrity and alignment of joints in your hip, pelvis, and spine. This gives us an overall idea of all the relevant structures influencing your hip pain.

    Your physiotherapist will refer you for x-rays if necessary.

    Diagnostic ultrasound

    Ultrasound investigation is most useful to see what is happening with the soft tissue structures involved around the hip joint. The imaging isn’t deep enough to visualize the joint, so it is not the investigation of choice if we suspect avascular necrosis of the hip. If there is suspicion of other structures involved, your physio will refer you.

    Bone Scan

    This is a nuclear imaging technique where a small amount of a radioactive substance is injected into the bloodstream. The material flows to the area being investigated and can show the blood flow in the bone as well as cellular activity. It is a very good test to determine the cause of bone pain and inflammation and is used to pick up bone disease and tumors.

    If your physiotherapist suspects avascular necrosis or other hip joint anomalies, you will be referred to the right specialist.

    Why is my deep hip pain not going away?

    Avascular necrosis of the femoral head is a condition that gets worse over time if you leave it undiagnosed and do not get the correct treatment. As the integrity of the bone deteriorates, there is inflammation and swelling of the bone and surrounding tissue. Your hip joint will not be able to take as much pressure due to pain, so your body starts to compensate and adapt, meaning other structures are taking abnormal strain as they try to help out your aching hip. Usually its these adaptive mechanisms that kick in causing the pain to move around a lot, and difficult to pinpoint the pain.

    The healthy hip hip joint is made to move, your body produces a lubricant inside the joint that helps you move without pain. However, as you move around less and less due to the pain, this lubrication diminishes and the joint “dries out”. Now you’re stuck in a cycle of pain and stiffness. At the same time, the muscles around your hip become weaker and the capsule becomes more stiff due to lack of use, creating abnormal movement patterns. This results in even more stress on your already painful hip joint.

    What NOT to do

    • Continuous use of anti-inflammatory medication.

    • Relying on pain medication to get through the day.

    • Force your hip to move through the pain.

    • Impact exercises such as jogging or skipping.

    • Ignore the pain.

    What you SHOULD do

    • Listen to the body; rest when your pain flares.

    • Keep on moving within the limits of your pain.

    • Get up from behind your computer every 20 to 30 mins.

    • Make an appointment to get the correct diagnosis and treatment plan.

    Making it worse

    • Walking for prolonged periods.

    • Walking downhill or on uneven terrain.

    • Sitting in low seats or chairs.

    • Carrying your child/grandchild on your hips.

    • Running.

    • High impact exercises like skipping, jumping and running.

    • Wearing high heels.

    • Stretching through the pain.

    • Prolonged sitting.

    Problems we see when patients come to us with avascular necrosis

    Incorrect diagnosis is the most common problem we see with avascular necrosis of the femur head. It is often mistaken for groin muscle pain, hip osteoarthritis, or even referred pain from the lower back. Early diagnosis is crucial to slow down the deterioration of the hip joint and ensure that all structures are preserved.

    AVN is a degenerative condition, so as the bone gets less blood supply, the structure weakens and collapses. Eventually, the socket part of the joint is also affected as the mechanics of the hip joint start to deteriorate. This guarantees arthritis of the hip if left for too long. The longer your hip is left untreated, the more your body starts to compensate and increase stress on other structures. These compensations result in muscle spasm and pain in other joints as well as stiffness and muscle weakness. By the time patients get to us, they have so many painful areas that it’s a challenge to find where the pain actually started.

    Another problem we see is that patients start to rely heavily on pain medication to get through the day. Pain medications as well as anti-inflammatory drugs may give short-term relief, but in the long run, it makes things a lot worse. Chronic medication use masks some of the underlying stresses placed on the hip and, even worse, some medications will actually exacerbate the condition of your hip. Make sure what you’re dealing with before you dose yourself up.

    The important role of physiotherapy treatment in avascular necrosis of the femoral head

    We love being experts in physical medicine. Our special skill lies in diagnosing uncommon or serious conditions as well as the normal day to day aches and pains. Avascular necrosis is often missed and our role is to ensure this does not happen so you can get the correct treatment early on. By doing a thorough subjective and objective evaluation, sending you for the correct investigations at the correct time and by joining all the dots we’ll make sure that you get your correct diagnosis.

    Once you have an accurate diagnosis, the planning of your treatment protocol becomes so much easier. Together with your physiotherapist you are now well on the way to returning to a more normal way of living.

    What is the physiotherapy treatment for my condition?

    Physiotherapists are in a unique position to help you with both pain control and improve function. We have extensive knowledge and experience in anatomy, physiology, and biomechanics to understand the pathology involved and the implications it has for movement and function.

    By developing a structured and progressive plan, we work to decrease your pain and give you the confidence what state your hip is actually in. Trusting your body in your daily activities is essential and comes through a process of gradually loading the joint. Progressive exercises are important to improve muscle strength, joint range of movement, and neuro-muscular control.

    The only constant thing in life, they say, is change. As such, your rehabilitation program has to change and adapt as your condition changes. Your physiotherapist is the person to slow things down in a flare-up but is also there to push you that little bit further in the good times. For AVN, treatment is a team effort and one program definitely doesn’t fit all. You need to put in the work with your physio to achieve the best results.

    During the course of treatment, your physiotherapist works to take the load off painful structures, build muscle control, and address any compensations. Exercises and modalities like laser, dry needling, myofascial release or soft tissue mobilization are also used to help you get relief and manage your pain. It is vital that you let your physio guide you on the road to recovery and monitor changes in your deep hip pain over time.

    But what if I have to go for hip surgery?

    If you ask any physiotherapist, one of our major goals is to postpone surgery for as long as possible. However, there is a place for surgical management with avascular necrosis, so if you do end up having hip surgery, your recovery will be faster if you go into the surgery in the best possible shape and you’ve already put in the work beforehand. Completing your rehabilitation program after an operation is essential to prevent complications and get you back on your feet.

    Phases of rehabilitation

    Throughout physiotherapy and rehabilitation, treatment includes taping, electrotherapy, and soft tissue mobilization or dry needling to help control the symptoms. Advice on lifestyle changes, home treatments and exercises are also an important part of physiotherapy treatment. Always changing and adapting as your condition improves.

    Acute Phase: Week 0 – 2

    In the acute phase of avascular necrosis of the femoral head, your main complaint is pain. Our goals during this stage of treatment focuses mainly on decreasing the intensity of your pain. We also need to maintain the mobility of your hip joint, within limits of your pain. Pain education and counseling during this part of your treatment protocol is an important tool for pain management. We will teach you new habits and also guide you on old habits you need to change or avoid.

    At the end of this stage you should be able to put some weight on your foot while using crutches and get up from a high chair.

    Minimal to partial weight-bearing phase: Weeks 2 – 4

    Techniques for pain management will continue during this phase, but the focus start to shift to improving mobility. Range of movement exercises is added within limits of pain. At this point, we must still avoid exercises where your full bodyweight is on your leg. Isometric exercises and very light resistance exercises for pain relief and we start with muscle activation around your hip joint. Other exercises to improve core stability and strength of your opposite hip.

    By the end of this phase of treatment, you should be able to take 50% of your bodyweight on the affected leg and get up from a dining room chair with minimal pain.

    Partial weight-bearing to full weight-bearing phase: Weeks 4-6

    By now you are still using crutches, but putting about 50% of your weight on the painful hip. You should be approaching full range of movement (compared to the other side) and pain, if any, should be intermittent and manageable. During this stage we start with standing exercises including weight shifts in different directions. The sets and repetitions of your exercises increases to start building muscle strength and endurance.

    By the end of this third phase of treatment you should be able to put your full weight on your affected hip. Turning in bed, getting out of the car and walking should be virtually pain free, but you will still have discomfort at times.

    Full weight-bearing phase: Week 6-8+

    By now you should be putting 100% of your weight on your affected hip, even though you’re still using crutches. You’ll be tempted to get rid of the crutches, but it’s important to be patient for the last week of supported walking. Your balance, muscle strength and, most importantly, hip stability won’t be back to 100% and your hip still needs some support. Exercises include functional exercises like sit to stand, squats and weight shift in all directions. In this phase of treatment we are adding more resistance using weights and resistance bands. With more repetitions and sets, your exercise sessions should feel like a workout.

    At the end of this phase you start walking without the crutches and have minimal pain with daily activities.

    Conditioning and maintenance phase: Week 8 and onwards

    The end is almost in sight! You should be walking without crutches by now and have an almost normal walking pattern. When you change direction or step off the sidewalk you shouldn’t need to grab someone next to you or hope that you won’t end up on the ground. Getting up from a chair, out of your car and walking around a shopping center should feel like normal activities and not the torturous challenge it was 8 weeks ago. This phase will include stepping exercises in different directions, weighted functional activities like squats and more complex balance exercises like standing on one leg and catching a ball outside your base of support.

    After completing this phase of treatment, you will continue your rehabilitation program with less supervision. Your physiotherapist still need to see you, but with intervals of 4 to 6 weeks in between sessions. Even though you’ll be feeling almost back to normal by now, your hip is still healing and bone strength isn’t back to 100%. The goal of your follow-up sessions are mainly to monitor the progress of your hip and limit setbacks or flare-ups.

    Healing time

    With avascular necrosis, healing time varies greatly from person to person, all depending on how much damage has occurred, the blood supply to the bone as well as how well you are doing with your exercises and lifestyle changes. The recovery time period varies from a couple of weeks of treatment to a couple of months, with some follow-up maintenance treatments thereafter.

    In the acute stage, treatment is twice a week for pain relief and to control inflammation. As the pain levels decrease, your daily function and mobility improve, sessions decreases to once a week to improve strength and range of movement. At this point, we must start working on muscle control and balance. This second stage of treatment takes 4 to 6 weeks. Once you are fully off the crutches and returning to normal activity, the sessions are spaced out to once every second to third week as we keep on working on strength, endurance, and core control, and bring in more uncontrolled and difficult positions.

    Avascular necrosis of the femoral head is a long-term condition and needs to be monitored closely. In between physiotherapy sessions, it is important to continue with your home exercises and lifestyle adaptions. It is also a good idea to follow up with your physiotherapist every 3 or 4 months during this stage so that the exercises can be modified as your requirements change. Treating AVN is a team effort and how fast and well you recover depends greatly on how much work you put into your rehabilitation.

    Other medical treatments for AVN of the hip:

    • General practitioner (GP) – medication for pain management. Even though medication won’t solve the problem, it is a useful tool to allow a short period where we can work on the hip without flaring it up.
    • Biokineticist – conditioning training and further strengthening once you have regained full range of movement and have no pain.
    • Chiropractic – manipulation of the hip joint when there is already weakness of the bone can cause further damage.
    • Walking aids – crutches is useful to deload your hip, especially in the acute phase of avascular necrosis.
    • Orthotist – orthotics or inner soles for your shoes, if indicated. This is especially useful if you have developed a leg length difference due to damage to the femoral head.

    Is there a time for surgery with avascular necrosis of the femoral head?

    Unfortunately, the insufficient blood supply and bone deterioration of AVN are usually progressive in nature. The main indicators for surgery are pain levels that remain exceedingly high (9-10 out of 10), and little to no pain relief with medication and conservative management. By that time, you won’t be able to get a good night’s sleep due to pain, while walking and changing positions during the day is excruciating.

    There are various surgical options for avascular necrosis of the femoral head, but these are the most common:

    • Core decompression and bone grafting

    The surgeon uses a drill to remove injured or diseased tissue from the area that is necrotic. This relieves some pressure in the bone and blood vessels, and hopefully, an increase in blood supply. Bone cells are then harvested from a healthy bone region and placed in the femur head. This stimulates the healing and strengthening of normal bone at the surgical site.

    • Bone marrow aspiration and stem cell procedure

    A newer procedure that may be an option in the early stages of avascular necrosis. Bone marrow is removed from the necrotic tissue and is replaced with stem cells to stimulate healthy bone formation.

    • Hip replacement surgery

    This is the final destination of late-stage and untreated avascular necrosis. If left untreated up to 90% of cases with late-stage AVN need total hip replacement surgery.

    Avascular necrosis of the femoral head is also known as:

    • Aseptic necrosis
    • Osteonecrosis of the hip
    • AVN of the femoral head
    • Avascular necrosis of the femur
    • Femoral necrosis