Avascular Necrosis of the Femoral Head

Avascular Necrosis of the Femoral Head

Article by John Miller

Avascular Necrosis of the Femoral Head

What is Avascular Necrosis of the Femoral Head?

Avascular Necrosis (or Osteonecrosis) is a condition affecting the upper part of the leg – specifically the femoral head. Mainly, the femoral head or ball of your hip joint receives less and less blood supply.  Since bone is living tissue when this blood supply reduces enough, the bone dies. Once the bone dies, the femoral head collapses, and if severe enough, the hip joint itself collapses.

avascular necrosis of the femoral head

Avascular Necrosis mainly affects those aged between 20-50 years old. In general, the healthier you are, the less risk you have of developing avascular necrosis. It usually comes about secondary to an underlying health issue or previous injury.

What Causes Avascular Necrosis of the Femoral Head?

Avascular necrosis arises either as a result of traumatic or nontraumatic means. Sustaining a dislocated hip – where your femoral head becomes dislodged from its joint, can result in a traumatic onset of avascular necrosis. Up to 20% of people who dislocate their hip, develop avascular necrosis of the femoral head.

Nontraumatic avascular necrosis can arise from an array of issues, most notably excessive alcohol use, chronic corticosteroid use and blood clots/any damage to the arteries supplying the femur.

The pathophysiology behind the association of chronic corticosteroid and alcohol use with avascular necrosis remains clouded. The overuse of the substances as mentioned above interferes with the breakdown of fatty substances. Consequently, the fatty substances build up and collect within the blood vessels, inevitably making them narrower. As expected, the closer the blood vessels are, the less blood flow can travel through them and reach the femoral head. Again, once this blood supply reduces enough, the bone begins to undergo necrosis (die).

Other known causes are the following diseases:

  • Gaucher’s Disease
  • Diabetes
  • HIV/AIDS
  • Sickle Cell Disease
  • Pancreatitis
  • Chemotherapy/radiation therapy
  • Autoimmune deficiencies/diseases
  • Hypertension
  • Vasculitis
  • Caisson Disease

What are the Symptoms of Avascular Necrosis?

Avascular necrosis requires time for its onset. It is relatively asymptomatic to begin, but as it progresses, the pain becomes more pronounced. Pain limited hip range of motion is the main symptom both passively and actively, which can refer to pain down the length of the leg. Generally, the pain will arise when you place pressure on the bone, which unfortunately includes walking around!

Avascular Necrosis can often mask itself as other conditions in the early phase given its general pain presentation within the hip. Therefore, it is paramount for your health practitioner to record a detailed history of your clinical presentation. And perform a thorough examination to identify if avascular necrosis is your actual cause of pain.

How is Avascular Necrosis Diagnosed?

Avascular Necrosis can often mask itself as other conditions. Once other causes are excluded, and avascular necrosis is looking like the culprit, the gold standard for diagnosis is the imaging of the hip. Although MRI has proven to be the most accurate in diagnosis, researchers and radiographers have proposed a classification system based on plain x-rays known as the Ficat system.

Other scans are less useful and are more specific to certain stages of the injury, such as a bone scan or CT scan. The MRI can be used as a diagnostic tool and also as a means to monitor the remodelling/healing.

Avascular Necrosis Treatment

Conservative treatment with physiotherapy has proven to be relatively ineffective for avascular necrosis. Although conventional treatment aims to decrease the weight-bearing load through the head of the femur (usually by implementing crutches), research has shown that the condition still progresses in 1-2 years. Without definitive treatment, 70% to 80% of all avascular necrosis of the femoral head cases will progress and inevitably undergo surgery.

Irrespective of specific surgery, the primary goal is always to preserve the natural femoral head as opposed to replacing it.

There have been nonoperative treatments options proposed. You implement these before the femoral head collapse. They are, however, still in the early stages of research and development. Trials for the use of various electromagnetic, acoustic stimulation or pharmaceutical modalities have varying success. One of the most well known and successful early treatments is core decompression – i.e. decrease the pressure inside the femoral head. This decompression is achieved through drilling holes into the femoral head to create channels for new blood vessels to nourish the affected areas of the hip or the drill canals fill with healthy bone from another part of the body. This technique has proven to be successful; especially in those with early stages, avascular necrosis based on preoperative and postoperative MRI studies.

As evident, there is a multitude of different approaches utilised to manage avascular necrosis. Ultimately, an orthopaedic opinion is paramount to ensure treatment is as effective as possible. The decision as to which treatment to select will depend on the stage the avascular necrosis in combination with the clinical evaluation of the patient.

Please seek the advice of your hip physiotherapist or doctor for specific information.

Hip Pain Treatment

A thorough analysis of WHY you are suffering hip pain from a movement, posture, or a control aspect, is vital to solving your hip pain.

Only an accurate diagnosis of the source of your hip pain can solve the pain, quickly improve your day to day function, prevent a future recurrence,  or improve your athletic performance.

The first choice of short-term therapy has been symptomatic hip treatment. This approach could include local chemical modalities such as cortisone injections or painkillers. Ice or heat could also assist along with some gentle stretching or exercise.

However, persisting hip problems will require additional investigations to assess your joint integrity or range of motion, muscle length, strength, endurance, power, contraction timing and dynamic stability control.

You should consult a healthcare practitioner who has a particular interest in hip pain and injury management to thoroughly assess your hip, groin, pelvis, lower limb and spine. Due to the kinetic chain, they all impact, especially at the high athletic performance end. A quality practitioner will educate you on your condition and combine it with exercise and manual therapy as per the Clinical Practice Guidelines. (Cibulka et al., 2017) Hip pain education should also include teaching you specific activity modification, individualised exercises, weight-loss advice (if required), and methods to unload any arthritic joints.

Recent research evidence-backed approaches have modernised physiotherapy treatment approaches to effectively managing hip pain. Together with a thorough hip assessment, your hip treatment can progress quickly to restore you to a pain-free hip and perform your regular sport or daily activities in the shortest time possible.

For specific rehabilitation advice regarding your hip pain, seek the professional advice of high quality and up-to-date physiotherapists experienced in the assessment, treatment, prevention and optimisation of hip pain and related conditions. After assessing you, they will individually prescribe therapeutic activities based on your specific needs for daily living, values, and functional activities or point you in the direction of the most suitable healthcare practitioner for you and your hip condition.

Hip Pain Treatment Options

Your hip physiotherapist may consider an extensive range of treatment options, including manual joint therapy to improve your joint mobility, muscle stretches or supportive taping. Your physiotherapist is also likely to add strengthening and hip joint control exercises as they deem appropriate for your specific functional and sporting needs. Please consult with them for advice.

Acute Injury Signs

Acute Injury Management.

Here are some warning signs that you have an injury. While some injuries are immediately evident, others can creep up slowly and progressively get worse. If you don't pay attention to both types of injuries, chronic problems can develop.

For detailed information on specific injuries, check out the injury by body part section.

Don't Ignore these Injury Warning Signs

Joint Pain

Joint pain, particularly in the knee, ankle, elbow, and wrist joints, should never be ignored. Because these joints are not covered by muscle, pain here is rarely of muscular origin. Joint pain that lasts more than 48 hours requires a professional diagnosis.

Tenderness

If you can elicit pain at a specific point in a bone, muscle, or joint, you may have a significant injury by pressing your finger into it. If the same spot on the other side of the body does not produce the same pain, you should probably see your health professional.  

Swelling

Nearly all sports or musculoskeletal injuries cause swelling. Swelling is usually quite obvious and can be seen, but occasionally you may feel as though something is swollen or "full" even though it looks normal. Swelling usually goes along with pain, redness and heat.

Reduced Range of Motion

If the swelling isn't obvious, you can usually find it by checking for a reduced range of motion in a joint. If there is significant swelling within a joint, you will lose range of motion. Compare one side of the body with the other to identify major differences. If there are any, you probably have an injury that needs attention.

Weakness

Compare sides for weakness by performing the same task. One way to tell is to lift the same weight with the right and left sides and look at the result. Or try to place body weight on one leg and then the other. A difference in your ability to support your weight is another suggestion of an injury that requires attention.

Immediate Injury Treatment: Step-by-Step Guidelines

  • Stop the activity immediately.
  • Wrap the injured part in a compression bandage.
  • Apply ice to the injured part (use a bag of crushed ice or a bag of frozen vegetables).
  • Elevate the injured part to reduce swelling.
  • Consult your health practitioner for a proper diagnosis of any serious injury.
  • Rehabilitate your injury under professional guidance.
  • Seek a second opinion if you are not improving.