Avascular Necrosis Of The Hip

Avascular necrosis of the hip, otherwise known as hip osteonecrosis, refers to the disruption of blood flow to the “ball” part of the hip joint (femoral head), causing the bone to collapse eventually. While osteonecrosis can affect other bones around the shoulders, knees, and ankles, it most typically occurs in the hip.


a person holding her abdomen because of pain

Most people do not exhibit any symptoms in the early stages of avascular necrosis. However, as the condition worsens, you may feel pain in your hip especially when you put weight on it. The pain can be mild, but may gradually worsen, with most of it being centred on the groin, thigh, or buttock, but it can also radiate to the knee. 


In rare cases, some patients may develop avascular necrosis on both sides of their hip. To prevent your condition from worsening, it is advisable to see a doctor or an orthopaedic specialist as soon as you feel persistent pain in any joint. In addition, getting an early diagnosis improves your chances of successful treatment, and preserving your native hip joint.



Avascular necrosis of the hip occurs when the blood supply to the femoral head is cut off. As a result of inadequate nourishment, the bone in the head of the femur dies and will gradually collapse. This increases the loading stress to the articular cartilage, resulting in cartilage damage and joint arthritis.


Risk Factors

While there is no known cause behind the disruption of blood supply, there are certain risk factors that increases the prevalence of hip osteonecrosis: 

  • Hip dislocations, fractures, and other injuries to the hip increases the risk of blood vessel damage within the area. This impairs circulation to the femoral head. 
  • Overconsumption of alcohol can result in the accumulation of fatty deposits in the blood vessels. This causes your cortisone levels to increase, ultimately reducing blood supply to the bone. 
  • Long-term use of steroids
  • Medical conditions such as autoimmune disease (e.g, systemic lupus erythematosus), blood disorders, and blood vessel inflammation (vasculitis)
  • Decompression sickness in divers



Apart from understanding your symptoms and medical history, your orthopaedic specialist will also perform a physical exam on you. They may check for pain when pressure is placed on your hip or move your hip through various positions to check for reduced range of motion. 


As there are many causes of joint pain, your doctor may also order imaging tests to determine the source of pain. X-rays can only reveal changes to the bone structure in the later stages of avascular necrosis and to identify the progression to hip arthritis. MRI can produce detailed images of early changes in your bone structure and identify bone swelling seen in early avascular necrosis.



The main treatment goal for avascular necrosis is to minimise further bone loss. In the early stages of the condition, your orthopaedic doctor will recommend nonsurgical treatment options like bisphosphonates, anti-inflammatory medications, lifestyle changes, and the use of walking aids. These treatment options help to relieve pain and may slow the progression of the disease.


However, surgical treatment is often necessary and should be performed early. Hip osteonecrosis in the very early stages before the femoral head collapses are ideal candidates for hip preservation procedures. These include core decompression to relieve pressure on the swollen bone and stimulate blood vessel ingrowth, bone grafting (structural grafts to fill the space of the dead bone or ‘live’ grafts, which bring blood supply to the area of the dead one), or osteotomy to offload the diseased bone.


However, In advanced cases, when the femoral head has collapsed or there is gross hip arthritis, it may be necessary to perform a total hip replacement. Hip replacements can greatly reduce the pain and disability arising from hip arthritis, and allow you to improve your quality of life.

Every case is different; hence it is best to consult an orthopaedic surgeon for an accurate diagnosis so that you can obtain the best treatment option that is most suitable for you. Reach out to us today if you suspect that you are suffering from hip osteonecrosis and let us help you enjoy a better quality of life. 


Here, at Advanced Orthopaedics, Dr Poh and his team specialises in the full spectrum of hip surgeries including hip preservation and hip replacement, ensuring that you get the most appropriate treatment for your condition.