OVERVIEW
Avascular necrosis (AVN) or Aseptic Necrosis of the hip is caused by a disruption to the hip’s blood supply which results in the deterioration and often collapse of the ball of the thigh bone (femoral head). Early identification and treatment of the condition increases the likelihood that a patient’s hip will recover. Surgery may be required in severe cases to restore circulation to the hip or to replace the hip in end stage cases.
DESCRIPTION
Avascular necrosis of the hip is a fairly common medical condition that causes pain and discomfort in the hips of adults and children. In young children under the age of ten, avascular necrosis of the hip is referred to as “Legg-Calve-Perthes disease”.
SYMPTOMS
The most common symptoms are limping, discomfort, and/or pain in the hip, knee or pelvic area. However, proper medical diagnosis is required as these symptoms may also be caused by less severe conditions/diseases.
CAUSE
The cause of avascular necrosis of the hip is idiopathic, meaning that we do not know the reason it occurs. However, we do know that those who drink excessively, have blood clotting disorders (ex: factor V Leiden, protein C and protein S deficiency, etc), take medications such as Prednisone, or have experienced trauma to the hip and/or leg may be at increased risk.
DIAGNOSIS METHODS
The first step of diagnosis is a physical examination of the pelvis and hip. X-rays, MRI scans, ultrasounds, and in rare cases bone scans may also be required to eliminate other possible causes of pain in the hip and to assess the condition of the pelvic bones and joints.
TREATMENT
Non-surgical Treatment
Adolescents and adults with mild forms of avascular necrosis may benefit from crutches, physical therapy, and/or medication such as bisphosphanate. However, management of the disease by adjusting treatment based on x-rays and the hip’s range of motion is essential.
Surgical Treatment
While there are many options, the best course of treatment should be determined on an individual basis and take into account the stage and severity of the disease. In most cases, a multi-faceted approach to treatment is required to preserve and save the hip. Additionally, the use of an intravenous bisphosphante, such as Zoledronate, may increase the possibility of saving the femoral head.
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Core Decompression
In the early stages of adult avascular necrosis of the hip, the surgical removal of dead bone and tissue can help to stimulate the growth of new bone and revascularize the hip. To be most effective, core decompression is typically combined with other treatment methods.
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Femoral Head Reduction Surgery
A femoral head that is misshapen may require surgery if the deformity causes pain or impacts a patient’s ability to walk. The surgical procedure involves using screws and bone grafts to reshape the femoral head into a more “normal” round shape.
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Distraction of the Hip (Arthrodiastasis)
Arthrodiastasis involves separating the parts of the hip joint while keeping ligaments and tendons intact. The procedure allows the components of the hip to be properly spaced and aligned. Few surgeons perform this surgery but when prudently prescribed for the right patient and used in conjunction with other treatments it can preserve a hip that might otherwise be unsalvageable.
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Hip Replacement
Hip preservation should be the main goal of treatment, especially in patients under 40 years of age. Hip replacement should always be a last resort reserved for after all other treatments have been thoroughly considered and found to be inadequate. Hip replacement involves replacing the hip’s damaged bone and cartilage with prosthetics.
Note that I do not perform hip replacement surgeries.
CONCLUSION
Early diagnosis and vigilant management of avascular necrosis of the hip increases the possibility of a full or at least partial recovery. There are many treatment options and a surgeon should have experience with all of them to ensure that each hip and patient receives thorough treatment based on their individual condition. The longer the hip remains untreated or treated inadequately, the greater the likelihood of developing arthritis and the subsequent need for a hip replacement.
