What Is Avascular Necrosis?
Avascular necrosis (AVN), also called osteonecrosis, is a condition in which bone death occurs
because of inadequate blood supply to it. Lack of blood flow may occur when there is a fracture in the bone or a joint dislocation that damages nearby blood vessels. The hip joint is most commonly affected, particularly at the head of the femur (thighbone). However, the knee and shoulder can also be affected by avascular necrosis.
Factors That Can Lead To Avascular Necrosis
Chronic use of high doses of steroid medications and heavy alcohol consumption are the two
main risk factors for avascular necrosis. Initially, small breaks appear in the bone that may
eventually collapse, causing pain.
Symptoms of Avascular Necrosis
The symptoms of avascular necrosis appear suddenly if it is the result of an injury. In other situations, patients may experience pain and stiffness gradually over a period of time. Typically, avascular necrosis causes pain and restricted range of motion in the affected joint. Your doctor can diagnose the condition using imaging such as X-rays, MRI scans, and bone scans that can help rule out other causes of joint pain.
Treatments for Avascular Necrosis
Treatment for avascular necrosis aims to prevent further loss of bone and depends on the extent of bone damage that has already occurred. Conservative treatment can reverse early stages of avascular necrosis, whereas surgical treatment may be required in more advanced stages.
Conservative Approaches for Avascular Necrosis
Conservative treatments for avascular necrosis may include:
- Medications: Non-steroidal anti-inflammatory drugs (NSAIDs) may be prescribed to help control your pain and swelling.
- Rest: Restriction of physical activities and the use of crutches to decrease weight-bearing on your joints may be beneficial.
- Exercises: Regular exercises that improve your range of motion are recommended.
- Electrical Stimulation: Electric currents can promote new bone growth. They can be applied directly to the area of damage or through electrodes fixed on the skin. They help to replace damaged bone.
Surgical Treatments for Avascular Necrosis
Avascular necrosis can be treated by one or multiple of the following methods:
Core Decompression: During this procedure, a portion of the inner layer of the bone is removed to relieve the pressure inside the bone. This decreases pain and allows for the growth of new blood vessels, thereby stimulating new bone growth. In the hip joint, this involves drilling through the neck of the femur to the affected area in the head of the femur. This procedure can be performed in an arthroscopic-assisted manner.
Bone Transplant: A healthy bone harvested from another part of your body or a cadaver is
grafted into the affected area.
Bone Reshaping (Osteotomy): This procedure is performed in advanced stages and involves reshaping of the bone, which is done to decrease the stress placed over the affected bone.
Joint Replacement: Joint replacement surgery is performed as a last resort when the bone has collapsed and requires artificial replacement.
Unique Advantages of Arthroscopic Core Decompression for AVN in the Hip Joint
- The procedure is arthroscopic-assisted, so it is minimally invasive.
- It allows the surgeon to arthroscopically visualize and stage the cartilage of the femoral head before performing the core decompression. Sometimes, this will reveal collapse of the femoral head, even if preoperative imaging did not demonstrate this.
- It gives the surgeon the ability to target the core decompression arthroscopically and very accurately.
- Through arthroscopic visualization, the surgeon can ensure that when the bone graft and/or orthobiologics are injected, they are not coming through the femoral head and into the joint.
- The surgeon can simultaneously assess other intra-articular pathology, such as labral tears and impingement, and address those problems at the same time.
Fluoroscopic Image of Arthroscopic-Assisted Core Decompression: