Core Decompression for Avascular Necrosis of the Hip

Avascular necrosis (AVN), also known as osteonecrosis, is a condition where bone starts to die due to lack of blood supply.  There are direct and indirect causes of AVN.  Dr. Fischer will discuss the details of your medical history to create a customized treatment plan.

Avascular necrosis commonly affects the head of the femur. Necrosis leads to tiny cracks on the bone which can ultimately cause the head of the femur to collapse.  This condition causes pain due to increased pressure in the blood vessels of the bone marrow at the region of the necrosis.

Early stages of avascular necrosis before joint collapse may be treated with core decompression which reduces pressure, promotes blood flow, and encourages healing of the bone.


Core decompression is indicated in the early stages of AVN when the surface of the head is still smooth and round.  It is performed to hopefully preserve the native hip joint.  If the joint collapses or if the decompression fails, a total hip replacement is required to alleviate pain and restore function.

Surgical Procedure

Core decompression is done under regional or general anesthesia. The patient is placed on their back in supine position. Live X-ray imaging is used to guide drill position during the procedure.

A small incision is made on the outside of the hip and a drill is passed from the incision through the neck of the femur to the necrotic area in the femoral head. Multiple tracts may be drilled to address the full extent of the lesion. This reduces the pressure and creates space for new blood vessels to grow and nourish the existing bone.

The cavity that is left behind in the bone is sometimes filled with bone graft taken either from another part of your body or the bone bank.  Sometimes synthetic bone graft material is used.

Post-Operative Care

After the operation, crutches are to be used for 6 to 12 weeks to prevent weight bearing at the hip joint until the femur bone heals completely. You will be able to resume your regular activities 3 months after the surgery.


The advantages of core decompression include the following:

  • May prevent femoral head collapse
  • Preserves femoral bone
  • May delay or avoid the need for total hip replacement

Risks and Complications

As with all surgeries, core decompression may be associated with certain complications such as:

  • Fracture along the core track
  • Perforations in the femoral head
  • Deep vein thrombosis