Avascular necrosis of the hip

Had my follow-up appointment with my orthopedic surgeon at BMC today. He reviewed the MRI I had done two weeks ago and didn’t have good news. He is pretty sure I have avascular necrosis. For those that don’t know what this is…

The hip joint is one of the true ball-and-socket joints of the body. The hip socket is called the acetabulum and forms a deep cup that surrounds the ball of the upper thigh bone. The thigh bone itself is called the femur, and the ball on the end is the femoral head. Thick muscles of the buttock at the back and the thick muscles of the thigh in the front surround the hip.

The surface of the femoral head and the inside of the acetabulum are covered with articular cartilage. This material is about one-quarter of an inch thick in most large joints. Articular cartilage is a tough, slick material that allows the surfaces to slide against one another without damage.

All of the blood supply comes into the ball that forms the hip joint through the neck of the femur (the femoral neck), a thinner area of bone that connects the ball to the shaft. If this blood supply is damaged, there is no backup. Damage to the blood supply can cause death of the bone that makes up the ball portion of the femur. Once this occurs, the bone is no longer able to maintain itself.

Living bone is always changing. To maintain a bone’s strength, bone cells are constantly repairing the wear and tear that affects the bone tissue. If this process stops the bone can begin to weaken, just like rust can affect the metal structure of a bridge. Eventually, just like a rusty bridge, the bone structure begins to collapse.

When AVN occurs in the hip joint, the top of the femoral head (the ball portion) collapses and begins to flatten. This occurs because this is where most of the weight is concentrated. The flattening creates a situation where the ball no longer fits perfectly inside the socket. Like two pieces of a mismatched piece of machinery, the joint begins to wear itself out. This leads to osteoarthritis of the hip joint, and pain.

My doctor recommended a new treatment called free fibula vascularized grafting. Basically, surgeons would remove the blood vessel and a section of my fibula (lower leg) and attach it to an existing blood vessel in the hip with the AVN. This would resupply blood to the bone, and the grafted bone would provide structural support.

It’s an 8-hour surgery, and my surgeon (who is one of the best) only recommended two places to get it done: NYC and Duke University. I already set up a consultation in NYC for November 5th and have put the calls in to see if Tricare will cover the costs. If not, I’ll try Duke.