Core Decompression is used for young patients with initial
stages of osteonecrosis of the hip, before the head collapses.
The patients is usually on crutches for 6 - 24 weeks.
The results depend on the size of the osteonecrosis. In small
size damages, the core decompression has up to 80% successful
results. In advanced stages, the results can be less than
30% successful.
This is the most used operation to treat the osteonecrosis of
the hip. It is called "decompression operation" because the
operations is based on the idea that the blood pressure in the
bone tissue around the death bone focus is increased.
Opening the area of the dead bone from outside will attain three
objectives:
The surgeon hopes that a new, healthy bone tissue will grow
into the necrotic (dead) bone and rebuild it successively.
To help the replacement process, the surgeon may remove the
dead bone and replace it with healthy bone chips taken from
the patient's skeleton.
The operation is carried out under fluoroscopic (X-ray)
guidance.
The surgeon puts first a guide wire through the neck of the
femoral bone from the outside of the hip joint (trochanter)
into the area of dead bone. (There are other ways how to
access the necrotic bone area in the femoral head that are
more difficult). On this wire the surgeon then puts a drill
head that makes a canal through the femoral neck to open
the area of the necrotic bone.
After opening ( "decompressing") the necrotic bone area, the
surgeon may stop there.
Many surgeons, however, remove the
dead bone tissue and replace it with patient's own small
"fresh" bone chips. The cells in the "fresh" crushed bone
tissue are of course dead but the "fresh" bone tissue
contains hormones (bone morphogenetic protein hormones) that
entice formation of the new healthy bone tissue that
successively rebuilds the inlaid bone chips.
The patient must use protective weight bearing at least 6 weeks
or
longer if the decompression canal was larger. The results depend on the stage of the disease. In early
stages, before the femoral head collapses, there are up to
80 % successful results with healed necrosis. In later
stages of the disease, when the surface femoral head already
was damaged, there are less than 30% successful results.
