Hip repair:

There is a problem with the blood
supply to the bone in the hip and as a
result of that the bone dies. And as the
bone dies it becomes removed by cells
in the body and the hip will collapse.
There is a clinical trial using stem cells
to repair the hip. Here is how it works:
The doctor pulls out about six ounces
of bone marrow from the patients
pelvis through a small, quarter inch
incision. He then spins it down in a
centrifuge to concentrate the stem
cells and then through another tiny
incision, injects these cells back into
the patient through a small drill hole in
the dying hip.
The idea being that those cells would
make bone, they would recruit cells
that make blood vessels and can
restore the blood supply, and in doing
so, recreate live bone in the femoral
head of the hip, preventing it from
going on to collapse. At Boston
University Medical Center there has
been an ongoing clinical trial for 3
years doing this with an 85-percent
success rate. Patient are carefully
selected though, meaning those in
whom   the hip hasn't gone so far that
the entire hip has collapsed.

Arthroscopy to repair hip instead of
replacing it;