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Arthritis by definition is the loss of articular cartilage
resulting in pain, swelling and
deformity of a specific joint. Etiologies of arthritis
include degeneration, inflammation,
post traumatic and infection. The knee contains three
separate joints, the medialjoint,
the lateral joint and the patella joint. You can develop
arthritis of one area alone or all
three. ln the 1940's orthopedists started to develop
surgical treatments for arthritis
of the knee.
The earliest surgical procedures involved placement of
various types of spacers to
replace the lost cartilage. The spacers were eventually
replaced by resurfacing
designs. Over the years these components evolved to mimic
the actual anatomy of
the femur, tibia and patella. The designs were both
constrained and nonconstrained.
Although there is still debate concerning the best fixation
methods and how many
surfaces need to be replaced, there is general agreement
that component placement,
overall axis alignment and soft tissue balancing are crucial
to a successful outcome.
The earliest alignment techniques were performed using
simple hand-eye positioning.
With time, cutting jigs were constructed that used either
extramedullary or
intramedullary means of reproducing anatomic alignment. As
the jigs have become
smaller, it is possible to perform these surgeries through
small incisions. lncision
length has been cut in half. This results in less pain,
bleeding and scar formation .
The component materials have evolved as well. The metals and
plastics are stronger
and more polished leading to less wear and longer life
spans.
The latest innovations involve the incorporation of
computers. Presently we are using
computers in the operating room to improve the accuracy of
the cuts and the
alignment. Markers are placed on the bones and the joint is
mapped out by the
computer. The problem with some of these designs is that it
can add significant
operating time and markers can leave stress risers leading
to bone fracture. Now we
are able to use plain x-rays of the extremity, an MRI of the
knee and the computer to
produce jigs that are custom made for each patient's
anatomy. This allows multiple
steps to be performed in the lab before the surgery. These
evolving techniques are
helping to improve the results of total knee replacement. |
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