Total knee replacement has become the “gold standard” for the
treatment of debilitating pain and dysfunction of the knee brought on
by severe arthritis in the knee joint. When a patient’s arthritis
pain becomes severe and is not improved by non-surgical means then this
patient may become a candidate for total knee replacement surgery. Stated
simply, a total knee replacement surgery removes the damaged surfaces
of the bones of the thigh, shin, and knee cap with artificial surfaces
made of surgical grade stainless steel and ultra-high molecular weight
polyethylene plastic. A total knee replacement can give patients 15-20
years of pain free function to a knee that once was crippled by arthritis.
Critical to the success of a total knee replacement surgery is the accurate
placement of the new metal and plastic surfaces on the bones. Improper
placement of the total knee components can lead to decreased function
of the knee and early failure and can wear or loosen from the bone.
Phillip Graehl, M.D. a board certified orthopedic surgeon who specializes
in reconstructive and arthroscopic surgery of the hip and knee says, “Essential
to the performance of total knee replacements in my practice, is the use
of Patient Specific Instrumentation (PSI)".
PSI is used in Dr. Graehl's clinic because "it facilitates optimal
orientation of the total knee replacement components on the bones to assure
accurate restoration of the knee joint alignment and function". In
order to obtain the PSI for a total knee replacement surgery, Dr. Graehl
has his patients undergo a CT scan of the affected lower extremity. The
digital data gathered by the CT scan is then sent to the manufacturer
of the artificial knee replacement parts. They are able to produce customized
replacement parts that fit an individual bones exactly. “These customized
parts are manufactured knowing that, despite the individual variations
in a patient’s bone size or orientation, the correct placement of
the total knee replacement will be accomplished,” says Dr. Graehl.