Knee Problems - Total Knee
Replacement
Anterior
Cruciate Ligament
Posterior Cruciate Ligament
ACL
/ PCL Revision Operations
Meniscus Repair
Meniscus Transplant
Total Knee Replacement
Osteotomy
Cartilage Regeneration and Arthritis
Orthopaedic Updates
Total Knee Replacement
Each year in the United
States, over 400,000 patients undergo a total knee replacement for
osteoarthritis. The average age of these patients is 67 years and
the majority have suffered years of pain, loss of mobility, and
decreased function in the knee joint. The surgeons at Cincinnati
SportsMedicine and Orthopaedic Center have over two decades of
experience with this procedure and are trained in the latest
advances in computer-assisted total knee replacement. The Center
carefully tracks all patients to determine success rates and
complications. Published reports of this operation indicate that
many are functional 15 years postoperatively. Total knee replacement
can provide dramatic relief of pain and increased knee motion,
allowing the return to an active lifestyle, for many individuals
within just a few months after the operation.
“Patients can be assured when seeking a physician experienced in
total knee replacement techniques that our surgeons are among the
premier in this region of the country. Whether a standard procedure
or computer-assisted technique is indicated, their knowledge of
placement and ligament-balancing issues is paramount in achieving a
successful outcome. In addition, our Center’s philosophy in the
critical value of immediate postoperative rehabilitation promotes
the return of functional knee mobility and activities of daily
living, while keeping complications to an absolute minimum.”
Sue Barber-Westin, B.S.
Director of Clinical Research Studies
Cincinnati SportsMedicine Research and Education Foundation
“Computer-assisted surgery helps the physician in complex cases
obtain important information at the time of the operation to achieve
precise placement of the prosthesis. Instead of using standard
instruments to measure where points of reference are, the computer
tells us exactly where they are, within 1 or 2 degrees. This device,
like all medical advances, is used in concert with technique and
decades of experience to produce successful patient outcomes.”
Frank R. Noyes, M.D.
President and Medical Director
Cincinnati SportsMedicine Research and Education Foundation
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Questions and Answers
What is computer-assisted knee replacement?
A computer with specialized software is used in the operating room
to assist the surgeon to achieve proper placement and alignment of
the knee prosthesis. The system provides instant information on the
boney alignment of the knee joint, the function and tensions of the
ligaments required for knee stability, and the special cuts that
must be made in the femoral and tibial bones to achieve a precise
placement of the prosthesis.
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Questions
Why was computer-assisted surgery
developed?
The long-term results of knee replacement operations
before computer-assisted techniques were developed have been very
good. In fact, total knee replacement is one of the most successful
operations performed in the human body. In many published studies,
over 90% of the knee replacements were reported to be intact and
functioning 15 years after surgery. However, not all knee
replacement procedures are successful because the exact alignment
desired at surgery is not obtained. There are many reasons that
cause this problem and even the most experienced joint replacement
surgeons may encounter this complication.
Total knee replacements require exact alignment and balancing so
that weight bearing forces are spread evenly across the knee joint.
An analogy would be correctly aligning or balancing a tire on a car
so that that there is even wear over an extended period of time, and
not excessive wear on just one side. The same is true of a knee
replacement. The plastic insert is sensitive to abnormal pressures
which could result in premature wear and possible failure of the
replacement.
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Questions
How is computer-assisted knee replacement
performed?
At the beginning of the knee replacement procedure, a small tracking
device consisting of a metal rod and 3 small spheres is fixed with a
pin to the femur. A second tracking device is fixed to the tibia.
The pins which hold the tracking devices in place are inserted
through a small drill hole which does not affect the procedure.
The tracking devices contain spheres which send signals to a camera
placed 6 feet away from the operating table. The spheres broadcast
the position of the femur and tibia throughout the procedure. A
registration device is then used to ‘paint’ the outline of the tibia
and femur at special points along the boney surface which defines
the precise anatomy of these bones. When this step is completed, the
patient’s knee joint is “known” by the computer software.
A third computer tracking device is now introduced into the
procedure. This device consists of special instruments that will
provide information on the bone cuts which need to be made to
implant the tibial and femoral components of the knee replacement.
The instruments have a tracking device of 3 spheres that broadcast
to the camera and computer the position of the instruments on the
bone. The computer provides information to the surgeon before the
actual removal of bone is begun on the exact alignment and
positioning of the implant. With knowledge of the 3-dimensional
position of the knee joint, the surgeon may select the best position
to achieve excellent alignment and provide knee stability by
tensioning the ligaments appropriately.
The surgeon must undergo special training to use the
computer-assisted surgery system, much like a pilot learning to fly
in a computer-simulated plane module. As well, the surgical
assistants require special training to learn how the computerized
instruments are used during surgery.
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Questions
Is computer-assisted knee replacement
mandatory?
Although there are numerous advantages to using the
computer-assisted device for a knee replacement procedure, it is not
required or mandatory for every patient. The computer is like the
autopilot function on an airplane. In special situations, where
there are questions of visibility or positioning, the computer
provides important data to the pilot, and this is exactly the same
for the surgeon in regard to the computer-assisted replacement
procedure. In other instances with clear visibility and
straightforward situations, the pilot does not need the computer
control of the aircraft, which is like a surgeon who is performing a
straightforward knee replacement. The computer-assisted software
does allow the surgeon to perform a virtual knee replacement on the
computer screen without having an actual patient in the operating
room. The computer can simulate different situations which the
surgeon must recognize and correct. However, the computer is only as
good as the information given to it in the initial calibration of
the device. Therefore, like everything else it is not without the
possibility of giving erroneous information.
Modern knee replacement is technically difficult and the surgeon
must go through over 100 sequential steps to obtain the precise
implantation. If there is a mistake at any point in the process, it
may affect the final implantation and overall result. Experienced
surgeons know this operative sequence by heart and understand the
problem-solving steps required to obtain a successful knee
replacement within the bounds of human decision making.
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Questions
What is meant by ligament balancing during
knee replacement?
Modern knee replacement is actually two surgical procedures in one:
the balancing and tensioning of the ligaments and the fixation of
the knee replacement. The first goal is to obtain balancing and
tensioning of ligaments in the knee joint. The ligaments provide
stability and if they do not function properly there can be
instability after surgery.
In most patients, the ligaments have been stretched out or shortened
by the knee’s disease process. In a small percentage of cases, the
knee ligaments do not function properly and additional surgery may
be required to tighten or lengthen these ligaments. Patients should
realize that the surgeon cannot always predict how the ligaments are
finally going to work, along with the muscles, to provide eventual
stability of the knee joint during walking activities. With modern
knee surgery this is much less of a problem, but ligament balancing
may still be an issue, particularly in knees that had a marked
amount of a bow-leg or knock-kneed deformity before surgery.
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Questions
What are the downsides of computer-assisted
surgery?
There is additional time, usually 15 minutes, that is added to the
operative procedure. This is necessary to input the information and
recheck that the computer is collecting the correct information it
requires. It is possible that the surgeon will determine that the
computer is not providing the appropriate data and convert to visual
alignment methods. In this case, other instruments are used in the
procedure to obtain correct alignment of the replacement. The
primary goal is that the surgeon uses whatever method deemed
necessary to obtain a successful result.
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Questions
What is minimally invasive surgery of the knee
joint?
This term is applied when the surgeon selects a method in which the
tissues about the knee joint are disturbed or cut in the least
amount possible to perform the surgery. In years past, the use of
arthroscopic-guided surgery in the knee joint was considered
minimally invasive as it allowed the surgeon to perform a great deal
of the surgery through small incisions. Visualization through the
arthroscope decreased the need for large incisions or any incision
at all. A majority of ligament reconstructions and other knee
repairs are now performed by surgeons trained in these arthroscopic
techniques.
Knee replacements are now being performed using minimally invasive
types of techniques. The instruments used during the procedure are
smaller and the incisions are also smaller resulting in fewer
disturbances of the soft tissues. The computer-assisted surgical
technique allows in some cases the ability to use smaller incisions
as the computer provides virtual visualization or navigation during
the procedure.
Whenever the surgeon can minimize the incision or disturbance of
soft tissues, generally there will be less pain after surgery and a
more speedy recovery. Less pain medication is necessary and the
patient is out of bed sooner and more frequently. The rehabilitation
process is easier and the muscles regain their function faster. This
has been proven in all aspects of knee surgery when these lesser
invasive techniques have been applied.
What can affect the success of a total knee replacement?
To maintain the success of the knee replacement, the patient must
take care of the implant. Too much weight gain can place enormous
pressures on the implant and produce premature wear. It is now known
that younger male patients subject their knee replacement to large
pressures, just in activities of daily living, and may have a 2-4
times greater risk of having a knee revision procedure before 10
years. Knee replacements are not truly designed for recreational
athletic activities such as doubles tennis or skiing. Even though
some patients are fortunate to be able to do such activities after
knee replacement, there are opinions of many knee replacement
experts that this is “uncharted water” and not advisable.
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Questions
How can I schedule a Total Knee
Replacement? |
| If you are deemed a transplant candidate, our medical secretary will work with your insurance company to obtain pre-certification for the procedure. At present, the majority of insurance companies cover a portion or all of the costs of the transplant operation. As with all surgeries, the patient is ultimately responsible for the cost of the procedure. When insurance pre-certification has been obtained, your name will be placed on a waiting list. X-rays will be taken of both of your knees to determine the proper size of the transplant. Because it can be difficult to obtain high-quality transplants, there is usually a waiting period until we are able to secure the necessary tissue. |
After surgery, you are obligated to follow all of our postoperative instructions exactly. These include using crutches as directed and performing specific exercises to rehabilitate your knee. If you do not follow the instructions carefully, the transplant may fail. |
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Questions
If you'd like more information
regarding Total Knee Replacement,
please contact our Director of Clinical Studies, Sue Barber-Westin, at sbwestin@csmref.org.
