About Total Knee Replacement at The Stone Clinic
• Joint replacement means replacing the worn-out, painful joint surfaces of the knee with metal and plastic components
• Utilized if biologic knee replacement fails
• If only one part of the knee is worn, a partial (uni) knee replacement can be performed
• Can last up to 20 years
Artificial knee replacement means replacing the worn-out, painful joint surfaces of the knee with metal and plastic components. At The Stone Clinic, artificial joints are utilized if biologic joint replacement techniques (meniscus cartilage replacement and articular cartilage replacement) cannot effectively relieve pain and improve function. While we have been very successful at helping people delay or avoid artificial joint replacements despite relatively severe arthritis, there comes a time when artificial joint replacement is indicated.
Artificial knee joints are temporary devices that last for up to 20 years (but can fail as early as one year), provide excellent pain relief, and range of motion from 0 - 120° (though the range varies from patient to patient). We use the newest designs that, with their rotating and replaceable plateaus, permit a wide range of sports participation.
Artificial knee joints are indicated for patients with bone-on-bone, painful arthritis in multiple parts of the knee. If only one part of the knee is worn out, we use partial, or uni-compartmental, replacements and only resurface the worn out area.
The major risks of artificial joint replacements are loosening of the cement used to affix the joint, stiffness, pain, loss of motion, and a very low risk of infection or blood clot formation at the time of surgery.
The steps involved in replacing the knee begin with making an incision on the front of the knee to allow access to the knee joint. This incision has become shorter now that we use minimally-invasive surgical instruments and techniques.
Shaping the Distal Femoral Bone: Once the knee joint is entered, a special, customized knee instrumentation device is placed on the end of the femur. This device is used to make sure the bone is cut in the proper alignment to the leg's original angles, even if the arthritis has made the patient bowlegged or knock-kneed. The custom device is used to cut several pieces of bone from the distal femur so the artificial knee can replace the worn surfaces with a metal surface.
Personalized, Computer-Generated
Femoral Instrumentation Device
Preparing the Tibial Bone: Attention is turned toward the lower bone, the tibia. The top of the tibia is cut using another customized knee instrumentation device that ensures the alignment is satisfactory.
Personalized, Computer-Generated
Tibial Instrumentation Device
Preparing the Patella: If severely damaged, the undersurface of the patella is removed.
Placing the Femoral Component: The metal femoral component is placed on the femur. The metal prosthesis is cut so it matches the taper almost exactly. With a cemented, femoral component, an epoxy cement is used to attach the metal prosthesis to the bone.
Placing the Tibial Components: The metal tray that will hold the polyethylene spacer is attached to the top of the tibia, and the metal tray is cemented into place. The plastic spacer is then attached to the metal tray of the tibial component. If this component wears out while the rest of the artificial knee is sound, it can be replaced.
Placing the Patellar Component: A patella button is sometimes cemented into place behind the patella depending on the degree of arthritis.
The artificial knee replacement is now complete.
Closing the Incision: Nylon stitches or absorbable stitches are used to close the skin.
Components for Knee Replacement Surgery
Implant designs vary in important ways to meet specific patient needs. Restoration of normal knee joint function is the goal of knee replacement surgery. We select the implant based on the patient’s anatomy, degree of looseness of the knee, their range of motion, and their planned sports activities.
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