Total Knee Replacement

What is Total Knee Replacement?

Total knee replacement, also called total knee arthroplasty, is a surgical procedure in which the knee joint’s worn out or damaged surfaces are removed and replaced with a prosthesis.

Knee Arthritis

The knee is made up of the femur (thighbone), tibia (shinbone), and patella (kneecap). The two menisci, the soft cartilage between the femur and tibia, serve as a cushion and help absorb shock during motion. Arthritis (inflammation of the joints), injury, or other joint diseases can damage this protective layer, causing extreme pain and difficulty performing daily activities. In an arthritic knee, the cartilage itself becomes thinner or completely absent. In addition, the bones become thicker around the edges of the joint and may form bony “spurs.” These factors can cause pain and restrict the range of motion in the joint.

Indications for Total Knee Replacement

Total knee replacement surgery is commonly indicated for severe osteoarthritis of the knee. Osteoarthritis is a type of arthritis. It is the most common form of knee arthritis in which the joint cartilage gradually wears away, often affecting older adults. Your doctor may advise total knee replacement if you have the following:

• Severe knee pain that limits your daily activities (such as walking, getting up from a chair, or climbing stairs)
• Moderate-to-severe pain that occurs during rest or awakens you at night
• Chronic knee inflammation and swelling that is not relieved with rest or medications
• Failure to obtain pain relief from medications, injections, physical therapy, or other conservative treatments
• A bow-legged knee deformity

Total Knee Replacement Procedure

The goal of total knee replacement surgery is to relieve pain and restore the alignment and function of your knee.

• The surgery is performed under spinal or general anesthesia. Your surgeon will make an incision in the skin over the affected knee to expose the knee joint. Then, the damaged portions of the femur bone are cut at appropriate angles using specialized jigs. The femoral component is attached to the end of the femur with or without bone cement.
• Your surgeon then cuts or shaves the damaged area of the tibia (shinbone) and the cartilage. This removes the deformed part of the bone and any bony growths and creates a smooth surface to which the implants can be attached. Next, the tibial component is secured to the end of the bone with bone cement or screws.
• Your surgeon will place a plastic piece called an articular surface between the implants to provide a smooth, gliding surface for movement. This plastic insert will support the body’s weight and allow the femur to move over the tibia like the original meniscus cartilage.
• The femur and the tibia with the new components are assembled to form the new knee joint.
• To make sure the patella (kneecap) glides smoothly over the new artificial knee, its rear surface is also prepared to receive a plastic component.
• With all the new components, the knee joint is tested through its range of motion. The entire joint is then irrigated and cleaned with a sterile solution. The incision is carefully closed, drains are inserted, and a sterile dressing is placed over the incision.

Postoperative Care Following Total Knee Replacement

Rehabilitation begins immediately following the surgery. A physical therapist will teach you specific exercises to strengthen your leg and restore knee movement. Knee immobilizers are used to stabilize the knee. You will be able to walk with crutches or a walker. A continuous passive motion (CPM) machine can move the knee joint. Continuous passive motion is a device attached to the treated leg that constantly moves the joint through a controlled range of motion while you are at rest. Your physical therapist will also provide a home exercise program to strengthen your thigh and calf muscles.

Risks and Complications of Total Knee Replacement

As with any major surgery, the possible risks and complications associated with total knee replacement surgery include:

• Knee stiffness
• Infection
• Blood clots (deep vein thrombosis)
• Nerve and blood vessel damage
• Ligament injuries
• Patella (kneecap) dislocation
• Plastic liner wearing out
• Loosening of the implant