Total Knee Replacement Surgery – FAQs

Total knee replacement is a surgical procedure whereby the diseased knee joint is replaced with artificial material. The knee is a hinge joint which provides motion at the point where the thigh meets the lower leg. The thigh bone (or femur) abuts the large bone of the lower leg (tibia) at the knee joint. During a total knee replacement, the end of the femur bone is removed and replaced with a metal shell. The end of the lower leg bone (tibia) is also removed and replaced with a channeled plastic piece with a metal stem. Depending on the condition of the kneecap portion of the knee joint, a plastic “button” may also be added under the kneecap surface.

Cause

• Osteoarthritis usually occurs in people of 50 years of age and older and often in individuals with a family history of arthritis. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness.
• Rheumatoid arthritis is a disease in which the membrane around the joint becomes thickened and inflamed, producing too much fluid that overfills the joint space. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain, and stiffness.
• Traumatic arthritis can follow a serious knee injury. A knee fracture or severe tears of the knee ligaments may damage the cartilage over time, causing knee pain and limiting knee function.

• Severe knee pain that limits everyday activities, including walking, climbingstairs, and getting in and out of chairs.
• Moderate or severe knee pain while resting, either day or night
• Chronic knee inflammation and swelling that does not improve with rest or medications
• Knee deformity: a bowing in or out of your knee
• Knee stiffness: inability to bend and straighten your knee
• Failure to obtain pain relief inspite of using anti-inflammatory drugs. Failure to substantially improve with other treatments such as cortisone injections, physical therapy, or other surgeries

Preoperative Evaluation

• Before surgery, joints adjacent to the diseased knee are carefully evaluated. This is important to ensure optimal outcome from the surgery.
• Blood thinning medications such as Aspirin, may have to be adjusted or discontinued prior to surgery.
• Routine blood tests of liver and kidney function, and urine tests are evaluated for signs of anemia, infection or abnormal metabolism. Chest x-ray and ECG are performed to exclude significant heart and lung disease which may preclude surgery or anesthesia.

Surgery Procedure

After admission in the hospital, you will be evaluated by a member of the anesthesia team. The most common types of anesthesia are general anesthesia, in which you are asleep throughout the procedure, and spinal or epidural anesthesia, in which you are awake but your legs are anesthetized. The anesthesia team will determine which type of anesthesia will be best for you with your input.

The procedure itself takes approximately 2 hours. Your orthopedic surgeon will remove the damaged cartilage and bone and then position the new metal and plastic joint surfaces to restore the alignment and function of your knee.

After surgery, you will be moved to the recovery room, where you will remain for 1 to 2 hours while your recovery from anesthesia is monitored. After you awaken, you will be taken to ward.

A recent advance in the performance of total knee replacement is the use of minimally invasive surgical approaches which has many advantages like the incisions are approximately half the size of those used in a standard approach which results in quicker rehabilitation, less pain, and a shorter hospitalization.

Postoperative Period

After surgery, patients are taken to a recovery room and are kept under observation. When stabilized, they are shifted to ward.

Passage of urine can be difficult in the immediate postoperative period, and this condition can be aggravated by pain medications. A catheter inserted into the urethra (a foley’s catheter) allows free passage of urine until the patient becomes more mobile. Physical therapy is an extremely important part of rehabilitation and requires full participation by the patient for optimal outcome. Patients can begin physical therapy forty-eight hours after surgery. Some degree of pain, discomfort, and stiffness can be expected during the early days of physical therapy. Knee immobilizers are used in order to stabilize the knee while undergoing physical therapy, walking, and sleeping. A unique device that can help speed recovery is the continuous passive motion (CPM) machine. The CPM machine is first attached to the operated leg. The machine then constantly moves the knee through various degrees of range of motion for hours while the patient relaxes.

Patients will start walking using a walker and crutches. Eventually, patients will learn to walk and climb stairs. A number of home exercises are given to strengthen thigh and calf muscles.

Recovery

It is important for patients to continue in an outpatient physical therapy program along with home exercises for optimal outcome of total knee replacement surgery. The wound will be monitored by your surgeon for healing. Patients also should watch for warning signs of infection including abnormal redness, increasing warmth, swelling, or unusual pain. It is important to report any injury to the joint to the doctor immediately. Future activities are generally limited to those that do not risk injuring the replaced joint. Sports that involve running or contact are avoided, in favor of leisure sports, such as golf, and swimming. Swimming is the ideal form of exercise, since the sport improves muscle strength and endurance without exerting any pressure or stress on the replaced joint.

These joints are at risk for infection by bacteria introduced by any invasive procedures such as surgery, dental or gum work, urological and endoscopic procedures, as well as from infections elsewhere in the body. Patients are recommended to take antibiotics before, during, and immediately after any elective procedures in order to prevent infection of the replaced joint.

• Blood clots in the leg veins are the most common complication. Your orthopaedic surgeon will outline a prevention program, which may include periodic elevation of your legs, lower leg exercises to increase circulation, support stockings, and medication to thin your blood.
• Infection of the replaced joint can occur, though rare.
• Although implant designs and materials as well as surgical techniques have been optimized, wear of the bearing surfaces or loosening of the components may occur.
• Additionally, scarring of the knee can occasionally occur, and motion may be more limited, particularly in patients with limited motion before surgery.
• Finally, although rare, injury to the nerves or blood vessels around the knee can occur during surgery.