Total Knee Replacement (cont.)

What is involved with the preoperative evaluation for total knee replacement?

Before surgery, the joints adjacent to the diseased knee (hip and ankle) are carefully evaluated. This is important to ensure optimal outcome from the surgery. Replacing a knee joint that is adjacent to a severely damaged joint may not yield significant improvement in function as the nearby joint may become more painful. Furthermore, all medications which the patient is taking are reviewed. Blood-thinning medications such as warfarin (Coumadin) and anti-inflammatory 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 EKG are performed to exclude significant heart and lung disease which may preclude surgery or anesthesia. Finally, a knee replacement surgery is less likely to have good long-term outcome if the patient's weight is greater than 200 pounds. Excess body weight simply puts the replaced knee at an increased risk of loosening and/or dislocation.

A similar risk is encountered in younger patients who may tend to be more active, thereby adding trauma to the replaced joint.

What happens in the postoperative period?

A total knee replacement generally requires between one and a half to three hours of operative time. After surgery, patients are taken to a recovery room, where vital organs are frequently monitored. When stabilized, patients are returned to their hospital room.

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 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 48 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. They may be removed under the guidance of the therapist for various portions of physical therapy.

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 up and down stairs and grades. A number of home exercises are given to strengthen thigh and calf muscles.

Source: MedicineNet.com
http://www.medicinenet.com/total_knee_replacement/article.htm