A total knee replacement is a surgical procedure whereby the diseased knee joint is replaced with artificial material. The knee is a hinge joint that provides motion at the point where the thigh meets the lower leg. The thighbone (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. The artificial components of a total knee replacement are referred to as the prosthesis. The posterior cruciate ligament is a tissue that normally stabilizes each side of the knee joint so that the lower leg cannot slide backward in relation to the thighbone. In total knee replacement surgery, this ligament is either retained, sacrificed, or substituted by a polyethylene post. Each of these various designs of total knee replacement has its own particular benefits and risks.
What patients should consider a total knee replacement?
Total knee replacement surgery is considered for patients whose knee joints have been damaged by either progressive arthritis, trauma, or other rare destructive diseases of the joint. The most common reason for knee replacement is severe osteoarthritis of the knees. Regardless of the cause of the damage to the joint, the resulting progressively increasing pain and stiffness and decreasing daily function lead the patient to consider total knee replacement. Decisions regarding whether or when to undergo knee replacement surgery are not easy. Patients should understand the risks as well as the benefits before making these decisions about knee replacement.
What is involved with the pre-operative 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 and recovery 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 if it is abnormal. Furthermore, all medications that 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 knee replacement 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 that 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 and makes recovery more difficult. Another risk is encountered in younger patients who may tend to be more active, thereby adding trauma to the replaced joint.
How does the patient continue to improve as an outpatient after discharge from the hospital? What are recommended exercises?
For an optimal outcome after total knee replacement surgery, it is important for patients to continue in an outpatient physical-therapy program along with home exercises during the healing process. Patients will be asked to continue exercising the muscles around the replaced joint to prevent scarring (and contracture) and maintain muscle strength for the purposes of joint stability. These exercises after surgery can reduce recovery time and lead to optimal strength and stability. The wound will be monitored by the surgeon and his/her staff 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. Patients with joint replacements should alert their doctors and dentists that they have an artificial joint. These joints are at risk for infection by bacteria introduced by any invasive procedures such as surgery, dental or gum procedures, urological and endoscopic procedures, as well as from infections elsewhere in the body. The treating physician will typically prescribe antibiotics before, during, and immediately after any elective procedures in order to prevent infection of the replaced joint. Though infrequent, patients with total knee replacements can require a second operation years later. The second operation can be necessary because of loosening, fracture, or other complications of the replaced joint. Reoperations are generally not as successful as original operations and carry higher risks of complications. Future replacement devices and techniques will improve patient outcomes and lead to fewer complications.
Meet Our Doctors
Our administration and support staff all have exceptional people skills and trained to assist you with all medical enquiries.
All Days : 24 Hours