29 Jan Total Knee Replacement
Total knee replacement facts
- Patients with severe destruction of the knee joint associated with progressive pain and impaired function may be candidates for total knee replacement.
- Osteoarthritis is the most common reason for knee replacement operation.
- Risks of total knee replacement surgery have been identified.
- Physical therapy is an essential part of rehabilitation after total knee replacement.
- Patients with artificial joints are recommended to take antibiotics before, during, and after any elective invasive procedures (including dental work).
A total knee replacement is a surgical procedure whereby the diseased knee joint is resurfaced with artificial material. The knee is a hinge joint which 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 damaged surface 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 high-density polyethylene 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 thigh bone. 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.
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 OA 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.
Risks of total knee replacement include blood clots in the legs that can travel to the lungs (pulmonary embolism). Pulmonary embolism can cause shortness of breath, chest pain, and even shock. Other risks include urinary tract infection, nausea and vomiting (usually related to pain medication), chronic knee pain and stiffness, bleeding into the knee joint, nerve damage, blood vessel injury, and infection of the knee which can require re-operation. Furthermore, the risks of anesthesia include potential heart, lung, kidney, and liver damage.
A total knee replacement generally requires around 60-80mins 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 may be 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 24 hours after surgery. Some degree of pain, discomfort, and stiffness can be expected during the early days of physical therapy.
Patients will start walking using a walker and crutches from the 2nd day of surgery. 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.
After Discharge Care
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 surgical dressings will be monitored regularly by our team. 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.
How Can People Prevent Knee Problems?
Some knee problems, such as those resulting from an accident, cannot be foreseen or prevented. However, people can prevent many knee problems by following these suggestions:
- Before exercising or participating in sports, warm up by walking or riding a stationary bicycle, then do stretches. Stretching the muscles in the front of the thigh (quadriceps) and back of the thigh (hamstrings) reduces tension on the tendons and relieves pressure on the knee during activity.
- Strengthen the leg muscles by doing specific exercises (for example, by walking up stairs or hills or by riding a stationary bicycle). A supervised workout with weights is another way to strengthen the leg muscles that support the knee.
- Avoid sudden changes in the intensity of exercise. Increase the force or duration of activity gradually.
- Wear shoes that fit properly and are in good condition. This will help maintain balance and leg alignment when walking or running. Flat feet or overpronated feet (feet that roll inward) can cause knee problems. People can often reduce some of these problems by wearing special shoe inserts (orthotics).
- Maintain a healthy weight to reduce stress on the knee. Obesity increases the risk of osteoarthritis of the knee.
What Types of Exercise Are Best for People With Knee Problems?
Ideally, everyone should get three types of exercise regularly:
- Range-of-motion exercises to help maintain normal joint movement and relieve stiffness.
- Strengthening exercises to help keep or increase muscle strength. Keeping muscles strong with exercises, such as walking up stairs, doing leg lifts or dips, or riding a stationary bicycle, helps support and protect the knee.
- Aerobic or endurance exercises to improve the function of the heart and circulation and to help control weight. Weight control can be important to people who have arthritis because extra weight puts pressure on many joints. Some studies show that aerobic exercise can reduce inflammation in some joints.
If you already have knee problems, your doctor or physical therapist can help with a plan of exercise that will help the knee(s) without increasing the risk of injury or further damage. As a general rule, you should choose gentle exercises such as swimming, aquatic exercise, or walking rather than jarring exercises such as jogging or high-impact aerobics.