A total knee replacement is a surgical procedure during which the damaged knee joint is replaced with artificial material. During surgery, the end of the femur bone can be removed and replaced with a metal shell or tibia can be removed and replaced with a channeled plastic piece with a metal steam.
Also, the posterior cruciate ligament can be sacrificed, retained or substituted by a polyethylene post. It is performed in patients with damaged knee joint mostly by severe osteoarthritis associated with progressive pain and impaired function of the knee.
Before surgery, a doctor will give a patient instruction which medication must or must not take prior to surgery (usually blood-thinning and anti-inflammatory medications because they can affect platelet and blood clotting).
Preoperative evaluations will be done, which include a complete blood count, chest X-ray, EKG, urinalysis and physical exam and patient’s physician will decide which other tests are necessary based on their age and medical condition.
Surgery usually takes two to three hours. After the procedure, the extremely important part is physical therapy and it begins 48 hours after surgery.
During physical therapy patient will, among other exercises and devices, use a continuous passive motion (CPM) machine which attached to the operated leg constantly moves the knee through various degrees of range of motion for hours while the patient relaxes.
At the beginning, the patient will be using a walker or crutches and knee immobilizers to stabilize the knee during walking, sleeping, and physical therapy.
After coming home from the hospital, the patient must continue with an outpatient physical-therapy program along with home exercises to maintain muscle strength for the purposes of joint stability. Ideal future activity is swimming and sports which include running or contact must be avoided.
It is also important that patients with joint replacements alert their doctors and dentists that they have an artificial joint because these joints are at risk for infection by bacteria.
It is recommended that patients take antibiotics before, during, and immediately after any elective procedures in order to prevent infection of the replaced joint.
Sometimes patients require a second operation a few years later because of loosening, fracture, or other complications of the replaced joint.
The good long-term outcome also depends on the patient’s weight because excess body weight simply puts the replaced knee at an increased risk of loosening and/or dislocation.
The risks of undergoing a total knee replacement includes:
- Blood clots in the legs that can travel to the lungs (pulmonary embolism)
- Chronic knee pain and stiffness
- Urinary tract infection
- Bleeding into the knee joint
- Nerve damage
- Blood vessel injury
- Infection of the knee which can require re-operation
