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The Knee
Millions of people experience knee problems. Pain and restricted movement in the knee has many possible causes.
The knee is a joint where three bones come together: the femur (thigh bone), tibia (shin bone) and patella (kneecap). The ends of these bones are covered with articular cartilage. Between the three bones are crescent-shaped discs of connective tissue called menisci, which absorb shocks to the knee.
Muscles straighten and bend the knee, and ligaments and tendons connect bone to bone. Injuries and disorders to any of these elements can cause knee problems.
Causes of pain can include arthritis of the knee (usually caused by osteoarthritis, but can also be caused by rheumatoid and other arthritis types). Please click here for more information about how arthritis affects joints such as the knee.
Osteoarthritis, in which the cartilage in the knee wears away over time, may be caused by excessive stress on the joint from sports injuries, being overweight or deformity. Symptoms include pain, swelling and locking, or restricted movement of the knee joint – especially in the morning.
Diagnosis of arthritis of the knee will be made by your Center physician with the help of X-rays. Other tests may be necessary depending on the type of arthritis the patient has. Treatments include pain medications, anti-inflammatory drugs, weight loss and exercise to strengthen the knee. Surgical knee replacement may be prescribed in the case of serious damage.
Another common knee condition is injury to the ligaments of the knee, including the anterior and posterior cruciate ligaments and the medial and lateral collateral ligaments. Ligaments can be stretched or torn by twisting or experiencing impact to the knee, as in contact sports or automobile accidents. Pain is not always present in ligament injuries. Other symptoms include a popping sound or buckling of the knee when in use.
Diagnosis must include a thorough examination and also may include an MRI and/or arthroscopy. Depending on the severity of the injury, treatment may include strengthening exercises, a knee brace and, in the case of a complete tear, surgery followed by a rehabilitation program.
Minimally invasive Unicompartmental Knee Arthroplasty, or partial knee replacement, replaces only the diseased bone (with steel) and damaged cartilage (with plastic). Once installed, these new parts move easily against one another, reducing pain and increasing range of motion. Since only part of the joint is replaced, the incision is only 3 inches long, which reduces recovery time significantly.
One of the ways that physicians sometimes recommend treating knees is with total knee replacement surgery. The decision to have total knee replacement surgery should be made carefully after consulting your physician and learning as much as you can about the knee joint and the surgery.
In total knee replacement surgery, the bone surfaces and cartilage that have been damaged are removed and replaced with artificial surfaces made of metal and a plastic material. These artificial surfaces are called "implants" or "prostheses."
First you are taken into the operating room and given anesthesia. After the anesthesia has taken effect, the skin around the knee is thoroughly scrubbed with an antiseptic liquid. The knee is flexed about 90 degrees and the lower portion of the leg, including the foot, is placed in a special device to securely hold it in place during the surgery. Usually a tourniquet is then applied to the upper portion of the leg to help slow the flow of blood during the surgery.
An incision is made that typically extends from just above the knee to just below the knee. The incision is gradually made deeper through muscle and other tissue until the bone surfaces are exposed.
The surgeon removes the damaged bone surfaces and cartilage. Precision instruments and guides are used to help make the cuts at the correct angles so the bones will align properly after the new surfaces (implants) are attached. Removing the bone surfaces shapes the bones so that the implants will fit properly.
An implant is attached to each of the three bones. These implants are designed to help the knee joint move in a way similarly to the way the joint moved when it was healthy. The implants are attached using a special kind of cement for bones.
The implant that fits over the end of the femur is made of metal. Its surface is rounded and smooth, covering the front and back of the bone as well as the end. The implant that fits over the top of the tibia usually consists of two parts. A metal baseplate fits over the part of the bone that was cut flat. A durable plastic articular surface then is attached to the baseplate to serve as a spacer between the baseplate and the metal implant that covers the end of the femur.
If necessary, the surgeon may adjust the ligaments that surround the knee to achieve the best possible knee function. When all of the implants are in place and the ligaments are properly adjusted, the surgeon sews the layers of tissue back into their proper position. A plastic tube may be inserted into the wound to allow liquids to drain from the site during the first few hours after surgery. The edges of the skin are then sewn together, and the knee is wrapped in a sterile bandage.
Following your surgery, you will begin a gentle rehabilitation program to help strengthen the muscles around your new knee and reincorporate motion into the knee joint. On the day of surgery, you may be asked to sit on the edge of the bed, first while the therapist holds your leg and then on your own with your leg resting on a small stool or chair. Your physician or therapist also will help you stand the first few times.
A splint may be placed around your operated leg to keep it from moving and protect your knee as you stand. Once you can stand, you will probably use a walker to help you keep your balance. Initially, you will be told to place only a small amount of weight on your operated leg as you walk. As your knee becomes stronger, your physician will tell you when you can increase the amount of weight placed on your operated leg, as well as when you can drive.
Your hospital stay will usually be about two to four days. Upon returning to your home, you will need to continue taking prescribed regular medications and continue exercising as directed by your surgeon or physical therapist.
Once your knee and leg muscles are strong enough, your physician or physical therapist may recommend crutches instead of using a walker. Your therapist will give you guidelines on how far and how long you may walk. Walking, remaining active and practicing the required exercise are the quickest ways to full recovery.
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