Knee Replacement Surgery
The knee is the largest joint in the body and having healthy knees is required to perform most everyday activities. The knee is made up of the lower end of the thighbone (femur), the upper end of the shinbone (tibia), and the kneecap (patella). The ends of these three bones where they touch are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily. The menisci are located between the femur and tibia. These C-shaped wedges act as "shock absorbers" that cushion the joint. Large ligaments hold the femur and tibia together and provide stability. The long thigh muscles give the knee strength. All remaining surfaces of the knee are covered by a thin lining called the synovial membrane. This membrane releases a fluid that lubricates the cartilage, reducing friction to nearly zero in a healthy knee. Normally, all of these components work in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness, and reduced function.
Why you may need a Knee Replacement
The most common cause of chronic knee pain and disability is arthritis. Although there are many types of arthritis, most knee pain is caused by just three types: osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.
1. Osteoarthritis. This is an age-related "wear and tear" type of arthritis. It usually occurs in people 50 years of age and older, but may occur in younger people, too. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness.
2. Rheumatoid arthritis. This is a disease in which the synovial membrane that surrounds the joint becomes inflamed and thickened. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain, and stiffness. Rheumatoid arthritis is the most common form of a group of disorders termed "inflammatory arthritis."
3. Post-traumatic arthritis. This can follow a serious knee injury. Fractures of the bones surrounding the knee or tears of the knee ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.
Types of knee replacement surgery There are two main types of surgery, depending on the condition of the knee: 1. Total knee replacement (TKR) – both sides of your knee joint are replaced 2. Partial (half) knee replacement (PKR) – only one side of your joint is replaced in a smaller operation with a shorter hospital stay and recovery period Knee replacement procedure
1. Prepare the bone. The damaged cartilage surfaces at the ends of the femur and tibia are removed along with a small amount of underlying bone.
2. Position the metal implants. The removed cartilage and bone is replaced with metal components that recreate the surface of the joint. These metal parts may be cemented or "press-fit" into the bone.
3. Resurface the patella. The undersurface of the patella (kneecap) is cut and resurfaced with a plastic button. Some surgeons do not resurface the patella, depending upon the case.
4. Insert a spacer. A medical-grade plastic spacer is inserted between the metal components to create a smooth gliding surface.
Causes of knee replacement surgery
There are several reasons why your doctor may recommend knee replacement surgery. People who benefit from total knee replacement often have:
1. Severe knee pain or stiffness that limits your everyday activities, including walking, climbing stairs, and getting in and out of chairs. You may find it hard to walk more than a few blocks without significant pain and you may need to use a cane or walker
2. Moderate or severe knee pain while resting, either day or night
3. Chronic knee inflammation and swelling that does not improve with rest or medications
4. Knee deformity — a bowing in or out of your knee
5. Failure to substantially improve with other treatments such as anti-inflammatory medications, cortisone injections, lubricating injections, physical therapy, or other surgeries
Rehabilitation Post surgery A patient who has knee replacement surgery will be hospitalized for 1 to 3 days, depending on how well they follow and respond to rehabilitation.
There will be pain, but a day after the procedure medical staff will encourage patients to get up and try to walk about, usually with some kind of walking aid. It is important to follow the instructions for rehabilitation.
Physical therapy sessions aim to strengthen the knee. These may be painful, but they significantly reduce the risk of future complications.
Patients who do not have help at home may need to stay in the hospital for longer.