Knee replacement is also known as knee arthroplasty or total knee replacement. The surgical procedure is used to resurface a knee damaged by arthritis. To cap the ends of the bones that form the knee joint metal and plastic components are used, along with the kneecap. A person who has severe arthritis or a severe knee injury is considered to be the right candidate for this type of procedure.
Many different types of arthritis affect the knee joint. Osteoarthritis is a degenerative joint disease that affects mostly middle-aged and older adults causing the breakdown of joint cartilage and adjacent bone in the knees.
Rheumatoid arthritis causes inflammation of the synovial membrane and results in excessive synovial fluid, which leads to pain, and stiffness.
Traumatic arthritis is caused due by, an injury that may cause damage to the cartilage of the knee.
The main aim and focus of knee replacement surgery are resurfacing the parts of the knee joint damaged and to relieve knee pain that cannot be controlled by other treatments and medications.
Joints are part of the body where 2 or more bones meet to allow movement as most joints are mobile. Basically, the knee is comprised of 2 long leg bones that are held together by muscles, ligaments, and tendons, and each bone end is covered with a layer of cartilage to absorbs shock and protect the knee.
The quadriceps muscles (located on the front of the thighs), which straighten the legs, and the hamstring muscles (located on the back of the thighs), which bend the leg at the knee are the two groups of muscle in the knee.
Tough cords of connective tissue that connect muscles to bones are known as Tendons.
The connection between bone to bone is due to ligaments, an elastic band of tissues. The job of some ligaments of the knee is to provide stability and protection of the joints, while other ligaments limit forward and backward movement of the tibia (shin bone).
The knee consists of the following:
- Tibia. The shin bone or larger bone of the lower leg is known as Tibia.
- Femur. is the thighbone or upper leg bone.
- Patella. The kneecap is called Patella.
- Cartilage. is a type of tissue that covers the surface of a bone at a joint. Cartilage is helpful in reducing the friction of movement within a joint.
- Synovial membrane. It is a tissue that lines the joint and seals it into a joint capsule. Synovial fluid (a clear, sticky fluid) is secreted by the synovial membrane around the joint to lubricate it.
- Ligament. Is a type of tough, elastic connective tissue that surrounds the joint to give support and limits the joint’s movement.
- Tendon. Is a tough connective tissue that connects muscles to bones and helps to control the movement of the joint.
- Meniscus. Is a curved part of cartilage in the knees and other joints that plays the role of a shock absorber, increases the contact area, and deepens the knee joint.
Reasons for the procedure
The most common reason for knee replacement surgery is a treatment for pain and disability in the knee. Osteoarthritis is one of the most prevalent reasons for knee replacement surgery.
In osteoarthritis, there is a breakdown of joint cartilage. The breakdown may damage the cartilage and bones, which limits movement and may cause pain. People with such conditions may be unable to perform day to day normal activities that involve bending at the knee, such as walking or climbing stairs as they are painful. There may be swelling in the knee or the knee may “give-way” because of the unstable joint.
Other forms of arthritis, such as rheumatoid arthritis and arthritis that results from a knee injury, are also the common cause of degeneration of the knee joint. In addition, fractures, torn cartilage, and/or torn ligaments may lead to irreversible damage to the knee joint.
If other nonsurgical or medical treatments are not satisfactory, knee replacement surgery may be suggested. Some of the medical treatments for degenerative joint disease may include, the following:
- Anti-inflammatory medications
- Glucosamine and chondroitin sulfate
- Pain medications
- Limiting painful activities
- Assistive devices for walking (such as a cane)
- Physical therapy
- Cortisone injections into the knee joint
- Viscosupplementation injections (to add lubrication into the joint to make joint movement less painful)
- Weight loss (for obese persons)
Apart from these, there may be other reasons for knee replacement surgery.
Complications, as with any other surgical method can occur. Some possible complications may include, the following:
- Blood clots in the legs or lungs
- Loosening or wearing out of the prosthesis
- Continued pain or stiffness
The joint may have to be replaced again in the future if the replaced knee joint becomes loose, maybe dislodged, or may not work properly as the way it was supposed to.
The joint pain may not be relieved by surgery if the nerve or blood vessels in the area of the surgery are injured resulting in weakness or even numbness.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure
- The procedure will be explained by the concerned doctor to you and the opportunity will be given to you to ask any questions about the procedure.
- You will be asked to sign a consent form for giving your permission to do the procedure. Read the form carefully and ask questions if something is not clear.
- In addition to complete medical history, your doctor may perform a complete physical examination to ensure you are in good health before undergoing the procedure. You may undergo blood tests or other diagnostic tests.
- Notify your doctor if you are sensitive to or are allergic to any medications, latex, tape, and anesthetic agents (local and general).
- Notify your doctor of all medications (prescribed and over-the-counter) and herbal supplements that you are taking.
- Notify your doctor if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.
- If you are pregnant or suspect that you are pregnant, you should notify your doctor.
- You will be asked to fast for eight hours before the procedure, generally after midnight.
- You may receive a sedative prior to the procedure to help you relax.
- You may meet with a physical therapist prior to your surgery to discuss rehabilitation.
- Arrange for someone to help around the house for a week or two after you are discharged from the hospital.
- Based on your medical condition, your doctor may request other specific preparation.