The knee joint is made up of three bones joined together: the thigh bone (femur), the lower leg bone (tibia) and the kneecap (patella). These bones are connected by ligaments, tendons and muscles (Figure 1). The surfaces of the ends of these bones are covered by a smooth, shiny substance that we call articular cartilage. The articular cartilage, which acts as a padding, allows our knee joints to flex and flex, and the protection and cushioning they provide to each other. The lining of the joint capsule, which we call the synovial membrane, secretes synovial fluid, which acts as a lubricant and helps the knee joint to move freely.
The smooth surface of the articular cartilage, which is not innervated, once disrupted, exposes the subchondral bone containing the nerves. The joint loses its articular cartilage cushioning effect and the rough subchondral bone rubs against each other, causing pain and swelling when moving. The damaged knee joint may also feel swollen and painful at rest. When there is severe articular cartilage destruction, the underlying supporting bone is also destroyed and the knee joint develops an inversion or valgus deformity (Figure 1).
The causes of articular cartilage destruction are.
1, aging, wear and tear (osteoarthritis);
2, inflammatory or thickened synovial membrane erosive damage (rheumatoid arthritis, ankylosing spondylitis);
3, loss of blood supply (osteonecrosis);
4, traumatic causes, etc.
The pain caused by a lesion or injury to the knee joint makes a person feel discouraged about life, and you do not have to remain with knee pain for the rest of your life. Today total knee replacement is a routine clinical procedure that is safe and effective, and for many patients, having the surgery means being able to restore a pain-free, mobile knee and improve their quality of life. After surgery you will be able to comfortably perform daily tasks and low-impact activities. The hospital stay for knee replacement is about 2 weeks. Generally speaking, 95% of artificial joints should last 10-15 years or more.
Indications for total knee replacement
1. The main indication is the relief of pain or dysfunction caused by severe arthritis, whether or not combined with significant deformity. It is usually indicated for older, less active patients.
2, rheumatoid arthritis, ankylosing spondylitis polyarticular involvement, resulting in pain, deformity, dysfunction, no strict age limit. Especially when the progress of deformity has affected the expected effect of the proposed artificial joint replacement, deformity can be used as the main indication for artificial joint replacement;
3.After bone tumor resection.
Absolute contraindications and relative contraindications
Absolute contraindications.
1. Recent or ongoing septic infection of the knee joint;
2. Breakage or severe loss of function of the knee extension device;
3. Reverse flexion deformity secondary to muscle weakness and painlessness;
4. A well-functioning fused knee.
Relative contraindications.
1. Disorders that do not tolerate anesthesia, do not meet the metabolic needs of surgery and wound healing, or whose rehabilitation does not achieve postoperative efficacy.
Surgical complications
Like any surgery, knee replacement has possible risks and complications including.
1. various reactions to anesthetic drugs;
2. Blood clots;
3. Damage to adjacent bone, blood vessels, and nerves;
4. Patellar dislocation;
5, infection;
6, distant loosening of the prosthesis, etc.