Total knee arthroplasty (TKA) or total knee replacement (TKR) is a common orthopaedic surgery that involves replacing the articular surfaces (femoral condyles and tibial plateau) of the knee joint with smooth metal and highly cross-linked polyethylene plastic. TKA aims to improve the quality of life of individuals with end-stage osteoarthritis by reducing pain and increasing function. The number of TKA surgeries has increased in developed countries, with younger patients receiving TKA.
Knee replacement surgery was first performed in 1968. Since then, improvements in surgical materials and techniques have greatly increased its effectiveness. Total knee replacements are one of the most successful procedures in all of medicine. According to the Agency for Healthcare Research and Quality, in 2017, more than 754,000 knee replacements were performed in the United States.
Is knee arthroplasty the same as knee replacement? Image result for knee arthroplasty Knee replacement, also called knee arthroplasty or total knee replacement, is a surgical procedure to resurface a knee damaged by arthritis. Metal and plastic parts are used to cap the ends of the bones that form the knee joint, along with the kneecap.
A knee replacement is major surgery, so is normally only recommended if other treatments, such as physiotherapy or steroid injections, have not reduced pain or improved mobility.
Surgery such as arthroplasty will not cure rheumatoid arthritis, nor will it stop disease activity. But if a joint is badly diseased, surgery may provide pain relief and improve function. Arthroplasty is considered when: Symptoms can no longer be controlled with medicine, joint injections, physiotherapy, and exercise.
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 are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily within the joint. 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.
A knee replacement (also called knee arthroplasty) might be more accurately termed a knee "resurfacing" because only the surface of the bones are replaced. There are four basic steps to a knee replacement procedure: 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. 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. 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. Insert a spacer. A medical-grade plastic spacer is inserted between the metal components to create a smooth gliding surface.
There are no absolute age or weight restrictions for total knee replacement surgery. Recommendations for surgery are based on a patient's pain and disability, not age. Most patients who undergo total knee replacement are age 50 to 80, but orthopaedic surgeons evaluate patients individually. Total knee replacements have been performed successfully at all ages, from the young teenager with juvenile arthritis to the elderly patient with degenerative arthritis.