What is Total Knee Replacement?
Total knee replacement (TKR), also known as total knee arthroplasty (TKA), is an orthopaedic surgical operation in which artificial implants are placed in a patient’s dysfunctional knee. The artificial parts in this joint reconstruction include metal and plastic parts that are meant to mimic the function of a natural, healthy knee joint.
A healthy knee joint is comprised of bones, cartilage, and ligaments. The bones of the knee joint include the femur (thigh bone) and tibia (shin bone). The ends of these two bones meet in the knee joint, providing structure and stability so a person can walk properly. The end of the tibia (shin) is flat and the end of the femur (thigh) is round. A cartilage structure, called the meniscus, sits on the flat end of the tibia to provide cushioning between the two bones. Likewise, a cartilage structure, called articular cartilage, can be seen on the round end of the femur, which also provides cushioning between the bones.
The four ligaments in a healthy knee joint include the Anterior Cruciate Ligament (ACL), Posterior Cruciate Ligament (PCL), Medial Collateral Ligament (MCL), and Lateral Collateral Ligament (LCL). The LCL is on the outer side of the knee, the MCL is on the inner side of the knee. The ACL and PCL are in the middle, between the tibia and femur. These ligaments provide stability so the knee can function properly while a person does things like walk, run, squat, and pivot.
A total knee replacement procedure typically takes place when someone experiences chronic knee pain. This knee pain commonly arises after many years of active living. An active lifestyle may cause the cartilage in the knee to wear down, leaving the knee joint with no cushioning, which causes bone-on-bone interaction in the joint. Bone-on-bone interaction causes severe pain in the knee, especially when trying to participate in activities; even activities as simple as walking.
The important thing to remember about the components of a healthy knee (bones, cartilage, and ligaments) is that they provide structure and stability in order for a person to live an active, pain-free lifestyle. Any damage or hindrance to any of these knee structures can prevent a person from living the life they want to live.
As mentioned previously, a reconstructed knee joint includes artificial parts made of metal and plastic. The artificial tibial (shin bone) component is a metal tray that sits on the end of the tibia. The end of the tibia bone will be cut specifically so the metal tray can fit correctly on the end of the bone. The artificial femoral (thigh bone) component is a metal “cap” that is placed on the end of the femur. The end of the femur bone will also be cut specifically so the metal cap can fit correctly. The cartilage components of the knee will be replaced with a plastic piece between the two artificial metal components on the ends of the bones. The new plastic piece will provide a cushion between the metal components. The ligaments of the knee joint may be removed, depending on the type of implant the patient receives.
Someone may be a candidate for TKR if they struggle to live a pain-free life every day because of a dysfunctional knee. The candidate may find that pain is an obstacle when trying to complete activities such as walking, squatting, kneeling, and pivoting. If someone is hindered by their current knee function, they may be able to improve their quality of life after total knee replacement.Always consult a doctor when considering medical treatment, such as knee replacement, to discuss specific knee implants, treatment, and rehab.