The categorization of people by social strata occurs in all societies, ranging from the complex, state-based societies to tribal and feudal societies, which are based upon socio-economic relations among classes of nobility and classes of peasants.
Knee replacement, also known as knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and disability. It is most commonly performed for osteoarthritis,[1] and also for other knee diseases such as rheumatoid arthritis and psoriatic arthritis.
The artificial components of a total knee replacement are referred to as the prosthesis. The posterior cruciate ligament is a tissue that normally stabilizes each side of the knee joint so that the lower leg cannot slide backward in relation to the thighbone.he knee is a hinge joint which provides motion at the point where the thigh meets the lower leg. The thighbone (or femur) abuts the large bone of the lower leg (tibia) at the knee joint. During a total knee replacement, the end of the femur bone is removed and replaced with a metal shell.