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.
Joint replacement involves surgery to replace the ends of bones in a damaged joint. This surgery creates new joint surfaces. In knee replacement surgery, the ends of the damaged thigh and lower leg (shin) bones and usually the kneecap are capped with artificial surfaces lined with metal and plastic.