Total Knee Replacement ( TKR ) surgery is a technique that removes a diseased knee joint and replaces it with a prosthesis (artificial joint). A surgeon cuts away damaged bone and cartilage from your thighbone, shinbone and kneecap, and replaces it with an artificial joint (prosthesis) made of metal alloys, high-grade plastics and polymers. Depending on the condition of the cartilage on the undersurface of the kneecap, this may also be replaced. The actual procedure takes about 1 ½ to 2 hours.
Knee replacement surgery is also known as total knee arthroplasty.

A unicondylar knee replacement replaces only half of the knee joint. This procedure is performed if the damage is limited to just one side of the joint.

A total hip replacement (THR) - also called a hip arthroplasty- is a surgical procedure that re-forms the hip joint. Hip replacement surgery involves the replacement of the femoral head — the "ball" of the thighbone with a metal ball and stem.

The most widely used implant features a metal stem and a metal cup, with a plastic spacer in between. These implants have a well documented success rate , with over 90% functioning well after 10 years and 80% after 20 years.
The actual procedure takes about 2 hours

Traditional hip replacement requires the removal of a significant quantum of bone mass - the head of the femur (the bone in the upper leg) to replace it with an artificial ball.

Hip resurfacing is a more conservative surgical procedure which shields these worn ball-and-socket surfaces in the hip joint with smooth, durable metal components. By conserving more bone mass, younger patients retain the option of a traditional hip replacement procedure, if later needed.