Arthroplasty is an elective surgery to reshape or reconstruct a damaged or diseased joint. It may entail joint replacement, involving the replacement of part (partial arthroplasty) or the entire joint (total arthroplasty) with a prosthesis (an artificial body part) and the resurfacing or relining of the bones, or more minimal reconstruction of the joint.

Prostheses replace worn-away or destroyed cartilage and bone. They typically last 10 to 13 years. Some new ones have been promoted as being able to last 20 years or longer, but this has not been seen clinically yet.

More than 500,000 joint replacements are performed in the United States each year, according to the Arthritis Foundation. Pain and decreased quality of life are the two main reasons for undergoing arthroplasty.

The success of arthroplasty depends on patient selection, particularly with total arthroplasty. Because of the limited life of prosthetic devices, total arthroplasty is usually not performed in younger patients. However, waiting too long to deal with a joint problem may reduce the likelihood of a good outcome from arthroplasty years later.

Candidates for total arthroplasty are typically over the age of 60 years because physically active young people tend to wear out prostheses quickly. The joint of the candidate must have limited function that interferes with activity, such as chronic stiffness and swelling, difficulty walking (in a joint associated with the legs) or lifting/holding things (in a joint associated with the arms) and moderate to severe pain from osteoarthritis even when at rest. Deformity of the joint increases the likelihood that arthroplasty will be used in treatment.

Arthroplasty is typically not a chosen course of action until other methods (e.g., resting, weight loss, physical therapy, analgesics) have proven unsuccessful. Good candidates for this procedure are generally healthy, without infection or conditions that restrict blood flow, and preferably without diabetes or other endocrine disorders. They generally remain active and maintain a healthy body weight. Candidates for lesser forms of arthroplasty may have fewer and less serious conditions. 

The prostheses that may be used in arthroplasty are finite (limited) in duration. New designs are allowing prostheses to last longer and longer. Regardless of the design, prostheses typically last longer in the older, less active population. Youthful activity levels generally wear out a prosthesis more quickly, requiring that it be replaced more often.