Hip and Knee Replacement Program What is Total Joint Replacement? Joint replacement may be necessary when the cartilage that protects the hip, knee or other joints wears out. This cartilage normally cushions the bone in the joint, absorbing shock and helping with movement. When the cartilage wears out and the joint becomes inflamed and painful this results in arthritis. The most common causes of this wear and tear are aging, heredity, past injuries, and increased body weight. Joint replacement surgery is performed to replace all or part of the joint with an artificial implant, and is well proven to relieve the pain of arthritis and can greatly improve functional status and quality of life. More than 1,000 total joint replacement (TJR) procedures are done annually through the Baystate Medical Center (BMC) Hip and Knee Replacement Program. Since 2004, Baystate Health facilities have been publicly reporting Joint Replacement care through the Hospital Quality Alliance (HQA). This reporting helps to ensure that every patient who comes to BH for joint replacement surgery receives all appropriate treatments to reduce sickness and death.