Osteoarthritis (OA) is the most common form of arthritis in the world.1 You may have heard OA referred to as "wear and tear" arthritis. When OA begins to affect one of your joints, a series of reactions take place that actually begin to degrade your once-healthy bone and the "soft tissue" around the joint – tendons and cartilage.
Osteonecrosis is a disease that results from a loss of blood supply to the bone. Without adequate blood flow, sections of bone eventually die, weaken and collapse. Because this is most often seen at the ends of bones, your joints may be greatly affected. This is especially true of the hip joint, as osteonecrosis most commonly appears at the end of the femur.
Rheumatoid arthritis (RA) is an autoimmune disease in which the body's natural immune response wreaks havoc on the lining of the joints (called the synovial membrane), causing chronic inflammation and pain.1 The inflammation may eventually damage the joint's cartilage and bone, weaken the soft tissue around the joint (cartilage, ligaments and tendons) and prevent the joint from working properly.1