As we get older, years and decades of mechanical stress may lead to deterioration of joints, ligaments, and tendons. This degenerative process, commonly known as arthritis, primarily affects weight-bearing joints such as the hips and knees and those found in the lumbar spine. The shoulder, too, is especially prone to undergo arthritic changes owing to its extreme mobility. The extensive range of motion at the shoulder is built-in to the design of this structure, but the tradeoff is instability. The design of the shoulder sacrifices stability for mobility.
