Whenever you use the hip, a cushion of cartilage helps prevent friction as the hip bone moves within its socket. This ball-and-socket joint — the body’s largest — fits together in a way that allows for fluid movement and is designed to withstand repeated motion.
Despite its durability, the hip joint isn’t indestructible. With age and use, the cartilage may wear down or become damaged causing the muscles and tendons to get overused. During a fall or other injury, the hip bone itself can be fractured. Any of these conditions can lead to hip pain and should be treated by a doctor.