Arthritis is the most common reason that the hip joint wears out. Arthritis happens from chronic inflammation inside the joint. This inflammation wears out the protective cartilage around the bone. This weakens the area around the joint and the ligaments. As the protective cartilage is worn away, bone begins to rub on bone, which causes pain and makes it harder to move.
Some people have infections, injuries, or diseases such as rheumatoid arthritis or lupus that may speed up this wearing-out process. Other patients can be born with or develop an altered hip at an early age. This causes the normal wear and tear process to accelerate faster because the mechanics of the hip are changed.
Regardless of the cause, the end result is a painful hip with limited motion and the ability to perform daily activities.