Extensive degenerative disease of the hip is unusual without a predisposing cause. In this instance, there is a history of previous dislocation. The head has not collapsed and there is no evidence of avascular necrosis at this time.

Osteoarthritis is believed to be caused by trauma, either overt or as an accumulation of microtrauma over years, although there is also a hereditary form called primary osteoarthritis that occurs primarily in middle-aged women.