What is traumatic arthritis?
The culprit here is a serious hip injury or fracture that can lead to a condition called avascular necrosis. In avascular necrosis, the blood supply to the ball portion (the femoral head) of the thighbone is cut off and the bone begins to wither. As a result, the surrounding cartilage begins to deteriorate, producing pain and other symptoms. 
What it causes pain? - lack of blood supply causes the ball portion (the femoral head) of the thighbone to wither and surrounding cartilage deteriorates and bones grind or rub together.
-Ppeople who have experienced a hip injury or fracture. 

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