Determining where the pain is coming from can help you tell the difference. Pain that emerges from the hip joint and thigh, including the deeper parts of the groin, is generally due to arthritis. You may experience pain when moving, and the pain may radiate down to your thighs, just above the knees.
On the other hand, if the pain is felt at the outer part of the upper thigh and is tender to the touch when pressed, it could be hip bursitis (1).