Can stress fractures in the hip cause arthritis later?

Not likely: Most stress fractures of the hip do not cause long term problems with the blood supply to the hip joint and therefore will not cause damage to the cartilage. It is the loss of cartilage or damage to the cartilage that causes arthritis.

It may or may not: It depends if the fracture went into the joint. That could cause arthritis later. However even a fracture at another location if it interferes with normal locomotion could possibly cause arthritis at a later time. It is important to remember that there are a lot of other factors that influence the development of arthritis.