The femoral neck decreased, but the total hip was the same. Her bone density is average for her age.
Some studies have shown that the total hip is more reliable than the subregions of the hip. The femoral neck is only a small part of the total hip and it can be difficult to measure the exact same small region the next year.
Look carefully at the images and you can tell there has been some rotation and change in position. The region of interest for the femoral neck has moved laterally to an area of lower density. Notice that the "Ward's" box is now within the femoral neck. The total hip, however, is approximately the same area for both scans.
This patient's pain was due to her arthritis.