Cracked Plaster

The plaster, and as far as I can tell some of the concrete under the plaster has cracked out around the handrail base. The piece that is actually missing must be about 2.5 inches on a side, triangluar shaped, about 3/4 inch deep. But there are more cracks that appear to go deeper, and farther out. Hard to tell because the bezel covers it and I can't get it up out of the way.
So what would be the best method of repairing this, and NOT have it occur again? The handrail is a single (stainless) bent pipe that has a connection in the deck and in the pool bottom.
Suggestions?
NE Houston, TX

how about posting some pictures of your problem so that we can address it properly and see what we are dealing with