My surgeon selected a size smaller ball than appropriate for my hip replacement because the right one was dropped, is this okay?

Yes.: There are a number of ball sizes available and each one differs in diameter (size) from the next one by only a few millimeters. A smaller head size means a thicker layer of polyethylene in the acetabular shell, which theoretically may mean it will last longer. In any event, it's not something to worry about.

Yes: The smaller balls (femoral head) actually cause slower wear and tear of the plastic prosthesis. The dislocation rate is slightly higher initially, but usually become the same after about 3 months.