This is a review of normal adaptive bone remodeling in response to hip and knee endoprostheses as manifested by changes in regional bone mineral density and radiophosphate uptake as a function of time. The normal evolution of change may vary with the design and composition of the implant. Appreciation of the normal temporal alterations enhances the ability to disclose prosthetic complications, but it is not without its limitations. The literature reports on the efficacy of radiophosphate to detect implant loosening are variable and differ between those that are cemented and not.