The present invention relates to customized implants for bone replacement that are prepared from poly(ether ketone ketone) or PEKK, and to a computer-based imaging and rapid prototyping (RP)-based manufacturing method for the design and manufacture of these customized implants. The PEKK customized implants made using rapid prototyping demonstrate biomechanical properties similar (if not identical) to that of natural bone even when prepared without the use of processing aids such as carbon black and aluminum powder.