Methods, apparatus, and systems for improving the performance of articulating prostheses. Some embodiments may comprise a first component comprising a first articulating surface and a second component comprising a second articulating surface configured for articulating with the first articulating surface. One or both of the first and second components may comprise a silicon nitride ceramic material. One or both of the first and second articulating surfaces may comprise a coating that is configured to accomplish at least one of increasing the hardness of the first articulating interface surface, reducing the coefficient of friction between the first and second articulating surfaces, decreasing the effects of wearing between the first and second articulating surfaces, and decreasing the intensity of audible noises produced by the endoprosthesis resulting from articulation between the first and second articulating surfaces during use.