Abstract: A modular acetabular bearing assembly which minimizes or eliminates the production of wear debris resulting from relative motion at the interface between the acetabular shell and bearing insert portions of the modular acetabular bearing assembly. The modular acetabular bearing assembly includes an acetabular shell and composite bearing insert. The composite bearing insert includes an endoskeleton and a polymer layer which is preferably molded into and locked within the endoskeleton. The endoskeleton is configured to be locked within the acetabular shell. As such, the modular acetabular bearing assembly, and its method of manufacture, eliminate all contact between any polymer surface on the composite bearing insert and any metal surface on the acetabular shell. The modularity of the assembly facilitates the interchangeability of various composite bearing inserts within an acetabular shell which is fixed to the acetabulum of a patient.