2 - From Ethylene Gas to UHMWPE Component: The Process of Producing Orthopedic Implants

Abstract

At a conceptual level, polyethylene consists only of carbon and hydrogen, as was described in the previous chapter. However, if the discussion of polyethylene is to proceed from ideal abstractions to actual physical implants, three “real world” steps need to occur. First, the UHMWPE must be polymerized from ethylene gas. Second, the polymerized UHMWPE, in the form of resin powder, needs to be consolidated into a sheet, rod, or near-net shaped implant. Finally, in most instances, the UHMWPE implant needs to be machined into its final shape. A small subset of implants are consolidated into their final form directly, in a process known as direct compression molding, without need of additional machining.