Polyethylene (abbreviation PE) is a thermoplastic made by chain polymerisation of ethene [CH2=CH2], from which prosthetic components (e.g. inserts) can be produced. In arthroplasty, ultra high molecular weight polyethylene (UHMWPE) is usually used. This can subsequently be modified by irradiating and coupling to antioxidants. Also refer to hXLPE or mXLPE.