Which property of highly cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) explains its superior wear resistance compared with conventional polyethylene in total hip arthroplasty?

• A Increased crystallinity following gamma irradiation in air
• B Cross-linking of polymer chains by gamma irradiation, which reduces chain mobility and adhesive-abrasive wear ✓
• C Addition of carbon fibre reinforcement increasing tensile strength
• D Lower elastic modulus allowing better load distribution across the acetabulum

Explanation

Highly cross-linked polyethylene is produced by gamma or electron beam irradiation that creates covalent bonds between polymer chains, markedly reducing wear in hip simulator studies and clinical registries. The trade-off is reduced fatigue strength and toughness, which is why conventional polyethylene may still be preferred in some total knees. Gamma irradiation in air causes oxidation and embrittlement, which is avoided rather than desired.

Reference: Miller's Review of Orthopaedics, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.