Highly cross-linked ultrahigh molecular weight polyethylene used in modern acetabular liners achieves its superior wear resistance primarily because:
- A Gamma or electron beam irradiation creates carbon-carbon crosslinks between polymer chains, followed by thermal treatment to eliminate residual free radicals ✓
- B It is compressed at high pressure to increase crystallinity
- C Vitamin E is added as an antioxidant pigment
- D It is remelted to convert the amorphous phase entirely into large crystalline domains
Correct answer: A. Gamma or electron beam irradiation creates carbon-carbon crosslinks between polymer chains, followed by thermal treatment to eliminate residual free radicals
Explanation
Cross-linking is induced by ionizing radiation, which cleaves chains and forms covalent carbon-carbon bonds between them, dramatically reducing adhesive abrasive wear compared with conventional UHMWPE. Residual free radicals left by radiation would cause oxidative embrittlement, so the material is subsequently melted above its melt point (or annealed, or doped with vitamin E) to quench these radicals. Option D confuses melting with recrystallization, and vitamin E is an antioxidant strategy, not a crosslinking method.
Reference: Miller's Review of Orthopaedics, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.