The Effect of Neutron Radiation on Conventional and Highly Cross-Linked Ultrahigh-Molecular-Weight Polyethylene Wear

The effects of a sarcoma therapy dose level neutron radiation on oxidation and wear were compared between conventional (N2\Vac, Stryker Orthopedics, Mahwah, NJ) and highly cross-linked (Crossfire, Stryker Orthopedics) ultrahigh-molecular-weight polyethylene acetabular liners. Liners were exposed to 15 Gy, a typical sarcoma treatment dose. Wear testing was conducted on a hip simulator. Transvinylene and oxidation indices were measured to determine if significant radiolytic reactions and oxidation occurred after the neutron beam exposure. The neutron bombardment produced further oxidation in both N2\Vac and Crossfire liners. Surprisingly, neutron radiation caused 62% increase in wear for N2\Vac but 0% change for the Crossfire acetabular liners. This study suggested that when joint implants are exposed to neutron beam radiation therapy, the conventional polyethylene liner is at risk for rapid wear.