We hypothesized that a vitamin E-treated polyethylene articulating liner had lower femoral head penetration than a conventional liner.
Fifty-one patients with primary hip osteoarthritis were randomized to an uncemented cup with either vitamin E-treated highly cross-linked polyethylene (HXLPE) (vitamin-e group, n = 25) or a standard HXLPE liner (control group, n = 26) and followed for two years after surgery. The outcome variable was polyethylene (PE) linear head penetration, measured with radiostereometry (RSA).
The head penetration in x- (medial/lateral) and y- (vertical) axes was significantly lower for the vitamin E-treated liner up to two years with a mean difference between the groups of 0.10 mm (95 % CI 0.04-0.18) and 0.08 mm (95 % CI 0.01-0.15), respectively. The initial total penetration was lower for the vitamin-E group but did not reach statistical significance at two years with a mean difference between the groups of 0.07 mm (95 % CI -0.001 to 0.15, p = 0.09). We found no differences in clinical outcome between the groups.
In this prospective, randomized, controlled trial on a new vitamin-E diffused HXLPE liner we found, compared to a conventional HXLPE liner, lower initial head penetration and lower superior and medial wear. A longer follow-up than two years is necessary to demonstrate lower overall head penetration in vitamin-E liners compared to contemporary highly cross-linked PE.