Chapter 3 - Packaging and Sterilization of UHMWPE

Abstract

This chapter reviews the historical and contemporary packaging and sterilization methods for ultra-high molecular weight polyethylene (UHMWPE). All of the sterilization methods employed by the orthopedic community fulfill their intended purpose, namely the eradication of bacterial agents, which may result in sepsis and premature revision. The diverse sterilization methods in current use reflect the lack of scientific consensus as to which of the currently favored sterilization methods provides the most advantageous long-term UHMWPE product for the ultimate user, namely the patient. UHMWPE components for joint replacement have been stored in air-permeable packaging and gamma sterilized with a nominal dose of 25 kGy. There are many types of barrier packaging currently in use by the orthopedic industry. The details about current packaging systems for orthopedic components are proprietary but basically consist of evacuating the air from the packaging and backfilling with an inert gas. Gamma sterilization of UHMWPE in air permeable packaging was the norm in orthopedics. Orthopedic companies for UHMWPE components employ a broad range of sterilization and packaging methods. For gamma sterilization, barrier-packaging methods have been widely adopted and, until recently, were thought to satisfactorily address the historical problem of oxidation during shelf aging.