This is a report of a unique case of bilateral simultaneous total knee arthroplasties in which one tibial liner failed dramatically, whereas the other liner showed minimal evidence of wear. This unique case allows isolation of component factors as the primary contributing etiology to failure. The differentiating characteristic was the method of sterilization and the shelf life of the polyethylene liner. The insert that showed minimal wear was sterilized with γ radiation in a barrier package and had a shelf life of less than 1 year, whereas the insert that failed dramatically was sterilized in air and had a shelf life of more than 5 years. This case provides a dramatic example of the potential detrimental effects of manufacturing details on the performance of orthopedic implants, particularly polyethylene inserts.