Product sterility problems, Good

In practical terms a pass in the Test for Sterility should not be perceived to be of any more significance than any other successful measure of compliance with microbiological or physical standards or controls applicable to the manufacture of sterile products. A pass in the Test for Sterility must not be allowed to overrule any failure to comply with other environmental or control standard(s) because it is quite possible to pass the Test and still have a significant number of non-sterile units in the batch. On the other hand, a failed Test for Sterility is likely to be a good indicator of a genuine problem that has not been disclosed by some other microbiological or physical means. 

Since reducing friction is paramount in the choice of socket material, a logical first choice (and one that was made 40 years ago) would be PTFE. However, the cold flow of the polymer near body temperature (see Section 9.7) is undesirable. UHMWPE has a good combination of lubricity and mechanical stability. There are still problems of degradation, especially along grain boundaries that may remain from the compression molding process as well as persistent by-products from the sterilization step. 

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