On February 12, 2016, the FDA issued draft guidance for the use of ultrahigh molecular weight polyethylene (UHMWPE) in orthopedic devices. The draft guidance is open for public comment for the next 90 days. According to the draft guidance, the recommendations apply to “class II and class III devices intended for orthopedic applications.” The guidance applies to four types of UHMWPE materials: conventional UHMWPE, highly crosslinked UHMWPE (XLPE), Vitamin E highly crosslinked UHMWPE (VEPE), and non-conventional UHMWPE.
The draft guidance provides FDA recommendations on the “information and testing to submit in pre-market notifications (510(k)s), de novo requests, premarket approval (PMA) applications, humanitarian device exemptions (HDEs), and investigational device exemptions (IDEs).” The draft guidance provides recommendations on reporting material characterization, biocompatability, and shelf life when submitting those documents. A brief summary of some of these recommendations follows.
Material Testing:
[The FDA recommends characterizing] the following properties of the material: crosslink density, trans-vinylene index (TVI), oxidation index (OI), crystallinity, melting temperature, and free radical concentration. If the measured values lie within the normal range, determined by comparison to literature (i.e., for de novo, PMA, HDE, or IDE) or a predicate device with the same intended use (i.e., 510(k)), no additional information will typically be requested. However, for some properties, FDA recommends that certain results be achieved.
The draft guidance provides examples of properties where certain results should be achieved. The draft guidance notes that some properties “are comparative in nature. When submitted in a 510(k), the results should be compared to a predicate device with the same intended use.”
Biocompatability:
For Class II devices, if the subject device has identical UHMWPE materials and manufacturing processes as a predicate device, with the same type and duration of patient contact, [the FDA] recommend that you identify the predicate device as part of your biocompatibility evaluation in lieu of providing specific testing.
For other class II devices, de novos, and class III devices, the guidance directs the applicant to evaluate the device’s material based on Blue Book Memorandum #G95-1.
Shelf Life:
The FDA recommends not packaging “UHMWPE materials containing unstable free radicals in air-permeable packaging because shelf-aging may degrade the mechanical properties of UHMWPE.”
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