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EXp Blended Antioxidant Technology

StelKast is the first U.S. orthopedic company to provide a highly cross-linked vitamin E blended antioxidant polyethylene, offering superior oxidation resistance in hip and knee implants.

EXp Polyethylene Technology represents an optimal blend of UHMWPE, the antioxidant vitamin E(α-tocopherol), and cross-linking for long-term oxidative stability, preservation of mechanical properties and performance.

  • Unlike other highly cross-linked polyethylenes, EXp requires no thermal processing or infusion of antioxidants to stabilize the material.
  • EXp liners experienced no failures as a result of dynamic impingement testing.
  • The vitamin E blended into the EXp does not elude from the material during extraction studies.
  • The morphology of EXp UHMWPE is consistent with conventional UHMWPE—demonstrating no consolidation defects or voids.


Oxidatively Stable1
EXp UHMWPE is more resistant to oxidation than conventional cross-linked polyethylene
EXp charts OxyStable

Long-Term Stability2
EXp UHMWPE remains resistant to oxidation after 5 million cycles of wear testing and artificial aging
EXp charts longterm


Preserved Mechanical Performance3
EXp UHMWPE retained its mechanical performance after oxidative aging
EXp charts preserved

Reduced Wear4
EXp liners demonstrated a 30% reduction in wear against a 36mm BIOLOX®delta head compared to a 36mm cobalt-chrome head
EXp charts wear

References 1 through 7: Data on file at StelKast. Bench testing is not necessarily indicative of clinical performance.

Download the EXp brochure