CeramTec GmbH v. CoorsTek Bioceramics LLC

Authored by: Jeremy J. Gustrowsky

In a recent decision, the Federal Circuit affirmed the cancellation of CeramTec GmbH’s trademarks for the pink color used in its ceramic hip implant components. CeramTec, a manufacturer of artificial hip parts made from zirconia-toughened alumina (ZTA) ceramic, had obtained U.S. patents—including U.S. Patent 5,830,816—covering the addition of chromium oxide (chromia) to ZTA ceramics. This addition not only improved the material’s hardness but also resulted in a distinctive pink color. CeramTec registered the pink color as a trademark, but competitor CoorsTek Bioceramics LLC challenged the registration, arguing that the color was functional and should not be protected as a trademark.

The court’s analysis centered on the “functionality doctrine,” which prevents trademark law from granting perpetual exclusive rights over useful product features that should remain available for all to use once any relevant patents expire. The court agreed with the Trademark Trial and Appeal Board that CeramTec’s own patents and marketing materials provided strong evidence that the pink color—caused by chromia—was linked to functional improvements in the ceramic’s properties. The Board applied the four Morton-Norwich factors for evaluating functionality, finding that CeramTec’s patents and advertising touted the utilitarian benefits of chromia, and that there was no clear evidence that alternative colors would work as well.

CeramTec argued that more recent testing showed chromia did not actually improve the ceramic’s properties, but the Board found these tests methodologically flawed and incomplete. The court also rejected CeramTec’s claim that the Board improperly shifted the burden of proof, confirming that CoorsTek had met its burden to show the pink color was functional.

Finally, the court addressed CeramTec’s “unclean hands” defense, where CeramTec argued that CoorsTek should not be allowed to challenge the trademark because of its own inconsistent statements about chromia’s benefits. The court clarified that while the unclean hands defense is not categorically barred in these proceedings, the Board acted within its discretion in declining to apply it here, citing the strong public interest in removing functional marks from the trademark register. The decision underscores that product features serving a functional purpose—even if they are visually distinctive—cannot be monopolized through trademark law.