Stryker Hip Implant Patent Not Infringed by Competitors

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By Tony Dutra

May 12 — Stryker Corp.'s patent on a socket assembly for hip implants is too narrowly described to cover its competitors' products, the Federal Circuit held in a March 12 decision.

Stryker's problem presents a cautionary tale for patent drafters' specific descriptions of “embodiments” of an invention. The court ruled that the phrase “in a preferred embodiment” applied only to the sentence in which Stryker's patent specification used it.

Stryker was unable to convince the court that the next sentence was meant to be part of the preferred embodiment, which would have meant that its patent claims covered other embodiments—including, presumably, its competitors' products—as well.

The court didn't state a hard-and-fast rule, but said rather that “context reveals” what is merely one embodiment and what is a critical feature of the invention.

Patent prosecutor Courtenay C. Brinckerhoff of Foley & Lardner LLP, Washington, said that drafter should always be careful in any case and not risk that a judge will understand the inventor's intention differently.

“While this type of issue is highly case specific and influenced by the description as a whole, if the ‘in a preferred embodiment' clause were at the start of the paragraph, I might think it applied to the whole paragraph,” she said. “But here, where it is in the middle [of the paragraph], I can see it applying to just that sentence.”

Source Material:

Case below (D.N.J.):No. 2:11-cv-065112013 BL 181321 (claim construction)

U.S. Patent:No. 6,475,243

‘Essentially Midway' Position Key to Claimed Benefit

Stryker Ireland Ltd. and Howmedica Osteonics Corp., subsidiaries of Stryker Corp., sell the Trident acetabular cup system. Stryker sued four competitors in the U.S. District Court for the District of New Jersey, claiming infringement of U.S. Patent No. 6,475,243 by Zimmer's Continuum, Wright Medical Technology Inc.'s Dynasty, DePuy Orthopaedics Inc.'s Duraloc and Smith & Nephew Inc.'s R3 Systems. DePuy was dismissed from the case in June 2014.

Stryker conceded noninfringement after the district court's claim construction and appealed.

The key was a claim term indicating the positioning of two elements as “juxtaposed” with or in “juxtaposition” to one another. The Federal Circuit rejected Stryker's request that it look to dictionary definitions. The court instead focused exclusively on the patent specification.

The court construed the term such that the first element was positioned “essentially midway” in contact with another. The “essentially midway” language was in the sentence after the “in the preferred embodiment” sentence.

The court's precedents teach that claim construction should not “import” a limitation from the specification that is not explicit in the claims. Stryker argued that the court was importing the midway location limitation here.

But the claims' benefit was “effectiveness,” the court said, and that benefit was attributed in the patent as being due to the midway positioning in at least one other place in the specification.

Claiming Doctrine of Equivalents

A secondary issue in the case also tripped up Stryker and provided another cautionary note about pleading infringement.

Stryker knew that it could no longer argue literal infringement because the competitive products didn't meet the “essentially midway” limitation. But Stryker wanted to argue infringement under the “doctrine of equivalents”—that those products gave the same “effectiveness” even with different configurations.

Stryker never explicitly stated infringement contentions that relied on the doctrine though. And the rules for patent practice in the District of New Jersey required it. The lower court didn't allow Stryker to change its contentions late in the litigation.

“Although the result may seem harsh, we find no abuse of discretion in the district court applying its rather clearly stated rule,” the court said.

Judge S. Jay Plager wrote the court's opinion, which was joined by Judges Kathleen M. O'Malley and Evan J. Wallach.

Winston & Strawn LLP represented Stryker. Finnegan, Henderson, Farabow, Garrett & Dunner LLP represented Zimmer. Duane Morris LLP represented Wright Medical. Hunton & Williams LLP represented Smith & Nephew.

To contact the reporter on this story: Tony Dutra in Washington at

To contact the editor responsible for this story: Mike Wilczek in Washington at

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