Addressing claim construction issues, the US Court of Appeals for the Federal Circuit reiterated the necessity of reading claims in the context of the written description when they are not clear on their face. Howmedica Osteonics Corp. v. Zimmer, Inc., Case Nos. 15-1232; -1234; -1239 (Fed. Cir., May 12, 2016) (Plager, J).

Howmedica sued three companies for infringing a patent directed to a socket assembly for prosthetic hip implants with claims that required a bearing secured into a shell having a recess and a taper “placed at relative locations such that the effectiveness . . . is maintained.” During claim construction, the defendants argued that the relative location claim language required the recess to be “essentially midway” along the taper, and separately argued that the claims required an additional “sleeve” component. The “essentially midway” position was premised on amendments made during a reexamination that added the “relative location” language to the claims along with a written description passage that described the recess as being essentially midway along the taper. The district court agreed with the defendants on both constructions.

Howmedica sought a stipulated judgment of non-infringement based solely on the “sleeve” construction. The defendants refused and moved for summary judgment based on both the “sleeve” and the “essentially midway” constructions. Howmedica argued that summary judgment with respect to the “essentially midway” construction was not proper because it still had a doctrine of equivalents position. The district court disagreed, finding that Howmedica failed to properly amend its infringement contentions to include the doctrine of equivalents, and that boilerplate equivalents position in Howmedica’s infringement contentions was not sufficient. Howmedica appealed to the Federal Circuit.

On appeal, the Federal Circuit agreed with the “essentially midway” construction. According to the Federal Circuit, because the claims fail to explain how to “place” the elements to maintain effectiveness, one of ordinary skill in the art would naturally look to the written description. After looking to the written description, the Court concluded that the “essentially midway” construction was correct because that was the only arrangement disclosed. On appeal, Howmedica argued that this construction impermissibly limited the claims to the preferred embodiment, ignored written description language that characterized the embodiments as exemplary, and violated the rule of claim differentiation. The Federal Circuit rejected the preferred embodiment argument as misreading the written description. It also gave no effect to the written description’s characterization of its disclosure as merely exemplary. Finally, the Court noted that claim differentiation is merely a rebuttable presumption and found it rebutted in this case.

The Federal Circuit also found no abuse of discretion in the district court’s treatment of Howmedica’s doctrine of equivalents assertion, and affirmed the judgment. As for the “sleeve” construction, the Federal Circuit declined to address the district court’s conclusion, finding the “essentially midway” issue to be dispositive.