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Expert had firm grip on Rule 702

The US Court of Appeals for the Federal Circuit reversed an exclusion of expert testimony and grant of judgment as a matter of law, finding that the district court improperly conflated admissibility with credibility and weight of the evidence. Barry v. DePuy Synthes Companies, et al., Case Nos. 023-2226; -2234 (Fed. Cir. Jan. 20, 2026) (Prost, Taranto, Stark, JJ.) (Prost, J., dissenting).

Mark Barry owns patents covering surgical techniques and tools for treating spinal deformities. Barry sued DePuy alleging that DePuy induced surgeons to infringe the patents. The patents describe tools and methods, including levers, for applying force to vertebrae to realign the spinal column. Two of the patents required the presence of a “handle means,” which the district court construed as “a part that is designed especially to be grasped by the hand.”

At trial, Barry relied on two experts. His infringement expert, Dr. Walid Yassir, testified that DePuy’s accused tools could be assembled and used in infringing configurations and that certain components (or linked assemblies) constituted the claimed “handle means” under the court’s construction. Barry also offered expert testimony from Dr. David Neal, who conducted a surgeon survey to estimate how often DePuy’s tools were used in infringing configurations, which in turn supported Barry’s damages case.

Although the district court had denied DePuy’s pretrial Daubert motions regarding Barry’s experts, it reversed course mid-trial. The court excluded Yassir’s testimony on the ground that he contradicted the court’s claim construction by equating “handle means” with parts that must be grasped during assembly. The court also excluded Neal’s survey testimony, concluding that methodological flaws, such as nonprobability sampling and alleged defects in question design, rendered the survey unreliable. Having excluded both experts, the court granted DePuy judgment as a matter of law. Barry appealed.

The Federal Circuit agreed that expert opinion that contradicts a court’s claim construction would not be helpful to a jury and should be excluded under Rule 702. The Court found, however, that Yassir did not contradict the court’s construction but instead applied it in a manner a reasonable factfinder could accept or reject – a disputed application that DePuy challenged on cross-examination. However, DePuy did not object to Yassir’s direct testimony despite having secured a pretrial ruling barring evidence inconsistent with the claim construction.

The Federal Circuit concluded that Yassir’s testimony did not contradict the court’s claim construction but rather exposed areas of tension and potential weakness in how Yassir applied that construction to the accused devices. The Court explained that DePuy’s questioning elicited testimony about what could constitute a “handle means” that went to the credibility and persuasiveness of Yassir’s opinions, not their admissibility. The Court rejected the district court’s reliance on isolated testimonial snippets divorced from their surrounding explanations, noting that ordinary ambiguities and concessions revealed through adversarial questioning are for the jury to evaluate and do not convert an expert’s application of a claim construction into an impermissible contradiction warranting exclusion under Rule 702.

The Federal Circuit likewise held that the district court abused [...]

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Judicial Bias and Erroneous Admission of Expert Testimony Prompt Case Reassignment

The US Court of Appeals for the Federal Circuit reversed a district court’s decision to admit expert testimony and remanded the case to a different judge, noting that “from the moment this case fell in his lap, the trial judge’s statements indicate that he did not intend to manage a fair trial with respect to the issues in this case.” Trudell Medical Intl., Inc. v. D R Burton Healthcare, LLC, Case Nos. 23-1777; -1779 (Fed. Cir. Feb. 7, 2025) (Moore, C.J.; Chen, Stoll, JJ.)

Trudell Medical sued D R Burton Healthcare for infringement of a patent directed to respiratory treatment devices. Leading up to trial, Trudell filed a motion in limine seeking to exclude testimony from Dr. John Collins on invalidity and noninfringement. At the pre-trial conference, the court denied the motion in limine. A few days later, however, on the first day of trial, the district court reversed itself and granted the motion in limine after Trudell filed a motion for reconsideration. Moments later, the district court indicated that it would reserve a ruling on the motion until the end of Trudell’s case.

On the third and final day of trial, the district court ruled that Collins was allowed to testify. After trial, the jury returned a verdict that the asserted claims were valid but not infringed. Trudell appealed.

Trudell argued that the district court erred in allowing Collins to testify. The Federal Circuit indicated that it reviews a district court’s decision to admit or exclude evidence under the law of the regional circuit – here, the Fourth Circuit, which applies an abuse of discretion standard. Trudell argued that because Collins did not timely serve an expert report on noninfringement and the failure to do so was neither substantially justified nor harmless, the district court abused its discretion in allowing the testimony. Although D R Burton had filed a seven-page declaration from Collins in support of its opposition to summary judgment of infringement, Trudell argued that it was afforded no opportunity to depose Collins regarding the declaration and was therefore prejudiced by the allowance of the testimony. Trudell argued that the admitted testimony also exceeded the scope of the declaration and was “untethered from the district court’s claim constructions.”

The Federal Circuit agreed, finding that the district court abused its discretion in allowing Collins’s noninfringement testimony because D R Burton did not disclose Collins’ noninfringement opinion in a timely expert report as required by Rule 26. Regarding the declaration, the Court found that it was submitted a month after the close of discovery and therefore was not timely served. The Court concluded that the proper remedy was exclusion of Collins’ noninfringement testimony absent a showing that the failure to disclose was either substantially justified or harmless.

The Federal Circuit affirmed the denial of Trudell’s post-trial motion seeking a finding of infringement. While the Court agreed that without Collins’ testimony there was minimal evidence to support noninfringement, the jury would still have been free to discredit the testimony of Trudell’s [...]

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Expert had firm grip on Rule 702

Judicial Bias and Erroneous Admission of Expert Testimony Prompt Case Reassignment

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