Systematic Reviews and Meta-Analyses in Litigation, Part 2

Daubert in Knee’d

In a recent federal court case, adjudicating a plaintiff’s Rule 702 challenge to defense expert witnesses, the trial judge considered plaintiff’s claim that the challenged witness had deviated from PRISM guidelines[1] for systematic reviews, and thus presumably had deviated from the standard of care required of expert witnesses giving opinions about causal conclusions.

Batty v. Zimmer, Inc., MDL No. 2272, Master Docket No. 11 C 5468, No. 12 C 6279, 2015 WL 5050214 (N.D. Ill. Aug. 25, 2015) [cited as Batty I]. The trial judge, the Hon. Rebecca R. Pallmeyer, denied plaintiff’s motion to exclude the allegedly deviant witness, but appeared to accept the premise of the plaintiff’s argument that an expert witness’s opinion should be reached in the manner of a carefully constructed systematic review.[2] The trial court’s careful review of the challenged witness’s report and deposition testimony revealed that there had mean no meaningful departure from the standards put forward for systematic reviews. SeeSystematic Reviews and Meta-Analyses in Litigation” (Feb. 5, 2016).

Two days later, the same federal judge addressed a different set of objections by the same plaintiff to two other of the defendant’s, Zimmer Inc.’s, expert witnesses, Dr. Stuart Goodman and Dr. Timothy Wright. Batty v. Zimmer, Inc., MDL No. 2272, Master Docket No. 11 C 5468, No. 12 C 6279, 2015 WL 5095727, (N.D. Ill. Aug. 27, 2015) [cited as Batty II]. Once again, plaintiff Batty argued for the necessity of adherence to systematic review principles. According to Batty, Dr. Wright’s opinion, based upon his review of the clinical literature, was scientifically and legally unreliable because he had not conducted a proper systematic review. Plaintiff alleged that Dr. Wright’s review selectively “cherry picked” favorable studies to buttress his opinion, in violation of systematic review guidelines. The trial court, which had assumed that a systematic review was the appropriate “methodology” for Dr. Vitale, in Batty I, refused to sustain the plaintiff’s challenge in Batty II, in large part because the challenged witness, Dr. Wright, had not claimed to have performed a systematic or comprehensive review, and so his failure to follow the standard methodology did not require the exclusion of his opinion at trial. Batty II at *3.

The plaintiff never argued that Dr. Wright misinterpreted any of his selected studies upon which he relied, and the trial judge thus suggested that Dr. Wright’s discussion of the studies, even if a partial, selected group of studies, would be helpful to the jury. The trial court thus left the plaintiff to her cross-examination to highlight Dr. Wright’s selectivity and lack of comprehensiveness. Apparently, in the trial judge’s view, this expert witness’s failure to address contrary studies did not render his testimony unreliable under “Daubert scrutiny.” Batty II at *3.

Of course, it is no longer the Daubert judicial decision that mandates scrutiny of expert witness opinion testimony, but Federal Rule of Evidence 702. Perhaps it was telling that when the trial court backed away from its assumption, made in Batty I, that guidelines or standards for systematic reviews should inform a Rule 702 analysis, the court cited Daubert, a judicial opinion superseded by an Act of Congress, in 2000. The trial judge’s approach, in Batty II, threatens to make gatekeeping meaningless by deferring to the expert witness’s invocation of personal, idiosyncratic, non-scientific standards. Furthermore, the Batty II approach threatens to eviscerate gatekeeping for clinical practitioners who remain blithely unaware of advances in epidemiology and evidence-based medicine. The upshot of Batty I and II combined seems to be that systematic review principles apply to clinical expert witnesses only if those witness choose to be bound by such principles. If this is indeed what the trial court intended, then it is jurisprudential nonsense.

The trial court, in Batty II, exercised a more searching approach, however, to Dr. Wright’s own implant failure analysis, which he relied upon in an attempt to rebut plaintiff’s claim of defective design. The plaintiff claimed that the load-bearing polymer surfaces of the artificial knee implant experienced undue deformation. Dr. Wright’s study found little or no deformation on the load bearing polymer surfaces of the eight retrieved artificial joints. Batty II at *4.

Dr. Wright assessed deformation qualitatively, not quantitatively, through the use of a “colormetric map of deformation” of the polymer surface. Dr. Wright, however, provided no scale to define or assess how much deformation was represented by the different colors in his study. Notwithstanding the lack of any metric, Dr. Wright concluded that his findings, based upon eight retrieved implants, “suggested” that the kind of surface failing claimed by plaintiff was a “rare event.”

The trial court had little difficulty in concluding that Dr. Wright’s evidentiary base was insufficient, as was his presentation of the study’s data and inferences. The challenged witness failed to explain how his conclusions followed from his data, and thus his proffered testimony fell into the “ipse dixit” category of inadmissible opinion testimony. General Electric v. Joiner, 522 U.S. 136, 146 (1997). In the face of the challenge to his opinions, Dr. Wright supplemented his retrieval study with additional scans of surficial implant wear patterns, but he failed again to show the similarity of previous use and failure conditions in the patients from whom these implants were retrieved and the plaintiff’s case (which supposedly involved aseptic loosening). Furthermore, Dr. Wright’s interpretation of his own retrieval study was inadequate in the trial court’s view because he had failed to rule out other modes of implant failure, in which the polyethylene surface would have been preserved. Because, even as supplemented, Dr. Wright’s study failed to support his proffered opinions, the court held that his opinions, based upon his retrieval study had to be excluded under Rule 702. The trial court did not address the Rule 703 implications for Dr. Wright’s reliance upon a study that was poorly designed and explained, and which lacked the ability to support his contention that the claimed mode of implant failure was a “rare” event. Batty II at *4 – 5.


[1] See David Moher , Alessandro Liberati, Jennifer Tetzlaff, Douglas G. Altman, & The PRISMA Group, “Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement,” 6 PLoS Med e1000097 (2009) [PRISMA].

[2] Batty v. Zimmer, Inc., MDL No. 2272, Master Docket No. 11 C 5468, No. 12 C 6279, 2015 WL 5050214 (N.D. Ill. Aug. 25, 2015).

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