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This post is from the non-Reed Smith side of the blog.

If you skim through our Daubert posts, they are usually celebrating successful defense challenges to plaintiffs’ experts.  We have posts on repeat offenders like Blume and Parisian.  We have posts on unqualified experts – those with no educational or professional experience on the topics they wish to opine.  We have lots of posts on unsupported opinions, insufficient data and unreliable methodology.  And there are posts on experts who seek to invade the province of the jury (those who want to interpret corporate documents) or the court (those whose vocabulary include things like negligent and reckless).

It is less common for plaintiffs to file Daubert motions seeking to exclude defense experts. But that is just what happened in In re Zimmer Nexgen Knee Implant Prods. Liab. Litig., 2015 WL 5050214 (N.D. Ill. Aug. 25, 2015).  Which means today we get to celebrate the denial of a Daubert motion – a Daubert win from a slightly different angle.

On of the issues in the Zimmer Nexgen litigation is whether defendant’s high-flex knee implants have an artificially higher failure rate than their equivalent counterparts.  Id. at *1.  To dispute such a conclusion, defendant proffered testimony from an expert epidemiologist, Dr. Vitale, who conducted a literature review from which he concluded that the studies relied on by plaintiffs were outliers.  Id.  Plaintiffs challenged both the qualifications and methodology of defendant’s expert.

On qualification, plaintiffs focused on the fact that defendant’s expert is a pediatric spine surgeon; that he does not specialize in knee replacements.  Plaintiffs, however, overlooked that Dr. Vitale also has a master’s degree in public health with an emphasis on clinical outcomes research, an area in which he has also published.  Id. at *4.  His testimony and conclusions were not based on his experience as a pediatric spine surgeon, but rather his “epidemiological and general clinical research expertise.” Id. at *5.

The analysis of Dr. Vitale’s research methodology is more complex and multi-faceted.  We’ll walk through the important aspects, but the overall conclusion of the court is that his methodology was reliable and admissible.  Those aspects of his research and conclusions plaintiffs take issue with do not warrant exclusion, but rather can be tested through cross-examination.

What was his research?  Dr. Vitale conducted a “formal systematic review of the literature.”  (He reviewed other data as well that plaintiffs did not challenge).  In the simplest terms, Dr. Vitale used search terms to find relevant literature on the topic at issue or to create a “neutral snapshot of the existing research on a particular question.”  Id. at *3.  Irrelevant studies – those that don’t address the research topic – are omitted, as are studies that have other flaws.  Id. at *4.  The remaining literature is reviewed and scored and the research usually concludes with summary statistics and qualitative findings.  Id. at *3.  Plaintiffs did not challenge that a formal systematic literature review is an invalid methodology, but rather that the way Dr. Vitale conducted his review made it unreliable.

Plaintiffs’ first argument was that Dr. Vitale failed to comply with internationally recognized guidelines for systematic reviews known as PRISMA.  Id. at *6.  The court was skeptical of plaintiffs’ argument from the outset considering plaintiffs’ own expert neglected to cite PRISMA, “which casts some doubt on Plaintiff’s claim of widespread acceptance.”  Id  at *7.  More importantly, the court noted that PRISMA is really about the “reporting” of systematic reviews, not their “conduct.” Id. While reporting is important for publication, it isn’t really the cornerstone of a Daubert analysis.  So, failing to report his results graphically, for example, isn’t something that calls into question the reliability of Dr. Vitale’s research.  Id. at *8.  Nor was it fatal that Dr. Vitale’s report did not include an explicit statement of his research question.  Again, this is important for publication that subsequent researchers can determine if the analysis is applicable to their interests.  In the context of litigation, Dr. Vitale’s research objective was clear – both from his deposition testimony and the totality of his report.  Id. at *7.  Would Dr. Vitale’s research and conclusions have to be reported differently to pass peer review for publication?  Maybe.  But that’s not Daubert.

Plaintiffs next challenged Dr. Vitale’s opinion on the ground that he commingled heterogeneous studies – studies of varying lengths, size, follow-up, etc.  Id. at *9.  While heterogeneity can be problematic, Dr. Vitale’s report acknowledged that “the variability among study cohorts precludes aggregate analysis.”  Id.  It is up to the plaintiffs to cross-examine Dr. Vitale regarding this inclusion and exclusion of certain studies, it is not the court’s role “to determine whether Dr. Vitale’s ultimate conclusion is the right one.”  Id.  That’s for the jury.

Plaintiffs also alleged that Dr. Vitale “cherry-picked” the studies he included in his review.  Maybe a little pot calling the kettle on this one.  There is no shortage of instances where defendants have challenged plaintiffs’ experts on this basis.  Here, however, the court did not find evidence of inappropriate selection or exclusion by Dr. Vitale.  First, Dr. Vitale did not ignore the studies as plaintiffs contend.  All were cited and discussed in the report, including the reasons why they were excluded.  The court took note of Dr. Vitale’s even-handed exclusion, for objective scientific reasons, of studies that were both favorable and unfavorable to the defense position.  Id. at *10-11.  While there may have been oversights, those should be the topic of cross-examination.  There was no basis to conclude that Dr. Vitale attempted to distort the data such that his results should be excluded as unreliable.  Id.

Finally, plaintiffs challenged Dr. Vitale’s subsequent analysis on range of motion.  In response to Dr. Vitale’s initial report, plaintiffs claimed that he had failed to consider the range of motion achieved by the patients in the studies (plaintiffs contend that failure rates may be higher for those who achieve high flexion as opposed to those who do not).  So, Dr. Vitale went back to look at that issue.  Plaintiff then claimed that Dr. Vitale “is required to conduct a completely new systematic review with a search driven by this new question.”  Id. at *12.  If we understand correctly, plaintiffs’ position is that because the defense expert did a subsequent analysis to
respond to plaintiffs’ criticism, he has to start from scratch and do his analysis based on plaintiffs’ stated objective.  The court understood that too:


Dr. Vitale simply revisited those studies to determine
whether [plaintiffs’] attack had merit and updated his data accordingly.  The court does not agree with Plaintiffs that
this subsequent analysis was invalid or unreliable.


So, when the bellwether trials in the Zimmer NexGen litigation begin, the jury will be able to hear from Dr. Vitale that in his expert epidemiological opinion, the studies relied on by plaintiffs are outliers.  He’ll be allowed to present his methodology and his conclusions with a stamp of approval from the judge that he is both qualified to do so and that he used a reliable methodology.  Sure, plaintiffs can pick around the edges – but most of their arguments have been rejected.  It is slightly odd to be lauding the denial of a Daubert motion, but Zimmer’s expert report in this case seems to stand head and shoulders above what we often see from plaintiffs. While we may be the ones more often challenging things like cherry-picking and commingling, it’s nice to see that when plaintiffs tried to turn the table – the defendant still came out on top.