Today, the summer solstice, is one of our favorite days of the year.  It’s the first official day of summer, and readers in the U.S. will have anywhere from 14-16 hours of daylight (the farther north, the more daylight). We hope you get to enjoy some of the summer sunshine today—or at least this weekend.  As the late, great, Brian Wilson put it, “Sunshine, can’t get enough sunshine, I’m following the sunshine, everywhere I go.”

On this (hopefully) sunny, summer day, we’re pleased to report some good news on the Rule 702 front out of the Eighth Circuit.  About a year ago we posted on a decision from the District of Minnesota excluding a frequent-flier plaintiff expert (Mari Truman) in a medical device case.  The opinion was a strong example of a district court applying the 2023 amendments to Fed. R. Civ. P. 702.  The plaintiff appealed the district court’s exclusion of their expert and the grant of summary judgment.  We’ve been watching the appeal since it would give the Eighth Circuit an opportunity to reconsider some of its prior Rule 702 precedent in light of the 2023 amendments (we previously called out the Eighth Circuit as a prime example of courts being reluctant to follow the strictures of Rule 702). 

The opinion didn’t go as far as we hoped—as the court did not squarely address how some of its earlier decisions appeared to relegate the district court’s gatekeeping role under 702. But, it is a published opinion that recognizes the impact of the 2023 amendments and squarely affirms a district court’s rigorous analysis under Rule 702 excluding junk, litigation-driven opinions. Sprafka v. Medical Device Business Services, Inc., No. 24-1874, 2025 WL 15753583 (8th Cir. June 4, 2025). We’ll definitely take that.

We previously provided a detailed summary of the district court’s analysis, but in general the district court held that the plaintiff’s expert opinions that the defendant’s knee replacement system had a higher failure rate than other devices were not based on independent research, were developed solely for litigation, were not supported by any reliable data, and did not include any information on what modifications to the device would have prevented the alleged defect. As it began its review of the district court’s decision under the abuse of discretion standard, the Eighth Circuit started with the recent amendments to Rule 702:

In 2023, Rule 702 was amended to clarify and emphasize that expert testimony may not be admitted unless the proponent demonstrates to the court that it is more likely than not that the proffered testimony meets the admissibility requirements set forth in the rule.  Contrary to [plaintiff’s] argument that the district court went beyond its appropriate gatekeeping function, after Rule 702’s recent amendments courts continue to have a gatekeeping role to ensure that evidence admitted in a case is both relevant and reliable.

Id. at *3 (internal quotations and citations omitted).

The Eighth Circuit then discussed the district court’s analysis and agreed with its conclusions that the expert’s opinions did not satisfy the requirements of amended Rule 702. The opinions “were not subjected to typical scientific scrutiny through peer review and publication,” but “were prepared for litigation and based primarily on two published case studies with limited participants.” Id.  The expert acknowledged that the case studies she relied on did not establish the rate of alleged defect for the knee replacement system—which reinforced the speculative nature of her opinions.  The expert also relied on testimony from the treating physician (a non-retained expert for plaintiff) that the physician and his partners had observed a high rate of revision surgeries with the defendant’s knee replacement system. But neither the treating physician nor the plaintiff’s expert knew the actual rate of purported revisions with the system that they had observed.  And registry data that Dr. Truman relied on showed in fact that the defendant’s knee replacement system had a similar or lower rate of revision than other available knee replacement systems.  Ultimately, the expert’s opinion that the defendant’s system was defective was an improper legal conclusion that was “properly disregarded.”  Id. “Without a scientific or reliable basis to establish the rate of debonding of the [defendant’s] knee replacement system, or data showing how the . . . system compares with other devices on the market, Dr. Truman’s opinions lack reliability.”  Id.  The Eighth Circuit held that the district court did not abuse its discretion in excluding Dr. Truman’s opinions under Rule 702.

The Eighth Circuit also addressed plaintiff’s argument that, even if Dr. Truman’s opinions were properly excluded, the district court improperly granted summary judgment because the opinions of a treating physician disclosed as a non-retained expert would allow the jury to find that the knee replacement system was defectively designed.  When the defendant moved for summary judgment on all claims, plaintiff never argued that the treating physician’s opinions, standing alone, were sufficient to support plaintiff’s design defect argument.  Id. at *4.  The district court specifically asked plaintiff if she could survive summary judgment if Dr. Truman’s opinions were excluded, but plaintiff’s counsel “never responded directly to this question.”  Id.  As a result the Eighth Circuit held that plaintiff failed to preserve the argument for appeal.

Finally, the Eighth Circuit on its own raised the question of whether the plaintiff’s failure to warn claim was properly dismissed upon the exclusion of plaintiff’s design defect opinions.  But the court did not have to reach the merits of this question, as it (again) found that the plaintiff did not preserve the question.

In terms of post-amendment Rule 702 precedent from the Eighth Circuit, we’ll call this one a good start. Just like we hope today’s solstice will be a good start for your summer.