Because of the difficult legal and procedural issues often facing the court and jury, any medical-device or pharmaceutical product-liability case taken all the way to a final verdict is unlikely to be a neat and tidy affair. It may not even be a onetime affair if the first jury is unable to reach consensus on the myriad negligence and strict-liability claims brought in each action.

Valentine v. Baxter Healthcare Corp., 81 Cal.Rptr.2d 252 (Jan. 7, 1999), is a case that involved such complexities at the trial level. Even practitioners who last parsed the distinction between negligent vs. strict-liability failure-to-warn claims in a first-year torts class will commiserate with courts that have had to determine the interrelationship between the two during trial -- and with counsel who have had to explain the distinctions to lay jurors.

The Valentine decision by the 1st District Court of Appeal, however, may be a significant step toward bringing order to the tumult of product-liability trials, where numerous theories of recovery are entwined and there is a real risk that juries may be unable to reach a verdict on all the claims, or may reach inconsistent verdicts.

In California, a product manufacturer generally may be sued under a strict-liability theory for placing a product on the market without adequately warning of dangers that were "known or scientifically knowable" at the time of distribution. Carlin v. Superior Court, 13 Cal.4th 1104 (1996). Though the claim is technically one for strict liability, the Carlin court noted that determining whether a product's dangers were known or knowable "infuses some negligence concepts" into the strict-liability claim.

Moreover, a plaintiff may also sue the same manufacturer for negligently failing to warn of dangers that a reasonable manufacturer would have known and warned about. Anderson v. Owens-Corning Fiberglas Corp., 53 Cal.3d 987 (1991). Because of the similarities between the two standards and the incorporation of "some negligence concepts" into the strict-liability claim, parties and courts often treat the claims interchangeably. Because of the similarities between the two standards and the incorporation of "some negligence concepts" into the strict-liability claim, parties and courts often treat the claims interchangeably.

Valentine involved claims against a medical-device manufacturer for injuries that allegedly resulted from its breast implants. The plaintiff asserted, among other things, both negligent and strict-liability failure-to-warn claims, and the case ultimately went to a jury twice. At the close of the first trial, the jury answered a special-verdict form and found for the defendant manufacturer on a strict-liability failure-to-warn claim.

However, on the same special-verdict form, the jury also found for the plaintiff on a question that inquired whether the manufacturer had exercised reasonable care in its product warnings. Because the jury also had hung on a question regarding causation, the court declared a "partial mistrial."

Eventually, the negligent failure-to-warn claim was retried and submitted to a second jury. After seven days of deliberation, the second jury also hung on that claim, and a mistrial was again declared.

Instead of a third trial, the court granted the manufacturer's motion for a directed verdict on the claim and, not surprisingly, an appeal followed.

The Valentine court first looked at the procedural decisions made by the trial judge when he entered judgment on the verdicts the first jury was able to reach and declared a "partial mistrial" as to the remaining issues.

Trial courts have been vested with the express authority to use various procedural devices to partially resolve the cases before them while leaving the remainder for subsequent disposition -- save in one, perhaps surprising, respect. For example, it has long been recognized that trial courts can weed out causes of action at the pleading stage through demurrer, Code of Civil Procedure Section 430.50, or following discovery on a motion for summary adjudication or "partial summary judgment," Code of Civil Procedure Section 437c(f).

Courts also have long been recognized as possessing the power to order the bifurcation of a trial and to permit the jury to resolve claims or defenses in a piecemeal fashion, Code of Civil Procedure Sections 597, 597.5, 598, to order a partial nonsuit on some of the claims or defenses and postpone judgment until after the jury's verdict has resolved the remaining issues, or to order a directed verdict on some of the issues presented, Code of Civil Procedure Sections 581c(b), 630(b).

Despite these broad powers to partially resolve issues, a glimmer of uncertainty remained until Valentine: What is the appropriate procedure when the jury hangs on one or more claims, but successfully resolves others? Does the entire case get sent to a second jury, or does the court only retry the claims on which the first jury hung?

In Valentine, the court affirmed the trial court's power to declare a "partial mistrial" as to those claims on which the jury could not reach a verdict, thus obviating the cost and expense of retrying the entire action. After the second jury disposes of the mistried claims, the judge simply enters one final judgment that is a composite of the partial resolutions reached by each jury.

The Valentine court also examined the trial judge's decision that the first jury's defense verdict on the strict-liability failure-to-warn claim mandated a directed defense verdict on the negligent failure-to-warn claim. In determining that the trial court had properly directed a verdict for the defendant on the negligent failure-to-warn claim, the appellate court first looked at the different requirements of each claim.

As an initial matter, the court noted that there was little, if any, difference between a "warning to ordinary users about a product use that involves a substantial danger" and a "warning about a product that is dangerous or likely to be dangerous for its intended use." Because the court concluded that the manufacturer's duty under strict liability was to warn of "potential" risks that are known or knowable, it concluded that that duty subsumed the duty under negligence to warn of facts that make the product likely or "probably" dangerous for its intended use.

Likewise, the court compared the strict-liability requirement of a warning about "known or scientifically knowable" risks vs. the negligence requirement of a warning about risks that the manufacturer "knows or has reason to know." Again, the court determined that, to the extent there was a difference, the former subsumed the latter.

Because of this interrelationship between the two claims, the appellate court concluded that a defense verdict on a strict-liability failure-to-warn claim mandated a defense verdict on a negligent failure-to-warn claim, because whatever differences exist between the two, the strict-liability claim is the "lesser included" claim of a negligent failure-to-warn claim.

One other interesting element of the Valentine decision relates to the plaintiff's request for an instruction that the manufacturer had a separate duty to conduct long-term testing before it sold its breast implants. The plaintiff contended that if the breast-implant manufacturer had conducted "appropriate testing for long term effects," the manufacturer would have discovered information about breast-implant risks that was different from what was known or knowable in the scientific community at the time the implants were manufactured and distributed.

The Valentine court noted that by the time of the plaintiff's surgery in 1975, the state of science was such that a reasonable manufacturer would have concluded that silicone was safe for use in human implants and that by the time of the second trial, more than 30 controlled epidemiological studies showed no statistically significant risk of systemic diseases such as the one that plaintiff allegedly developed.

In short, time had failed to reveal that breast implants contain a hidden risk of systemic disease, and the court concluded that it would be "beyond the pale" to nevertheless fault manufacturers for breaching an independent duty to conduct long-term testing.

Though the situation was not presented in Valentine, the court's reasoning on the lack of an independent duty to conduct long-term testing should apply equally well, even in situations where time reveals some hidden risk that was unknown and unknowable at the time of manufacture. Even if the passage of time reveals a product's hidden and previously unknown risks, the inherently speculative nature of proving that tests would have shown the ultimately discovered risk had they been conducted is a tenuous and perhaps unfair basis on which to attach liability.

Valentine's affirmance of the trial court's power to declare partial mistrials, combined with its conclusion that a defense verdict on a strict-liability failure-to-warn claim mandates a defense verdict on a negligent failure-to-warn claim, should give trial courts two useful tools to transform legally complex product-liability special verdicts into judgments.