                                 In the

    United States Court of Appeals
                  For the Seventh Circuit
                      ____________________
No. 16-3957
IN RE: ZIMMER, NEXGEN KNEE IMPLANT
       PRODUCTS LIABILITY LITIGATION

APPEAL OF: THEODORE F. JOAS and DARLENE A. JOAS
                      ____________________

              Appeal from the United States District Court
         for the Northern District of Illinois, Eastern Division.
             No. 13 C 9216 — Rebecca R. Pallmeyer, Judge.
                      ____________________

      ARGUED MAY 22, 2017 — DECIDED MARCH 8, 2018
                ____________________

   Before FLAUM, EASTERBROOK, and SYKES, Circuit Judges.
    SYKES, Circuit Judge. Theodore Joas underwent a total
knee replacement at a Wisconsin hospital and received a
Zimmer NexGen Flex knee implant. Within a few years, he
began experiencing pain in his new knee. X-rays confirmed
that the implant had loosened and required a surgical fix.
Joas brought a panoply of claims against Zimmer, Inc., the
implant manufacturer. His case was transferred to a multi-
district litigation in the Northern District of Illinois, where it
was eventually treated as a bellwether case. Applying
Wisconsin law, the presiding judge entered summary judg-
ment for Zimmer.
2                                                           No. 16-3957

    Joas asks us to reinstate a single claim based on a theory
of inadequate warning. His appeal raises some unresolved
issues in Wisconsin product-liability law—most notably, the
application of the “learned intermediary” doctrine, which
the Wisconsin Supreme Court has not yet had an opportuni-
ty to address. We predict that the state high court would
follow the lead of other states and adopt this doctrine. We
affirm the judgment.
                            I. Background
     Joas’s suit is the second bellwether case in a multidistrict
litigation concerning Zimmer NexGen Flex knee implants.
Plaintiffs in the litigation allege that they have suffered pain
and loss of movement because the NexGen Flex is prone to
premature loosening. 1
    In 2008 Joas had knee-replacement surgery at a hospital
in Eau Claire, Wisconsin. His surgeon used a Zimmer
NexGen Flex implant. At the time Joas worked for Pepsi
Bottling Group, and his job required him to lift and carry
heavy loads and to squat repeatedly throughout the day.
Soon after the surgery he was able to engage in physical
therapy, return to work, and participate in recreational
activities like hunting and canoeing. By 2011, however, Joas
began to feel pain in his new knee. An x-ray and bone scan
revealed aseptic loosening of the tibial component of the
implant. Translation: the bond between the implant and the
shinbone had weakened. He had revision surgery in October
2012.




1 The first case resulted in a jury verdict for Zimmer. See Batty v. Zimmer
Inc., No. 12-cv-6279, 2015 WL 11142538 (N.D. Ill. Nov. 6, 2015).
No. 16-3957                                                                 3

    In 2013 Joas sued Zimmer alleging that the NexGen Flex
design causes premature loosening for total-knee-
replacement patients who engage in activities that require a
high degree of knee flexibility. He filed his suit in federal
court in New Jersey and raised product-liability claims
premised on allegations of defective design, manufacture,
and warning. 2 (He also alleged misrepresentation and
statutory consumer-protection claims, but he abandoned
them at summary judgment.) The New Jersey court trans-
ferred the case to a multidistrict proceeding then underway
in the Northern District of Illinois addressing lawsuits
against Zimmer based on its NexGen Flex implant.
    The judge designated Joas’s case as a bellwether and
scheduled a trial. In the meantime Zimmer moved for
summary judgment on all claims. Among other things, the
manufacturer sought to exclude the testimony of Dr. Joseph
Fetto, Joas’s expert witness. Dr. Fetto’s report indicated that
his opinion testimony would be based on a differential
etiology methodology, which entailed identifying and ruling
out potential causes of the tibial loosening to arrive at the
likeliest cause of Joas’s injury. Applying Rule 702 of the
Federal Rules of Civil Procedure and Daubert v. Merrell Dow
Pharmaceuticals, Inc., 509 U.S. 579 (1993), the judge excluded
Dr. Fetto’s testimony as unreliable because he did not have
any discernible basis for determining which potential causes
of the loosening were reasonable and which were not.




2 Joas’s wife is also a plaintiff, but her claims are entirely derivative. The
New Jersey venue choice was curious. Joas and his wife are citizens of
Wisconsin; the surgery was performed there; and Zimmer is a Delaware
corporation with its principal place of business in Indiana.
4                                                 No. 16-3957

    Dr. Fetto was Joas’s only expert who would testify that a
defect in the knee implant caused his injury. With his ex-
pert’s testimony excluded, Joas could not prevail on his
claims based on defective design or manufacture. The exclu-
sion of Dr. Fetto’s testimony also left a causation gap in
Joas’s claim based on inadequate warning. To the extent that
this claim could survive without Dr. Fetto’s testimony, the
judge rejected it as deficient in other respects and entered
summary judgment for Zimmer on all claims.
                       II. Discussion
   Joas limits his appeal to his claim based on defective
warning. The claim rests on two theories. Joas argues that
Zimmer (1) failed to issue proper warnings directly to him as
the recipient of the knee replacement; and (2) failed to issue
proper warnings to his surgeon, who implanted the device.
    Importantly, Joas does not quarrel with the exclusion of
Dr. Fetto’s testimony. Rather, he urges us to allow this claim
to go forward based on the testimony of Dr. John Dearborn,
Zimmer’s expert witness. Dr. Dearborn testified in deposi-
tion that he would have used two bags of cement to properly
bond a knee implant to the patient’s shinbone. Joas’s sur-
geon, Dr. Bryan Larson, used only one bag of cement, con-
sistent with his normal practice. Joas maintains that Zimmer
had a duty to warn that two bags of cement are needed to
achieve a proper bond.
   The judge disallowed the claim for two reasons. First, she
applied the learned-intermediary doctrine, which (as rele-
vant here) holds that the manufacturer of a medical device
has no duty to warn the patient as long as the manufacturer
provides adequate warnings to the physician. Second, the
judge held that even if Zimmer had a duty to warn the
No. 16-3957                                                 5

surgeon, Joas has no evidence of causation because
Dr. Larson testified in deposition that he did not read the
packaging material Zimmer sent with the NexGen Flex
implant. Rather, he testified that he based his surgical tech-
nique entirely on his general medical training and his surgi-
cal fellowship. So an improved warning, the judge held,
would not have made any difference.
   To overcome this factual deficit, Joas asked the judge to
recognize and apply a legal presumption that the surgeon
would have heeded an improved warning had Zimmer
provided one. The judge declined to do so, holding that the
proposed “heeding presumption” has no support in
Wisconsin law.
    Both aspects of the failure-to-warn claim raise novel
questions under Wisconsin law. We turn first to Joas’s claim
that Zimmer breached a duty to directly warn him. That
inquiry requires us to predict whether the Wisconsin
Supreme Court would recognize the learned-intermediary
doctrine for use in defective-warning cases involving medi-
cal devices. We then turn our attention to Joas’s argument
that Zimmer failed to adequately warn the surgeon.
A. Alleged Failure to Warn the Patient
    We begin with the learned-intermediary doctrine, which
if applicable defeats Joas’s claim that Zimmer had a duty to
directly warn him. The doctrine holds that the manufacturer
of a prescription drug or medical device fulfills its duty to
warn of the product’s risks by informing the prescribing
physician of those risks. Neither the Wisconsin Supreme
Court nor the state’s intermediate appellate courts have
addressed the doctrine.
6                                                 No. 16-3957

    “When interpreting state law, a federal court’s task is to
determine how the state’s highest court would rule.” Rodas
v. Seidlin, 656 F.3d 610, 626 (7th Cir. 2011). If the state’s
supreme court has not yet addressed the issue, the federal
court should “consult and follow the decisions of intermedi-
ate appellate courts” to predict how the supreme court
would act given the chance, unless “there is a convincing
reason to predict the state’s highest court would disagree.”
ADT Sec. Servs., Inc. v. Lisle-Woodridge Fire Prot. Dist.,
672 F.3d 492, 498 (7th Cir. 2012). And absent “any authority
from the relevant state courts, [the federal court] … shall
examine the reasoning of courts in other jurisdictions ad-
dressing the same issue and applying their own law for
whatever guidance about the probable direction of state law
they may provide.” Pisciotta v. Old Nat’l Bancorp, 499 F.3d
629, 635 (7th Cir. 2007).
    As we’ve noted, no Wisconsin appellate court has yet
addressed this topic. As best we can tell, just one Wisconsin
trial-court decision addresses the learned-intermediary
doctrine. In Straub v. Berg, the judge applied the doctrine,
noting that “courts of numerous other jurisdictions almost
universally hold that in the case of prescription drugs, a
manufacturer’s provision of proper warnings to a prescrib-
ing physician will satisfy the manufacturer’s duty to warn
since the patient cannot obtain the drug except through the
physician.” No. 00-cv-0117, 2003 WL 26468454, at *6 (Wis.
Cir. Ct. Jan. 6, 2003).
   A few federal district courts applying Wisconsin law
have also invoked the learned-intermediary doctrine. See
Menges v. Depuy Motech, Inc., 61 F. Supp. 2d 817, 830 (N.D.
Ind. 1999) (holding that since the medical device at issue is
“available only upon prescription of a duly licensed physi-
No. 16-3957                                                   7

cian, the warning required is not to the general public or to
the patient, but to the prescribing doctor”) (quotation marks
omitted); Monson v. Acromed Corp., No. 96-C-1336, 1999 WL
1133273, at *20 (E.D. Wis. May 12, 1999) (holding in a
medical-devices failure-to-warn case that the manufacturer’s
duty to warn ran only to the treating doctor because he “is in
the best position to understand the patient’s needs and
assess the risks and benefits of a particular course of treat-
ment”) (quotation marks omitted); Lukaszewicz v. Ortho
Pharm. Corp., 510 F. Supp. 961, 963 (E.D. Wis. 1981) (noting
that “the provision of proper warnings to a physician will
satisfy the manufacturer’s duty to warn since the patient
cannot obtain the drug except through the physician”).
    One district judge has said in passing that “Wisconsin
does not apply the learned intermediary doctrine.” Maynard
v. Abbott Labs., No. 12-C-0939, 2013 WL 695817 (E.D. Wis.
Feb. 26, 2013). That statement is incorrect—the Wisconsin
Supreme Court has never weighed in on the topic. Maynard
itself is bereft of any analysis on the point.
    The doctrine enjoys broad support in other jurisdictions.
As the Texas Supreme Court has recently explained, “[t]he
highest courts of at least thirty-five states have adopted
some form of the learned intermediary doctrine within the
prescription drug products-liability context or cited favora-
bly to its application within this context.” Centocor, Inc. v.
Hamilton, 372 S.W.3d 140, 158 n.17 (Tex. 2012) (collecting
cases). And the intermediate appellate courts in another
13 states have applied the learned-intermediary doctrine or
have predicted that their supreme courts would do so. See
Tyree v. Boston Sci. Corp., 56 F. Supp. 3d 826, 828 n.3 (S.D. W.
Va. 2014) (confirming Centocor’s count and collecting other
appellate-court decisions).
8                                                        No. 16-3957

    The justification for adopting the learned-intermediary
doctrine in cases involving prescription drugs applies even
more forcefully in cases involving surgical implants. As one
district judge has explained, patients “could conceivably
gain access to prescription drugs without their doctor’s
assistance, [but] it is not reasonably conceivable that an
individual could obtain and implant a device that requires a
trained surgeon without the intervention of a physician.”
Beale v. Biomet, Inc., 492 F. Supp. 2d 1360, 1368 (S.D. Fla.
2007).
    In short, there is good reason to think that given the op-
portunity, the Wisconsin Supreme Court would join the vast
majority of state supreme courts and adopt the learned-
intermediary doctrine for use in defective-warning cases like
this one involving a surgical implant. We predict that the
state high court would do so. Accordingly, to the extent that
Joas’s defective-warning claim is based on Zimmer’s duty to
warn him, it is foreclosed by the learned-intermediary doc-
trine.
   That point aside, summary judgment for Zimmer was
proper on this aspect of the claim for a number of additional
reasons. To start, although as a general matter a manufactur-
er owes a duty to warn consumers of dangers associated
with the proper use of its product, Joas has not identified
any danger that Zimmer should have warned him about.
Strasser v. Transtech Mobile Fleet Serv., Inc., 613 N.W.2d 142,
154 (Wis. 2000). He claims in his brief that he thought the
implant would last at least 20 years based on some Zimmer
marketing materials he read. 3 But as we’ve noted, he aban-


3The marketing material Joas points to is a pamphlet provided to him by
his doctor that he assumed “was probably from Zimmer” but which the
No. 16-3957                                                           9

doned his misrepresentation and consumer-protection
claims on summary judgment. He cannot resurrect them on
appeal by repackaging them as a new iteration of his defec-
tive-warning claim.
    Summary judgment for Zimmer was also proper on this
claim because Joas has no evidence to support causation. “A
plaintiff who has established both a duty and a failure to
warn must also establish causation by showing that, if
properly warned, he or she would have altered behavior and
avoided injury.” Kurer v. Parke, Davis & Co., 679 N.W.2d 867,
876 (Wis. Ct. App. 2004). Joas argues that if Zimmer had
warned him of a risk of early failure, he would have “heed-
ed the warning and been inclined to choose an implant with
a known greater longevity.”
   But Joas didn’t select the NexGen Flex implant.
Dr. Larson did, and he made his decision based on his own
past experience, not on any marketing materials or infor-
mation provided by Zimmer.
        Q. In the case of Mr. Joas, is it true that you
           chose the products that you thought would
           best treat his medical condition?
        A. Yes.
        Q. And, again, what did you base your selec-
           tion of the LPS-Flex and the stemmed tibial
           component for Mr. Joas on?




doctor testified was not actually produced by Zimmer but, rather, by the
“general academy source down in Eau Claire.”
10                                                         No. 16-3957

        A. On my experience with it and what it’s pro-
           vided for patients that I’ve done previous to
           that particular individual.
    Moreover, Joas has not identified another implant that is
known to have greater longevity that he would have select-
ed if he had made the choice himself. “Even in the event that
a warning is inadequate, proximate cause is not presumed.”
Id. “Absent proof that a more complete or explicit warning
would have prevented” his acceptance of the NexGen Flex
implant, Joas “cannot establish that [Zimmer’s] alleged
failure to warn was the proximate cause of [his] injuries.” Id.
Indeed, Joas testified in deposition that even if he had been
warned that a certain percentage of these implants might
loosen or fail, he still would have gone through with the
surgery. The judge was right to award summary judgment
to Zimmer on this aspect of Joas’s defective-warning claim.
B. Alleged Failure to Warn the Surgeon
   Joas also claims that Zimmer failed to issue an adequate
warning to his surgeon about the amount of cement needed
to properly bond the knee implant. This theory is based
entirely on Dr. Dearborn’s testimony that he would have
used two cement bags during the surgery instead of just one,
as Dr. Larson did. 4
    That’s not enough to support a defective-warning claim
in this context. No evidence supports Joas’s contention that
it was Zimmer’s responsibility to instruct surgeons about the
amount of cement they should use in implant surgery. In


4 As noted above, Dr. Dearborn was Zimmer’s expert witness. Joas’s own
expert witness testified that there was nothing deficient in the surgeon’s
technique.
No. 16-3957                                                11

fact, all the record evidence is to the contrary. Dr. Dearborn
explained in his expert report that “surgeons are primarily
guided in their [implant] technique by the basic medical
training received during residency and/or fellowship train-
ing.” Dr. Larson confirmed as much in his own deposition:
      Q. The technique that you used to implant [the
         NexGen Flex] products in Mr. Joas in 2008,
         how’d you learn that technique?
      A. From my fellowship training and residency.
      Q. And with respect to how to position the
         components or cement the components,
         how did you learn that?
      A. Again, from the residency and my fellow-
         ship training.
      Q. Is there any printed material or written ma-
         terial from Zimmer that you relied upon in
         knowing how to position or implant
         Mr. Joas’s products?
      A. No, there is not.
      Q. Were you relying exclusively on training
         and education during your residency and
         fellowship?
      A. That’s correct.
    In addition, in his expert report, Dr. Dearborn explained
that the warnings and instructions Zimmer included with its
implant were “reasonable and adequately inform[ed] the
relevant healthcare providers” of the foreseeable risks.
Surgical cementing techniques and the adequacy of warn-
ings from implant manufacturers are specialized medical
12                                                No. 16-3957

issues and not “within the realm of the ordinary experience
of mankind”; expert testimony is required to support a
defective-warning claim premised on this theory. State v.
Kandutsch, 799 N.W.2d 865, 872 (Wis. 2011) (quotation marks
omitted). Joas has none.
    Beyond the lack of expert support for this theory, no evi-
dence suggests that Dr. Larson would have followed an
improved instruction on cementing techniques had Zimmer
provided one. Joas argued at the summary-judgment hear-
ing that the judge should allow this claim to go forward
based on a “heeding presumption,” which permits the
factfinder to presume, in the absence of proof, that a proper
warning would have been read and heeded. Here again, the
state appellate courts have not addressed this doctrine. We
seriously doubt that they would adopt it in this context.
    To the contrary, as we’ve already noted, the state court of
appeals has recently held that “[a] plaintiff who has estab-
lished both a duty and a failure to warn must also establish
causation by showing that, if properly warned, he or she
would have altered behavior and avoided injury.” Kurer,
679 N.W.2d at 876. The plaintiff in that case failed to show
that the relevant actor “would have heeded a different
warning,” so the court upheld a summary judgment for the
defendant. Id. at 880.
    Joas relies on Tanner v. Shoupe, an earlier failure-to-warn
case about an exploding car battery. 596 N.W.2d 805 (Wis.
Ct. App. 1999). There the defendant argued that additional
warnings would have been useless because Tanner, the
plaintiff, testified that he did not read any warnings on the
battery. But the case turned on whether an improved warn-
ing would have been read and heeded by an earlier user. The
court determined that “[i]f the battery had contained a
No. 16-3957                                                  13

warning against pounding on the vent caps, a fact-finder
could ‘reasonably assume that it [would have been] read and
heeded’ by the users prior to Tanner.” Id. at 818 (emphasis
added) (quoting RESTATEMENT (SECOND) OF TORTS § 492A
cmt. j (AM. LAW INST. 1965)).
     By its own terms, then, Tanner does not apply to an actor
who has “admitted he did not read the warnings” himself.
Id.; see also Forst v. SmithKline Beecham Corp., 602 F. Supp. 2d
960, 970 & n.4 (E.D. Wis. 2009) (applying Kurer instead of
Tanner in a case involving prescription-drug warnings
because of its “analogous facts”). Kurer, not Tanner, controls
here.
    Dr. Larson testified that he did not read the instructions
that accompanied the knee implant. So even if Joas could
establish that Zimmer breached a duty to warn the surgeon,
summary judgment was appropriate because no evidence
shows that “if properly warned, [Dr. Larson] would have
altered [his] behavior and avoided injury.” Kurer,
679 N.W.2d at 876.
    As a fallback position, Joas asks us to certify the ques-
tions of the learned-intermediary doctrine and the heeding
presumption to the Wisconsin Supreme Court. We have no
need to take that step. Certification is appropriate if we are
“genuinely uncertain about a question of state law that is
vital to a correct disposition of the case.” Cleary v. Philip
Morris Inc., 656 F.3d 511, 520 (7th Cir. 2011) (quotation marks
omitted). No genuine uncertainty exists here.
                                                     AFFIRMED.
