Court Opinion

ID: 6344457
Source: CourtListenerOpinion
Date Created: 2022-05-26 20:02:01.775367+00
Date Added: 2024-06-11T08:50:21.991504
License: Public Domain

Filed 5/26/22
                CERTIFIED FOR PUBLICATION

IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA

                 SECOND APPELLATE DISTRICT

                        DIVISION EIGHT

GARY KLINE,
       Plaintiff and Respondent,             B302544
       v.
                                             (Los Angeles County
ZIMMER, INC.,                                Super. Ct. No. BC444834)
       Defendant and Appellant.

      APPEAL from a judgment of the Superior Court of Los
Angeles County. Daniel J. Buckley, Judge. Reversed and
remanded.
      Faegre Drinker Biddle & Reath, Tarifa B. Laddon, Amanda
Semaan, Bruce Jones and Joseph M. Price for Defendant and
Appellant.
      Waters Kraus & Paul, Gary M. Paul and Michael B. Gurien
for Plaintiff and Respondent.

                ___________________________________
       This is an appeal of a judgment entered after a limited
retrial of plaintiff and respondent Gary Kline’s personal injury
claims against defendant and appellant Zimmer, Inc. (Zimmer), a
medical device manufacturer. Zimmer asserts that the trial court
made two categories of evidentiary error and that the jury
awarded Kline excessive damages. We agree with Zimmer that
the court erred in categorically excluding all of Zimmer’s
proffered medical opinions expressed to less than a reasonable
medical probability as to issues on which Kline bore the burden of
proof. Because that error prevented Zimmer from presenting any
expert testimony as to an issue where expert testimony was
essential, we reverse for a retrial. As Zimmer’s other points of
error are not necessary to our disposition of this appeal, we
decline to address them.
                           BACKGROUND
       Due to painful osteoarthritis in his right hip, Kline
underwent a total hip replacement surgery in 2007, during which
he was implanted with an artificial joint called the Durom
Acetabular Component (Durom Cup). Zimmer was the
manufacturer of the Durom Cup. The initial surgery failed and
Kline underwent a second surgery—known as a “revision
surgery”—in September 2008 to replace the Durom Cup with a
different device. Kline continued to experience severe pain after
his revision surgery. He underwent various treatments and
physical therapy, and, by March of 2009, he was “back to normal”
and “feeling pretty good.” With this progress, Kline was released
from the care of his physical therapist and his orthopedic
surgeon.

                                2
       However, the pain returned and Kline began seeing a
rheumatologist, Dr. Chabra, in September of 2010. Kline
continued to see Dr. Chabra for approximately eight years.
Dr. Chabra noted at his initial visit that Kline was complaining
of hip pain and stiffness in both hips, with stiffness primarily in
his surgically repaired hip. Kline also complained of lower back
pain. Dr. Chabra performed a series of tests and studies and did
not reach a conclusion as to the cause of his pain. Dr. Chabra did
prescribe Kline a steroid, together with other drugs, to see if it
would alleviate his symptoms. The steroid did so but, in
consultation with Dr. Chabra, Kline discontinued its use over
concerns of negative side effects. Kline’s condition then
deteriorated significantly. Thereafter, he repeatedly went back
on, and then back off, the steroid with corresponding
improvements and set-backs in his pain levels. Dr. Chabra also
prescribed Kline narcotic pain medication and physical therapy,
but the pain and limitations on mobility persisted, particularly in
the right hip area.
       At some point Kline made the decision to sue Zimmer.
The thrust of his claim was that the Durom cup was defective;
were it not defective his first surgery likely would have
substantially resolved his hip issues; because it was defective he
suffered ongoing pain and impairments and required a second
surgery; and the second surgery left him with permanent pain
and impairments. In 2015, a jury found the Durom Cup was, in
fact, defective and awarded Kline $153,317 in economic damages
and $9 million in non-economic damages. But the first trial court
granted a new trial based on its view of the damages being
excessive and misconduct on the part of Kline’s counsel. On an
appeal and cross-appeal raising a multitude of issues, we

                                 3
affirmed that grant in part and “remanded to the trial court for a
retrial on Kline’s damages caused by the design defect of the
Durom Cup.” (Kline v. Zimmer, Inc. (Apr. 27, 2018, B269317)
                            1
[nonpub. opn] (Zimmer I).).
       The second trial proceeded in 2019 and Kline was still
experiencing pain and weakness, with attendant limitations on
his daily life and activities. The jury in the second trial heard
testimony from, among others, Kline, Dr. Chabra, Kline’s
orthopedic surgeon, Kline’s current treating physician, and an
expert hired by Kline to testify to the cause of his pain and other
limitations. Kline’s expert testified to a reasonable medical
probability that his pain and weakness were a result of a defect
in the Durom Cup that caused pain, inflammation, and changes
to his hip joint which necessitated a second surgery, and that the
second surgery resulted in changes to Kline’s muscles and soft
tissues causing him chronic pain. Prior to the first surgery, he
opined, Kline had a “good high percentage potential of

1      Zimmer has moved to augment the record with this
unpublished opinion and the parties’ related briefing pursuant to
California Rules of Court, rule 8.155(a)(1). California Rules of
Court, rule 8.155(a)(1), applies only to “superior court”
documents; not documents filed in a prior appeal. We therefore
treat Zimmer’s motion as a request for judicial notice and grant it
only with respect to our unpublished opinion pursuant to
Evidence Code 452, subdivision (d). (See, e.g., Estate of Dito
(2011) 198 Cal.App.4th 791, 795, fn. 3 [taking judicial notice, on
its own motion, of unpublished opinion in prior appeal in same
matter].) We are unpersuaded of the necessity of reviewing briefs
filed in the prior appeal in this instance for “background and
history,” which the parties ably provided in their briefs in this
appeal. We therefore deny Zimmer’s motion as to those
documents.

                                 4
treatment,” but because that surgery was rendered unsuccessful
by the defective Durom Cup, Kline no longer has “a good high
percentage treatment available.”
       The jury did not hear from an expert for Zimmer. Although
Zimmer offered an expert, Dr. Sah, who was prepared to testify
about “possible” alternative causes of Kline’s pain, the trial court
excluded any and all medical opinions that were expressed to less
than a reasonable medical probability. Because Dr. Sah was
unable to offer an opinion to a reasonable medical probability,
Zimmer had no expert testimony. The court also excluded certain
testimony from Kline’s treating physicians relating to potential
alternative causes of his pain on the same basis.
       The second trial resulted in a slightly smaller jury verdict
against Zimmer: $80,460.19 in economic damages and
$7.6 million in noneconomic damages. Zimmer moved for another
retrial based on (1) the exclusion of testimony on the grounds it
was offered to less than a reasonable medical probability, (2) the
exclusion of certain photographs and a video showing Kline
engaged in hunting and shooting activities; and (3) excessive
damages. The trial court denied Zimmer’s motion. Zimmer now
appeals the judgment and denial of its motion for retrial on the
same grounds for which it sought retrial. We reverse the
judgment and remand for retrial because we agree with Zimmer
on its first point of error.
                             DISCUSSION
       Zimmer contends that the trial court erred by excluding
expert medical opinions Zimmer proffered because such opinions
were not stated to a reasonable medical probability. The court’s
basis for exclusion was purely legal: it interpreted California law
as barring any expert opinion stated to less than a reasonable

                                 5
probability, rendering one identifying a mere “possible
cause . . . not a proper opinion . . . .”
       Although we ordinarily review rulings excluding expert
testimony for abuse of discretion, our review is de novo when
such rulings are based on a conclusion of law. (Sargon
Enterprises, Inc. v. University of Southern California (2012) 55
Cal.4th 747, 773 (Sargon).)
           1. Purpose for Which the Opinions Were Offered
       Under California law, causation “in a personal injury
action . . . must be proven within a reasonable medical
probability based upon competent expert testimony.” (Jones v.
Ortho Pharmaceutical Corp. (1985) 163 Cal.App.3d 396, 402
(Ortho Pharmaceutical).) The reasonable medical probability
standard mirrors the more-likely-than-not standard of proof in
general negligence actions. (Id. at p. 403.) Kline and Zimmer
agree that expert causation testimony expressed short of a
reasonable medical probability is inadmissible when offered by
the party with the burden of proof. Zimmer contends, however,
that the same rule does not apply to a party without the burden
of proof, specifically when a defendant’s expert testimony is
offered only to challenge the plaintiff’s expert’s causation
opinions. This contention prompted a disagreement between the
parties concerning the purpose for which Zimmer offered the
excluded expert causation opinions.
       According to Kline, Zimmer “was attempting to establish
alternative causes of Mr. Kline’s injuries . . . for the purpose of
reducing the noneconomic damages for which it was liable in the
damages-only trial.” (Italics added.) As to Dr. Sah specifically,
Kline claims the purpose of Dr. Sah’s proposed testimony was
“to identify and prove actual alternative causes [of Kline’s

                                 6
injury] . . . .” (Italics added.) Zimmer, on the other hand, argues
it “offered the testimony of its expert Dr. Sah and [Kline’s]
treating doctors to challenge whether Kline had met his burden of
proof on [the causation] issue.” (Italics added.) The record
supports Zimmer’s position.
       Starting with Dr. Sah, Zimmer explained in its opposition
to Kline’s motion to exclude Dr. Sah’s testimony that the purpose
of such testimony was to “challeng[e] [Kline’s] expert’s opinion
regarding causation . . . .” Zimmer’s offer of proof made in
support of that opposition, and which incorporated that
opposition by reference, was that Dr. Sah would offer “alternative
causes [as] possible explanations for [Kline’s] pain,” i.e.,
explanations different than those offered by Kline’s expert.
When pressed by the trial court on use of the term “possible,”
Zimmer confirmed it was intentional: “Yes, your Honor. Possible
alternative causes that do not rise to the greater than 50 percent
chance of causing [Kline’s] hip pain.” By acknowledging that its
evidence would not meet the standard for proving causation,
Zimmer made clear that it was not seeking to prove an
alternative cause; rather, it sought only to show Kline had failed
to carry its burden on causation. Zimmer drove this point home
later in the same colloquy: “[The] reasonable degree of medical
probability is plaintiff’s burden . . . . [T]o have a defendant state
affirmatively that one cause rises to the level of reasonable
degree of medical probability is improper burden shifting upon
the defendant.” From Zimmer’s opposition papers, its offer of
proof, and related colloquy, Zimmer adequately articulated the
purpose for which it intended to offer Dr. Sah’s testimony.
(Evid. Code, § 354, subd. (a) [purpose may be established by offer
of proof or “any other means”].)

                                 7
       The same is true of Zimmer’s proposed use of excluded
testimony from Kline’s treating physicians. For example,
Zimmer sought to introduce testimony from Kline’s treating
physicians that would demonstrate uncertainty as to the cause of
Kline’s pain by acknowledging the possibility of other causes.
Zimmer argued their testimony was admissible to cast doubt on
the conclusion of Kline’s expert: “It’s the burden of proof. If the
[treating] doctors all say [‘]we can’t say one way or the other,[’]
the plaintiffs have not met their burden of proof.” While this of
course overstates the legal effect of the proffered evidence, it
nevertheless makes clear how Zimmer proposed to use it and
what it hoped to accomplish in doing so.
         2. The Trial Court Erred in Excluding Opinions
             Offered to Challenge Kline’s Expert’s
             Conclusions on the Basis That They Were Not
             Stated to a Reasonable Medical Certainty
       Having established that Zimmer sought to introduce
causation opinions and other evidence to challenge the causation
opinion of Kline’s expert, rather than to prove an actual
alternative cause, we next consider whether the trial court erred
in excluding Zimmer’s evidence for this purpose. We find that it
did.
       The plaintiff in a personal injury action bears the burden to
prove that the defendant’s negligence was the legal cause of his
injury. (Espinosa v. Little Co. of Mary Hospital (1995) 31
Cal.App.4th 1304, 1314 (Espinosa); see also Evid. Code, § 500.)
                                               2
This means that he must ultimately persuade the factfinder that

2     The terms burden of proof and burden of persuasion are
synonymous in California. (Sargent Fletcher, Inc. v. Able Corp.
(2003) 110 Cal.App.4th 1658, 1667 (Sargent).) We use the term

                                 8
the defendant’s negligence was more likely than not a substantial
factor in causing him damages. (Espinosa, supra, 31 Cal.App.4th
at pp. 1321–1322.)
       But before the plaintiff is even entitled to submit his claim
to a factfinder, he must make a prima facie case, meaning he
must proffer evidence sufficient to permit a finding in his favor.
(Cottle v. Superior Court (1992) 3 Cal.App.4th 1367, 1385 (Cottle);
Evid. Code, § 550, subd. (b).) Where causation is “beyond the
experience of laymen,” as it is in complex medical injury cases,
such evidence must be in the form of an expert opinion that could
be accepted by the factfinder as satisfying the plaintiff’s burden of
proof. (See Ortho Pharmaceutical, supra, 163 Cal.App.3d at
pp. 402–403.) That opinion must be expressed “to a reasonable
medical probability,” which, again, means more likely than not
(ibid.), because more likely than not is the threshold level of
certainty necessary to prove a personal injury claim.
       Thus, testimony by a plaintiff’s expert who cannot opine to
a reasonable medical probability is properly excluded because the
opinion could not sustain a finding in the plaintiff’s favor.
(Cottle, supra, 3 Cal.App.4th at p. 1385 [absent evidence to show
causation to a reasonable medical probability there is no factual
question for a jury to resolve].) The reason for this is clear.
To allow a jury to consider a claim where the plaintiff’s prima
facie showing falls short of reasonable medical probability would
be to allow the jury to find the requisite degree of certainty where
science cannot: “ ‘If the experts cannot predict probability in
these situations, it is difficult to see how courts can expect a jury

persuasion here to make clear that proof refers to persuasion and
not merely production. Other references to “persuasion” herein
mean “proof” and vice versa.

                                 9
of laymen to be able to do so.’ ” (Ortho Pharmaceutical, supra,
163 Cal.App.3d at p. 403 [quoting Parker v. Employers Mut.
Liability Ins. Co. (Tex. 1969) 440 S.W.2d 43, 49].)
       The same does not apply to a defendant’s efforts to
challenge or undermine the plaintiff’s prima facie case. Even
after the plaintiff has made its prima facie case, the general rule
is that the burden to prove causation remains with the plaintiff.
(See Sargent, supra, 110 Cal.App.4th at p. 1668.) And, regardless
of whether the defendant produces any evidence at all, it remains
for the factfinder to say whether the plaintiff has in fact met its
burden to the requisite degree of certainty. (Ibid.; see also Cottle,
supra, 3 Cal.App.4th at p. 1385.)
       These general rules apply here. Kline acknowledges that
he bore the burden of proving that Zimmer caused his injuries to
a reasonable medical probability. Zimmer was entitled to put on
a case that Kline failed to satisfy that burden. To accomplish
this, Zimmer did not need to show it was more likely than not
that a cause identified by Zimmer resulted in Kline’s injuries.
In other words, Zimmer did not need to show that a different
cause was more likely than not the cause of Kline’s injuries.3

3      This is true only because Zimmer was not attempting to
affirmatively prove that there was, in fact, a different cause of
Kline’s pain, such as for the purpose of allocating damages to a
third party. Kline cites authorities where the defendant, having
undertaken such an effort, was required to show causation to a
reasonable medical probability. (See Sparks v. Owens-Illinois,
Inc. (1995) 32 Cal.App.4th 461, 478 [defendant seeking to allocate
liability to third parties bears burden to show such third parties
are legal causes and percentage of fault]; Stewart v. Union
Carbide Corp. (2010) 190 Cal.App.4th 23, 33 [same], disapproved
on another ground in Webb v. Special Electric Co., Inc. (2016) 63

                                 10
All that Zimmer needed to show was that Kline’s evidence was
insufficient to prove Kline’s injuries were more likely than not
caused by Zimmer. It should have been permitted to do so by
offering expert opinions offered to less than a reasonable medical
probability that Kline’s injuries may have been attributable to
other causes. (Cf. Cahill Bros., Inc. v. Clementina Co. (1962) 208
Cal.App.2d 367, 385 [defendant without burden of proof needed
only to “produce evidence sufficient to offset the effect of . . .
plaintiff’s showing; it was not required to offset it by a
preponderance of the evidence”].) Such defense expert opinions
could cast doubt on the accuracy and reliability of a plaintiff’s
expert. The jury is entitled to consider such evidence in deciding
whether the plaintiff’s expert is exaggerating his or her opinion.4
      In so holding, we join state and federal courts from across
the country that recognize the reasonable medical probability
requirement applies only to the party bearing the burden of proof

Cal.4th 167, 188.) We have no disagreement with these
authorities as far as they go. (See also Espinosa, supra, 31
Cal.App.4th at p. 1321 [“A plaintiff does not have the burden of
apportioning damages”].) However, they do not concern the
scenario presented here: a defendant with no burden to prove any
matter seeking to introduce evidence for the purposes of
demonstrating only that the plaintiff failed to meet its burden.

4     For example, if the plaintiff’s expert opines there is a 99
percent certainty that defendant caused an injury, and the
defense expert opines that he cannot say with certainty who
caused the injury, but there is a 49 percent certainty that it was
someone other than defendant, the jury should have the
opportunity to consider the defense opinion in deciding whether
plaintiff’s expert is exaggerating and cannot be trusted.

                                11
                                               5
on the issue which is the subject of the opinion. We are
particularly persuaded by the reasoning of the United States
Court of Appeal for the First Circuit in Wilder v. Eberhart (1st
Cir. 1992) 977 F.2d 673, 677 (Wilder). Applying New Hampshire
medical malpractice law, the Wilder court concluded that
“inequities would abound” if a defendant could not rebut the
plaintiff’s prima facie case without actually proving an
alternative cause:
      “For example, if ninety-nine out of one hundred medical
experts agreed that there were four equally possible causes of a
certain injury, A, B, C and D, and plaintiff produces the one

5      (E.g., R.J. Reynolds Tobacco Co. v. Mack (Fla.Dist.Ct.App.
2012) 92 So.3d 244, 248 [“[b]y excluding [defendant’s] alternative
causation evidence on the basis that its experts could not testify
to a reasonable degree of medical probability, the trial court
improperly shifted the burden of proof as to causation to
[defendant]”]; Williams v. Eighth Judicial Dist. Court of Nev.
(Nev. 2011) 262 P.3d 360, 362-363 [“when a defense expert’s
testimony of alternative causation theories controverts an
element of the plaintiff’s prima facie case where the plaintiff
bears the burden of proof, the testimony need not be stated to a
reasonable degree of medical probability”]; Roy v. St. Lukes
Medical Center (Wis.Ct.App. 2007) 741 N.W.2d 256, 264
[“ ‘Although the party with the burden of proof must produce
testimony based upon reasonable medical probabilities, the
opposing party is not restricted to this requirement and may
attempt to weaken the claim for injuries with medical proof
couched in terms of possibilities.’ [Citation].”]; Sakler v.
Anesthesiology Assocs. P.S.C. (Ky.Ct.App. 2001) 50 S.W.3d 210,
214 [“expert testimony [offered to less than a reasonable
probability] is admissible on behalf of defendants in medical
malpractice cases in order to rebut the testimony of plaintiffs
upon whom the burden of proof rests”].)

                                12
expert who conclusively states that A was the certain cause of his
injury, defendant would be precluded from presenting the
testimony of any of the other ninety-nine experts, unless they
would testify conclusively that B, C, or D was the cause of injury.
Even if all of defendant’s experts were prepared to testify that
any of the possible causes A, B, C or D, could have equally caused
plaintiff’s injury, so long as none would be prepared to state that
one particular cause, other than that professed by plaintiff more
probably than not caused plaintiff’s injury, then defendant’s
experts would not be able to testify at all as to causation. . . .
[This] would be manifestly unjust and unduly burdensome on
defendants.” (Wilder, supra, 977 F.2d at p. 677.)
       Complex questions of medical causation are prone to
uncertainty. (See, e.g., Ortho Pharmaceutical, supra, 163
Cal.App.3d at p. 403.) As Wilder illustrates, to allow testimony
from a sincere but overconfident expert, but not from an equally
sincere expert harboring reasonable doubts, risks closing the
courtroom door to scientific consensus (or the absence thereof).
It is therefore imperative that the party without the burden of
proof be allowed to suggest alternative causes, or the uncertainty
of causation,6 to less than a reasonable medical probability.

6      We note that the trial court advised Zimmer that, if its
expert could “state with a reasonable degree of medical certainty
that no doctor can say that a cause exist[s] here[,] that is
admissible.” This does not solve the problem. First, it still
imposes on the defendant the burden of proof on causation
because it requires the defendant to show that something is more
likely than not. Second, it asks the impossible of a rebuttal
expert who, by definition, is responding to the testimony of an
expert who has said exactly what the trial court would require
the rebuttal expert to testify no doctor could say.

                                13
To withhold such information from the jury is to deprive it of
relevant information in assessing whether the plaintiff has met
its ultimate burden of persuasion. And, it would improperly
transfer from the jury to the court the responsibility for resolving
conflicts between competing expert opinions. (See Sargon, supra,
55 Cal.4th at p. 772 [not the role of court to resolve scientific
controversies]; Davis v. Honeywell Internat. Inc. (2016) 245
Cal.App.4th 477, 480 [“it is for the jury to resolve the conflict
between . . . any competing expert opinions”]; see also CACI 221
[role of jury to resolve disagreements between experts].)
       This is not to say that a trial court must accept every
opinion offered by a defense expert, no matter how speculative.
To the contrary, an “ ‘expert’s opinion may not be based “on
assumptions of fact without evidentiary support [citation], or on
speculative or conjectural factors . . . .” ’ ” (Sargon, supra, 55
Cal.4th at p. 770.)7 But, Kline’s arguments notwithstanding, just

7      Here, for example, the trial court conditionally excluded
testimony that a Vitamin D deficiency could cause pain of the
nature Kline was experiencing where there was insufficient
evidentiary support for the conclusion that Kline actually had a
Vitamin D deficiency and the record evidence indicated he, in
fact, did not have any such deficiency. This was a proper exercise
of the court’s gatekeeping role under Evidence Code section 801,
subdivision (b). (Jennings v. Palomar Pomerado Health Systems,
Inc. (2003) 114 Cal.App.4th 1108, 1117 [“an expert’s opinion that
something could be true if certain assumed facts are true,
without any foundation for concluding those assumed facts exist
in the case before the jury, does not provide assistance to the jury
because the jury is charged with determining what occurred in
the case before it, not hypothetical possibilities”] (italics added).)
In contrast, where the evidence showed, for example, that Kline

                                 14
because an opinion does not reach the reasonable medical
probability threshold does not render it speculative. Less than a
reasonable probability is a wide spectrum that begins at
50 percent likely and ends at impossible. (See Ortho
Pharmaceutical, supra, 163 Cal.App.3d at p. 403.) While the trial
court has discretion to determine the point at which an opinion
becomes speculative, subject to the applicable provisions of the
Evidence Code, that threshold is necessarily shy of the 50 percent
likelihood cutoff imposed on Zimmer in this case.
         3. Excluding Zimmer’s Proffered Expert
             Testimony Solely Because It Was Not Expressed
             to a Reasonable Medical Probability Requires
             Reversal Under the Circumstances
       An appellant seeking reversal based on the erroneous
exclusion of evidence ordinarily “must show that a different
result was probable if the evidence had been admitted.”
(Karlsson v. Ford Motor Co. (2006) 140 Cal.App.4th 1202, 1223.)
This rule is compelled by article VI, section 13, of the California
Constitution, section 353 of the Evidence Code, and section 475 of
the Code of Civil Procedure.
       However, the rule does not apply where the error is deemed
“structural.” Such an error typically occurs when the trial court
deprives a party of its due process right to a fair trial.
(Conservatorship of Maria B. (2013) 218 Cal.App.4th 514, 534.)
A structural error is one that “affect[s] ‘the framework within
which the trial proceeds, rather than simply an error in the trial
process itself,’ thus affecting the entire conduct of the trial from

experienced lower back pain, suffered from arthritis, and was
overweight, the trial court erred in excluding expert testimony
that these factors could have caused his pain.

                                15
beginning to end. [Citation.] Structural errors require per se
reversal ‘because it cannot be fairly determined how a trial would
have been resolved if the grave error had not occurred.’ ”
(Severson & Werson, P.C. v. Sepehry-Fard (2019) 37 Cal.App.5th
938, 950.) The effects of such an error are not susceptible to
measurement and therefore defy analysis by harmless error
standards. (Id. at p. 951.)
       One element of a fair trial is the right to offer admissible
evidence on a material issue. (Elkins v. Superior Court (2007)
41 Cal.4th 1337, 1357, superseded by statute on other grounds as
stated in In re Marriage of Swain (2018) 21 Cal.App.5th 830,
840.) Therefore, improper exclusion of expert testimony can
amount to structural error when it deprives a party of this right.
       Zimmer cites People ex rel. Depart. of Transportation v.
Clauser/Wells Partnership (2002) 95 Cal.App.4th 1066 (Clauser/
Wells) for the proposition that improper exclusion of expert
testimony may warrant reversal. Clauser/Wells was an eminent
domain action in which the sole issue was the value of the
defendant’s business inventory. The defendant and the plaintiff
(Caltrans) each proffered expert testimony on the topic.
According to Caltrans’s expert, the inventory was worth
$439,220; according to the defendant’s expert, it was worth
$2,178,390. The trial court excluded Caltrans’s expert’s opinion
entirely, leaving Caltrans with no expert testimony at trial.
The jury returned a verdict for the defendant for $2,178,390.
(Id. at pp. 1069–1070.) After concluding the court erred in
excluding Caltrans’s expert testimony, the appellate court found
prejudice per se. It explained: “ ‘It is prejudicial error to exclude
relevant and material expert evidence where a proper foundation
for it has been laid, and the proffered testimony is within the

                                 16
proper scope of expert opinion.’ ” (Clauser/Wells, supra, 95
Cal.App.4th at p. 1086.)
       Similarly, the court in Gordon v. Nissan Motor Co. Ltd.
(2009) 170 Cal.App.4th 1103 (Nissan) found reversible error per
se when the trial court erroneously excluded expert testimony
necessary to establish the plaintiff’s theory of liability. (Id. at
p. 1116.) The Nissan court stated: “when a trial court
erroneously denies all evidence relating to a claim, or essential
expert testimony without which a claim cannot be proven, the
error is reversible per se because it deprives the party offering
the evidence of a fair hearing and of the opportunity to show
actual prejudice. [Citations.]” (Id. at p. 1114.) We find that the
same is true when the trial court erroneously excludes expert
testimony which is essential to mounting a defense.
       In this case, the issue of causation was beyond experience
of laypeople. As such, it was the proper subject of expert
testimony. (Evid. Code, § 801, subd. (a).) The trial court properly
admitted Kline’s expert testimony on the subject but erroneously
excluded Zimmer’s. As a result, Zimmer was unable to offer any
expert testimony, notwithstanding that it had proffered
admissible and material testimony that the jury was entitled to
hear. This resulted in a one-sided presentation of evidence.
By its nature, unrebutted expert testimony is susceptible to being
accepted at face value.8 The result of the original trial in
Clauser/Wells illustrates this: when only one expert testified to

8     Zimmer’s counsel made this point to the trial court,
explaining that excluding its causation evidence offered to less
than a reasonable medical probability would leave Kline’s expert
the sole witness on the topic—a result akin to “directing a
verdict.”

                                17
value, the jury returned a verdict in the exact amount suggested
by that expert. (Clauser/Wells, supra, 95 Cal.App.4th at
p. 1070.) Indeed, Kline recognized the advantage of having the
only expert at trial and capitalized on it. For example, in closing
argument, Kline’s trial counsel highlighted that there was no
rebuttal to Kline’s expert’s testimony that “the only cause of
[Kline’s] problems [wa]s the surgery.” “Who came in to refute
that?” he asked. “Nobody,” he answered.
      The trial court’s categorical exclusion of Zimmer’s expert
testimony on a central issue, which was beyond the experience of
laypeople, deprived Zimmer of a fair trial and therefore
constitutes structural error. (Cf. Brown v. Colm (1974) 11 Cal.3d
639, 647 [“[T]he exclusion of the sole expert relied upon by a
party because of an erroneous view of his qualifications is, in a
case where expert testimony is essential, an abuse of discretion
as a matter of law requiring reversal”].) We therefore reverse
and remand for a new trial without considering what verdict
would probably have been returned if the defense expert’s
testimony had been admitted. (Aulisio v. Bancroft (2014) 230
Cal.App.4th 1516, 1527 [“ ‘A structural error requires reversal
without regard to the strength of the evidence or other
circumstances.’ ”].)
      As Zimmer’s other points of error are not necessary to our
disposition of this appeal, we decline to address them.

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                           DISPOSITION
       The judgment is reversed. We remand for a retrial on those
same issues we ordered retried in Zimmer I, i.e., Kline’s damages
caused by the design defect of the Durom Cup. Zimmer is
entitled to its costs on appeal.
       CERTIFIED FOR PUBLICATION

                                                         *
                                      HARUTUNIAN, J.
We concur:

             STRATTON, P. J.

             GRIMES, J.

*     Judge of the San Diego Superior Court, assigned by the
Chief Justice pursuant to article VI, section 6 of the California
Constitution.

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