FILED
                                                            United States Court of Appeals
                                                                    Tenth Circuit

                   UNITED STATES COURT OF APPEALS                 January 9, 2019

                         FOR THE TENTH CIRCUIT                 Elisabeth A. Shumaker
                       _________________________________           Clerk of Court

    KENNETH R. ZARTNER,

          Plaintiff - Appellant,

    v.                                                No. 17-1355
                                          (D.C. No. 1:15-CV-02218-PAB-KLM)
    SHAWN L. MILLER,                                   (D. Colo.)

          Defendant - Appellee.
                      _________________________________

                          ORDER AND JUDGMENT *
                       _________________________________

Before BRISCOE, BACHARACH, and CARSON, Circuit Judges.
                 _________________________________

         This appeal grew out of Officer Shawn Miller’s handcuffing of Mr.

Kenneth Zartner during an arrest. In the aftermath, Mr. Zartner sued

Officer Miller under 42 U.S.C. § 1983, claiming excessive force by making

the handcuffs too tight. 1 Officer Miller moved for summary judgment based

on qualified immunity, and the district court granted the motion.




*
      This order and judgment does not constitute binding precedent except
under the doctrines of law of the case, res judicata, and collateral estoppel.
But the order and judgment may be cited if otherwise appropriate. See Fed.
R. App. P. 32.1(a); Tenth Cir. R. 32.1(A).
1
      Mr. Zartner also sued the City and County of Denver, a jail nurse,
and six deputy sheriffs. But this appeal involves only Mr. Zartner’s § 1983
claim against Officer Miller for the allegedly tight handcuffs.
      We affirm because Mr. Zartner did not present adequate evidence of

a causal link between the allegedly tight handcuffs and an actual injury.

Without adequate evidence of a causal link, Mr. Zartner cannot prevail

against Officer Miller.

I.    Mr. Zartner was diagnosed with a fracture in his right wrist after
      two separate uses of force.

      Officer Miller arrested Mr. Zartner for aggravated theft of a motor

vehicle, handcuffing him in the process of making the arrest. Mr. Zartner

was then taken to a detention center, where he was examined by medical

staff. During the examination, no injuries were reported or observed.

      The next day, Mr. Zartner was to be fingerprinted. He refused to

cooperate, so a group of deputy sheriffs forced Mr. Zartner to give his

fingerprints, using nunchucks to apply pressure to his wrists.

      Mr. Zartner was then reexamined by a nurse. The nurse asked Mr.

Zartner whether he was hurting, but he didn’t respond and the nurse again

observed no injuries.

      Later that day, Mr. Zartner complained about wrist pain, leading to

an examination of his wrists and the taking of x-rays. From the x-rays, Dr.

David Symonds diagnosed Mr. Zartner with a fracture in his right wrist.

II.   When reviewing the grant of summary judgment, we engage in de
      novo review.

      We review de novo a district court’s grant of a motion for summary

judgment. Lamb v. Norwood, 

, 1162 (10th Cir. 2018). The

                                     2
motion must be granted if the moving party shows that (1) the parties do

not genuinely dispute any material facts and (2) the moving party is

entitled to judgment as a matter of law based on those facts. Fed. R. Civ.

P. 56(a). When applying this standard, we view the evidence in the light

most favorable to the nonmoving party and draw all reasonable inferences

in this party’s favor. Havens v. Colo. Dep’t of Corr., 

, 1259

(10th Cir. 2018).

     We must apply this standard in the context of qualified immunity,

which shields officers from civil damages if their conduct does not violate

a clearly established right. Harlow v. Fitzgerald, 

, 818 (1982);

Schwartz v. Booker, 

, 579 (10th Cir. 2012). Once an officer

asserts qualified immunity, the plaintiff must

          allege facts showing that the officer violated a constitutional
           right and

          identify case law showing that this right was clearly
           established when the officer acted.

See 

.

     In this circuit, unduly tight handcuffing can constitute excessive

force under the Fourth and Fourteenth Amendments. Cortez v. McCauley,

, 1129 (10th Cir. 2007) (en banc). To trigger liability for

unduly tight handcuffs, however, the plaintiff must show




                                      3
           an actual injury, 2

           a causal link between this injury and the unduly tight
            handcuffs, 3 and

           the officer’s knowledge that the handcuffs were too tight. 4

III.   The district court concluded that there was no constitutional
       violation based on two independent grounds.

       The district court granted summary judgment to Officer Miller based

on qualified immunity, concluding that Mr. Zartner had failed to show a

violation of his constitutional rights. This conclusion rested on two

independent grounds:

       1.   Mr. Zartner had failed to show a causal link between the
            allegedly tight handcuffs and an actual injury.

       2.   Mr. Zartner had failed to show that Officer Miller knew that
            the handcuffs were too tight.

Because the district court gave two independent rationales, Mr. Zartner can

prevail on appeal only by successfully challenging both. See Lebahn v.

Nat’l Farmers Union Unif. Pension Plan, 

, 1188 (10th Cir.

2016) (“When a district court dismisses a claim on two or more




2
      See 

& n.24; see also Fisher v. City of Las
Cruces, 

, 899 (10th Cir. 2009) (“Accordingly, our precedent
requires a showing in a handcuffing case of an actual, non-de minimis
physical, emotional, or dignitary injury to succeed on a claim.”).
3
       See Scott v. Hern, 

, 911 (10th Cir. 2000).
4
       See 

.

                                       4
independent grounds, the appellant must challenge each of those

grounds.”).

         We agree with the district court that the evidence did not show a

causal link between Officer Miller’s actions and an actual injury to Mr.

Zartner. To establish a causal link, Mr. Zartner needed to present expert

medical testimony. But he failed to do so. 5

IV.      In district court and his opening appeal brief, Mr. Zartner urged
         causation based solely on an inapplicable theory of “aggregation.”

         The district court apparently acknowledged that Mr. Zartner’s

fracture had constituted an actual injury. Despite the existence of an actual

injury, the court concluded that Mr. Zartner had failed to present adequate

evidence of a causal link between the injury and Officer Miller’s use of

force.

         In both district court and his opening appeal brief, Mr. Zartner urged

causation based solely on a theory of aggregation. Appellant’s Opening Br.

at 18 (Mr. Zartner arguing that he had “suffered serious injuries as the

result of the aggregate conduct” of Officer Miller and others); see also

Appellant’s App’x at 106 (virtually identical language in Mr. Zartner’s

response to Officer Miller’s summary-judgment motion in district court).

Under a theory of aggregation, the court considers the conduct of multiple


5
     Because we affirm on the issue of causation, we need not decide
whether a fact-finder could reasonably have inferred that Officer Miller
had known that the handcuffs were too tight.
                                        5
officers “in the aggregate.” Pauly v. White, 

, 1214 (10th Cir.

2017), cert. denied, 

(2018).

      Mr. Zartner pointed out that we have sometimes aggregated officer

conduct in § 1983 cases. See Estate of Booker v. Gomez, 

,

421–22 (10th Cir. 2014). For example, we have aggregated officers’

conduct when

           two officers worked together to handcuff and subdue an
            arrestee 6 and

           four officers participated in a coordinated use of force, which
            included handcuffing the arrestee, applying a carotid hold,
            putting pressure on the arrestee’s back, and using a taser. 7

But when the officers did not coordinate, we have considered each

officer’s liability based solely on his or her own acts. See, e.g., 

.

      Invoking the aggregation theory, Mr. Zartner contended that a

reasonable jury could find causation by combining Officer Miller’s

handcuffing with (1) the deputy sheriffs’ later use of force to obtain

fingerprints and (2) other officers’ later use of handcuffs.




6
      Weigel v. Broad, 

, 1148–49, 1151–53, 1153 n.4 (10th
Cir. 2008).
7
     Estate of Booker v. Gomez, 

, 413–16, 421–22 (10th Cir.
2014).

                                      6
      This contention stretches the theory of aggregation beyond our prior

cases. Officer Miller played no role in the deputy sheriffs’ use of force to

obtain fingerprints, and the deputies’ use of force played no role in the

handcuffing of Mr. Zartner: The deputies and Officer Miller used force

against Mr. Zartner in different episodes on different days, at different

places, and for different purposes. And no evidence connects Officer

Miller to the later use of handcuffs on Mr. Zartner. We therefore conclude

that Mr. Zartner failed to show causation through a theory of aggregation.

V.    In his appellate reply brief, Mr. Zartner added an unsupported
      theory of causation between Officer Miller’s use of force and the
      wrist fracture.

      In his appellate reply brief, Mr. Zartner argued that Officer Miller’s

use of tight handcuffs, by itself, had caused the wrist fracture. 8 But this

argument was not presented either in district court or in Mr. Zartner’s

opening appeal brief.

      In district court, Officer Miller denied evidence of a causal link

between his conduct and an injury that was more than de minimis.

Appellant’s App’x at 49–50. In response, Mr. Zartner invoked his

aggregation theory. Appellant’s App’x at 105–07. But he didn’t argue in

district court that Officer’s Miller conduct had alone caused the injury. Mr.



8
     After a third incident (see pp. 6–7, above), Mr. Zartner was
diagnosed with de Quervain tenosynovitis, paresthesia, and other injuries.

                                       7
Zartner thus forfeited this theory. See Stender v. Archstone-Smith

Operating Trust, 

, 

, at *3 (10th Cir. 2018)

(holding that the appellants forfeited a legal theory by failing to present it

in district court).

      Mr. Zartner also bypassed an opportunity to include this theory in his

opening appeal brief. He instead argued that his injuries were “indivisible”

based on the combination of force used by Officer Miller and the deputy

sheriffs. See Appellant’s Opening Br. at 18 (“The injury caused by the

handcuffs was the first in a series of indivisible injuries by a series of

actors thus making all actors jointly and severally liable.”); see also Dist.

Ct. Doc. No. 98 at 9 (using virtually identical language in Mr. Zartner’s

response to Officer Miller’s summary-judgment motion in district court).

      Mr. Zartner reverses course in his appellate reply brief, arguing for

the first time that his fracture was caused solely by Officer Miller’s use of

handcuffs. But at this point it was too late for Mr. Zartner to change his

theory of causation. See Anderson v. Spirit Aerosystems Holdings, Inc.,

, 1236 n.2 (10th Cir. 2016) (holding that adding an argument

in the reply brief was “too late”). So even if Mr. Zartner had asserted this

theory in district court, he would have waived it by omitting it in his




                                       8
opening appeal brief. See 

waived their challenge by

waiting to make it in their reply brief.”). 9

      Mr. Zartner’s new theory is not only unpreserved but also

unsupported. For this theory, Mr. Zartner relied on his declaration, a

photograph, a report summarizing the results of an x-ray, a declaration by

Dr. Symonds, and Dr. Christian Stob’s deposition testimony. But these

pieces of evidence do not provide the required medical evidence of a

causal link between Officer Miller’s use of allegedly tight handcuffs and

the wrist fracture.

      In his declaration, Mr. Zartner stated that he had no wrist pain before

getting handcuffed by Officer Miller. Appellant’s App’x at 146.

      Along with the onset of pain, Mr. Zartner discussed a photograph of

his right hand, stating that it “shows a prominent abrasion overlying the

area under which the triquetral bone is located.” 

only




9
       In the “summary of argument” section in his opening appeal brief,
Mr. Zartner stated that “the District Court [had] ignored facts from which
it could reasonably be inferred that the handcuffing caused the triquetral
fracture.” Appellant’s Opening Br. at 12. But Mr. Zartner did not elaborate
on the theory in his opening brief; there he argued only aggregation. See

Mr. Zartner’s stray sentence in his summary of argument did
not constitute adequate briefing of a causation theory untethered to his
aggregation theory. See Christian Heritage Acad. v. Okla. Secondary Sch.
Activities Ass’n, 

, 1031 (10th Cir. 2007) (concluding that a
brief discussion in the introduction-to-argument section did not adequately
present a distinct argument).

                                        9
photograph in the summary-judgment record is blurry and shows no

obvious abrasions on Mr. Zartner’s right wrist.

      X-rays were taken several days after deputy sheriffs had used

nunchucks to apply pressure to Mr. Zartner’s wrists. The x-rays revealed a

triquetral chip fracture in his right wrist.

      Lastly, Mr. Zartner pointed to Dr. Symonds’s declaration and Dr.

Stob’s deposition testimony. In the declaration, Dr. Symonds stated that in

his professional medical opinion, the x-rays of Mr. Zartner’s right wrist

showed a bone fracture of “indeterminate” age. Appellant’s App’x at 110.

And Dr. Stob testified that

           tight handcuffs can cause compression neuropathy and fractures
            and

           the symptoms of nerve compression include temporary
            numbness and tingling.

      The resulting question is whether Mr. Zartner’s evidence of causation

is enough to create a triable issue of fact. To answer, we must decide

whether expert medical testimony is necessary to create a triable issue of

fact on causation. This question turns on whether causation here would

constitute a medical question or a question that a lay person could answer

based on ordinary experience.

      The testimony of a medical expert is not always necessary to

establish causation. For example, expert testimony might be unnecessary to
                                       10
find causation when a brawl leads to a broken nose or black eye. See Myers

v. Ill. Cent. R. Co., 

, 643 (7th Cir. 2010) (stating that expert

testimony is unnecessary when someone breaks a leg from a vehicle crash

because causation would be understandable to a layperson). But when an

injury lacks an obvious origin and multiple causes are possible, expert

medical testimony is necessary to prove causation between a use of force

and an injury. 10

      In our view, the tight handcuffing was not the obvious cause of Mr.

Zartner’s wrist fracture. We assume, for the sake of argument, that Mr.

Zartner’s fracture could have resulted from Officer Miller’s use of tight

handcuffs. But by the time that the fracture was diagnosed, a group of

deputy sheriffs had used force on Mr. Zartner’s wrists, applying pressure

with nunchucks. And Dr. Stob testified that this use of force could have

caused a fracture.

      Given the two separate uses of force that could have caused the

fracture, causation entails a medical question beyond a layperson’s


10
      See Felkins v. City of Lakewood, 

, 651–52 (10th Cir.
2014); Franklin v. Shelton, 

, 97 (10th Cir. 1957); accord
Albertson v. Norris, 

, 765–66 (8th Cir. 2006) (holding that the
defendants were entitled to summary judgment on a § 1983 claim because
the plaintiff had failed to present expert medical testimony showing a
causal link between the lack of medication and a stroke, reasoning that the
stroke could have had many other causes); 

(“But
when there is no obvious origin to an injury and it has ‘multiple potential
etiologies, expert testimony is necessary to establish causation.’” (quoting
Wills v. Amerada Hess Corp., 

, 46–47 (2d Cir. 2004))).
                                      11
ordinary experience. See Fane v. Zimmer, Inc., 

, 131 (2d Cir.

1991) (concluding that expert medical testimony was necessary on the

“medical question” of “[w]hat causes a bone to fracture” because the injury

had been complex, involved a complicated surgery, and causation went

“beyond the sphere of the ordinary juryman”). In light of this medical

question, Mr. Zartner needed to present expert medical testimony tying the

fracture to Officer Miller’s use of tight handcuffs. See Harvey v. United

States, 

, 952–53 (10th Cir. 2012) (upholding summary

judgment for the defendant because expert testimony was necessary to

show causation between improper medical treatment and further injury to a

hand that had been fractured); accord Smith v. Curran, 

, 771

(Colo. App. 1970) (requiring expert testimony because “the cause of an

infection” is a matter lying “within the field of medical experts”). 11 Mr.

Zartner did not present this testimony. As a result, the new theory of

causation would fail even if Mr. Zartner had preserved it in district court

and his opening appeal brief.




11
      Though causation under § 1983 involves an issue of federal law,
opinions by Colorado appellate courts provide useful guidance. See Barnes
v. Anderson, 

, 158–59 (2d Cir. 1999) (stating that “state tort
analogs” bear on proximate cause under § 1983 even though the issue
involves federal law).
                                      12
VI.   Conclusion

      The district court correctly concluded that the summary-judgment

evidence would not permit a reasonable fact-finder to draw a causal link

between Officer Miller’s use of allegedly tight handcuffs and an actual

injury to Mr. Zartner. We therefore affirm the district court’s grant of

summary judgment to Officer Miller.


                                       Entered for the Court


                                       Robert E. Bacharach
                                       Circuit Judge




                                     13