UNITED STATES COU RT OF APPEALS
FOR THE TENTH CIRCUIT

________________ _________________ KENNETH R. ZARTNER, Plaintiff - Appellant,

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

________________ _________________ ORDER AND JUDGMENT *

________________ _________________ Before BRISCOE , BACHARACH , and CARSON , Circuit Judges.

________________ _________________ This appeal grew out of Officer Shawn Mille r’s handcuffing of M r. Kenneth Zartner duri ng an arrest. In the af termath, 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 di strict court granted the motio n.

* This order and judg ment does not constit ute binding precedent except under the doctrines of law of the case, res judicata, and colla teral estoppel. But the order and judgment may be cited if otherwise appropriat e. See Fed. R. App. P. 32.1(a); Te nth Cir. R. 32.1(A).

1 Mr. Zartner also sued the City and County of Denver, a jail n urse, and six deputy sheriffs. But this appeal involves only Mr. Zart ner’s § 1983 claim against Officer Miller for the allegedly tight handcuffs. FILED United States Court of Appeals Tenth Circuit 

### January 9, 2019
Elisabeth A. Shumaker Clerk of Court2 We affirm because Mr. Z artner did not prese nt adequate evidence of a causal link between the allegedly tight handcuffs and an actu al injury. Without adequate evidence of a c ausal link, Mr. Z artner cannot prevail against Officer Miller.
I. Mr. Zartner was diagnos ed with a fracture in his right wrist af ter two separate uses of force. Officer Miller arrested Mr. Zartn er for aggravated theft of a m otor vehicle, handcuffing him in the process of making the arrest. M r. Zartner was then taken to a detention cen ter, where he was examined by medical staff. During the examination, no injuries were reported or obs erved. The next day, Mr. Zartner was to be fingerprinted. He refused to cooperate, so a group o f deputy sheriffs fo rced 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 di dn’t respond and the n urse again observed no injuries. Later that day, Mr. Zartner compl ained about wrist pain, leadin g to an examination of his wrists and the taking of x-rays. From the x-rays, Dr. David Symonds diagnose d Mr. Zartner with a fracture in his righ t wrist.
II. When reviewing the grant of su mmary judgment, we engage in de novo review. We review de novo a dis trict court’s grant of a motion for sum mary judgment. Lamb v. Norwood , 899 F.3d 1159, 1162 (10t h Cir. 2018). The3 motion must be granted if the moving party shows that (1) the p arties do not genuinely dispute a ny material facts and (2) the moving par ty is entitled to judgment as a matter of law based on those facts. F ed. R. Civ. P. 56(a). When applying this standard, we view the evidence in the light most favorable to the nonmoving party and draw a ll reasonable i nferences in this party’s favor. Havens v. Colo. Dep’t of Corr. , 897 F.3d 1250, 1259 (10th Cir. 2018). We must apply this standard in t he context of qualified immunit y, which shields office rs from civil damages if their conduct does not violate a clearly established right. Harlow v. Fitzgerald , 457 U.S. 800, 818 (1982);
Schwartz v. Booker , 702 F.3d 573, 579 ( 10th Cir. 2012). Once an officer asserts qualified immunity, the plaintiff must

 allege facts showing that the off icer violated a constitutional right and

 identify case law showing th at this right was clearly established when t he officer acted.
See Schwartz , 702 F.3d at 579. In this circuit, unduly tight h andcuffing can c onstitute exces sive force under the Fourth and Fourteenth A mendments. Cortez v. McCauley , 478 F.3d 1108, 1129 (10th Cir. 2007) (en banc ). To trigger liab ility for unduly tight handcu ffs, however, the pla intiff must show4  an actual injury, 2

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

 the officer’s knowled ge that the handcu ffs were too tight. 4
III. The district court c oncluded that there wa s no constitutional violation based on two independent grounds. The district court granted su mmary judgment to Officer Miller b ased on qualified immunity, concluding that Mr. Zartner had failed t o show a violation of his constitutional r ights. This conclusion rested on two independent grounds:
1. Mr. Zartner had fail ed 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 wer e too tight. Because the district court gave t wo independent rationales, Mr. Zartner can prevail on appeal only by succ essfully challenging both. See Lebahn v. Nat’l Farmers Union Unif. Pension Plan , 828 F.3d 1180, 1188 (10th Cir. 2016) (“When a district court dism isses a claim on two or more

2 See Cortez , 478 F.3d at 1129 & n.24; see also Fisher v. City of Las Cruces , 584 F.3d 888, 899 (10th Cir. 2009 ) (“Accordingly, our precede nt requires a showing in a handcuffi ng case of an actual, non-de m inimis physical, emotional, o r dignitary injury t o succeed on a claim. ”).

3 See Scott v. Hern , 216 F.3d 897, 911 (1 0th Cir. 2000).

4 See Cortez , 478 F.3d at 1129.5 independent grounds, t he appellant must ch allenge each of those grounds.”). We agree with the dist rict court that the evidence did not show a causal link between O fficer Miller’s actions and an actual inju ry to Mr. Zartner. To establish a causal link, Mr. Zartner needed to pres ent expert medical testimony. But he failed to do so. 5
IV. In district court and his openin g appeal brief, Mr. Zartner urg ed causation based solely on an i napplicable theo ry of “aggregatio n.” The district court app arently acknowledged that Mr. Zartner’s fracture had constituted an actual injury. Despite the existenc e of an actual injury, the court concl uded that Mr. Zartner had failed to pres ent adequate evidence of a causal link between the inj ury and Officer Miller ’s use of force. In both district court and his opening appeal brief, Mr. Zartne r urged causation based solely on a theory of aggregation. Appellant’s Opening Br. at 18 (Mr. Zartner arguing that he had “suffered serious injuri es as the result of the aggregate conduct” of Officer Miller and others); see also Appellant’s App’x at 106 (virtual ly identical la nguage in Mr. Z artner’s response to Officer Miller’s summa ry-judgment motion in distric t court). Under a theory of aggr egation, the court c onsiders the conduct of multiple

5 Because we affirm on the issue of causation, we need not deci de whether a fact-finder could reasonably have inferred that Offic er Miller had known that the handcuffs were too tight.6 officers “in the aggregate.” Pauly v. White , 874 F.3d 1197, 1214 (10th Cir. 2017), cert. denied , 138 S. Ct. 2650 (2018). Mr. Zartner poin ted out that we have som etimes aggregated offic er conduct in § 1983 cases. See Estate of Booker v. Gomez , 745 F.3d 405, 421–22 (10th Cir. 2014). For example, we ha ve aggregated office rs’ 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 handcuffi ng the arrestee, applyi ng a carotid hold, putting pressure on the arrestee’s back, and using a taser. 7
But when the officers d id not coordinate, we have considered ea ch officer’s liability based sole ly on his or her own acts. See, e.g. , Pauly , 874 F.3d at 1214. Invoking the aggregat ion theory, Mr. Zartn er contended that a reasonable jury coul d find causati on by combining Officer Mille r’s handcuffing with (1) the deputy sheriffs’ later use of force to obtain fingerprints and (2) other offi cers’ later use of handcuffs.

6 Weigel v. Broad , 544 F.3d 1143, 1148–49, 1151–53, 1153 n.4 (10th Cir. 2008).

7 Estate of Booker v. Gomez , 745 F.3d 405, 413–16 , 421–22 (10th Cir. 2014).7 This contention stretches the th eory of aggrega tion beyond our prior cases. Officer Miller p layed no role in the deputy sheriffs’ us e of force to obtain fingerprints, and the depu ties’ use of force played no r ole in the handcuffing of Mr. Zartner: The d eputies and Officer Miller use d force against Mr. Zartner in different episodes on different days, at different places, and for different purpo ses. And no evidence connects Of ficer Miller to the later use of handcuffs on Mr. Zartner. We therefo re conclude that Mr. Zartner failed to show causation through a theory of a ggregation.
V. In his appellate reply brief, Mr. Zartner added an unsupported theory of causation between Offi cer Miller’s use of force and t he wrist fracture. In his appellate reply brief, Mr . Zartner argued that Officer M iller’s use of tight handcuffs, by itsel f, had caused th e wrist fractur e. 8 But this argument was not presented either in district court or in Mr. Z artner’s opening app eal brief. In district court, Officer Miller denied evidence of a causal l ink between his conduct and an inj ury that was more than de minimis

. Appellant’s App’x at 49–50. In re sponse, Mr. Zartner invoked hi s aggregation theory. Appellant’s App’x at 105–07. But he didn’t argue in district court that Officer’s M iller conduct had alone caused t he injury. Mr.

8 After a third incident ( see pp. 6–7, above), Mr. Zartner was diagnosed with de Quervain te nosynovitis, paresthesia, and othe r injuries.8 Zartner thus forfeited this theory. See Stender v. Archstone-Smith Operating Trust , 910 F.3d 1107, 2018 WL 6423923, at *3 ( 10th Cir. 2018) (holding that the appellants forfeited a legal theory by failin g to present it in district court). Mr. Zartner also bypassed an oppo rtunity to includ e this theory in his opening appeal brief. He instead argued that his injuries were “indivisible” based on the combina tion of force used by Officer Miller and th e 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 jo intly and severa lly liable.”); see also Dist. Ct. Doc. No. 98 at 9 (using virtually identical language in Mr. Zartner’s response to Officer Miller’s summa ry-judgment motion in distric t court).
Mr. Zartner reverses c ourse in his appellate reply brief, argui ng for the first time that his fractur e was caused solely by Officer M iller’s use of handcuffs. But at this point it wa s too late for Mr. Zartner to change his theory of causation. See Anderson v. Spirit Ae rosystems Ho ldings, Inc. , 827 F.3d 1229, 1236 n.2 (10th Cir . 2016) (holding that adding a n argument in the reply brief was “too lat e”). So even if M r. Zartner had asserted this theory in district court, he wou ld have wa ived it by omitting i t in his9 opening appeal brief. See id. (“The plaintiffs waive d their challenge by waiting to make it in th eir reply brief.”). 9
Mr. Zartner’s new the ory is not only unpreserved but also unsupported. For this t heory, Mr. Zartner r elied on his declara tion, a photograph, a report summarizing the results of an x-ray, a dec laration by Dr. Symonds, and Dr. Christia n Stob’s deposition testimony. But these pieces of evidence do not provide the required medical evidence of a causal link between O fficer Miller’s use of allegedly tight han dcuffs and the wrist fracture. In his declaration, Mr. Zartner stated that he had no wrist pai n before getting handcuffed by Officer Mil ler. Appellant’s App’x at 146. Along with the onset of pain, Mr. Zartner discussed a photograp h of his right hand, stating that it “shows a prominent abrasion overlying the area under which the triqu etral bone is located.” Id. But the only

9 In the “summary of argument” s ection in his opening appeal br ief, 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 n ot elaborate on the theory in his opening brief; there he argued only aggreg ation. See id. at 16–19. Mr. Zartner’s stray sentence in h is summary of argume nt did not constitute adequate briefing of a causation theory untether ed to his aggregation theory. See Christian Heritage Acad . v. Okla. Secondary Sch. Activities Ass’n , 483 F.3d 1025, 1031 (10th Cir . 2007) (concluding that a brief discussion in the introduction-to-argument section did no t adequately present a distinct argument).10 photograph in the summary-judgment record is blurry and shows n o 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 poi nted to Dr. Symonds’ s declaration and Dr

. Stob’s deposition testimony. In t he declaration, Dr. Symonds st ated that in his professional medical opinion, the x-rays of Mr. Zartner’s r ight wrist showed a bone fracture of “inde terminate” age. A ppellant’s App’ x at 110. And Dr. Stob tes tified that

 tight handcuffs can cause compression neuropathy and fractures and

 the symptoms of nerve comp ression include temporary numbness and tingling.
Id. at 150–51. The resulting question is whether Mr. Zartner’s evidence of cau sation is enough to create a triable issu e of fact. To a nswer, we must decide whether expert medical testimony is necessary to create a triab le issue of fact on causation. This question turns on whether causation her e would constitute a medical question or a question that a lay person c ould answer based on ordinary experience. The testimony of a medical expert is not always necessary to establish causation. F or example, expert t estimony might be unn ecessary to11 find causation when a b rawl leads to a broken nose or black eye

. See Myers v. Ill. Cent. R. Co. , 629 F.3d 639, 643 ( 7th Cir. 2010) (stating that expert testimony is unnecessary when some one breaks a leg from a vehic le crash because causation would be understandable to a layperson). But when an injury lacks an obviou s origin and mu ltiple 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 handcuffi ng was not the obvious cause of Mr. Zartner’s wrist fracture. We assu me, for the sake of argument, that Mr. Zartner’s fracture co uld have resu lted from Offi cer Miller’s us e of tight handcuffs. But by the time that the fractur e was diagnose d, a group of deputy sheriffs had u sed force on Mr. Zart ner’s wrists, applyin g pressure with nunchucks. A nd Dr. Stob testified th at this use of force c ould have caused a fracture. Given the two separate uses of force that could have caused the fracture, causation entails a med ical question beyond a laypers on’s

10 See Felkins v. City of Lakewood , 774 F.3d 647, 651–52 (10th Cir. 2014); Franklin v. Shelton , 250 F.2d 92, 97 (1 0th Cir. 1957); accord Albertson v. Norris , 458 F.3d 762, 765–66 (8th Cir . 2006) (holdi ng that the defendants were entitle d to summary judgment on a § 1983 claim because the plaintiff had failed to pre sent expert medical testimony sh owing a causal link between the lack of medication and a stroke, reason ing that the stroke could have had many other causes); Myers , 629 F.3d at 643 (“But when there is no obvious origin to an injury and it has ‘multip le potential etiologies, expert testimony is necessary to establish causatio n.’” (quoting Wills v. Amerada Hess Corp. , 379 F.3d 32, 46–47 (2d Cir. 2004))).12 ordinary experience. See Fane v. Zimmer, Inc. , 927 F.2d 124, 131 (2d Cir. 1991) (concluding that expert medical tes timony was necessary o n the “medical question” of “[w]hat causes a bone to fracture” becaus e the injury had been complex, involved a complicated surgery, and causation went “beyond the sphere of the ordinary j uryman”). In li ght of this medical question, Mr. Zartner needed to present expert medical testimon y tying the fracture to Officer Miller’s use of tight handcuffs. See Harvey v. United
States , 685 F.3d 939, 952–53 (10th Ci r. 2012) (uphold ing summary judgment for the defendant because expert testimony was necessa ry to show causation between improper m edical treatment and further i njury to a hand that had been fractured); accord Smith v. Curran , 472 P.2d 769, 771 (Colo. App. 1970) (requiring exper t testimony because “the caus e of an infection” is a matter lying “wi thin the field of medical exper ts”). 11 Mr. Zartner did not present this tes timony. As a result, the new th eory of causation would fail even if Mr. Zartner had preserved it in di strict court and his opening appeal brief.

11 Though causation und er § 1983 involves an issue of federal la w, opinions by Colorado appellate courts pr ovide useful guidance. See Barnes v. Anderson , 202 F.3d 150, 158–59 (2d Cir. 1999) (stating that “state tort analogs” bear on proximate cau se under § 1983 ev en though the i ssue involves federal law).13 VI. Conclusion The district court correctly c oncluded th at the summary-judgme nt evidence would not pe rmit a reasonable fact -finder to draw a ca usal link between Officer Miller’s use of a llegedly tight handcuffs and a n actual injury to Mr. Zartner. We theref ore affirm the district court’s grant of summary judgment t o Officer Miller.

Entered for the Court

Robert E. Bacharach Circuit Judge