David v. Hernandez, 13 Cal. App. 5th 692

Hernandez, a tractor-trailer driver, turned across the southbound lane and reentered northbound traffic on Pacific Coast Highway; his 45-ft, 45,000-lb flatbed trailer was struck on the left side by Joshua David's southbound minivan, causing catastrophic left shoulder injuries.
David was unconscious at the scene, extricated after ~45 minutes, and suffered an open fracture/necrosis of the humeral head requiring partial shoulder arthroplasty; he sought damages including future surgeries.
At retrial the jury found Hernandez negligent and awarded David $3,317,580, which included four future shoulder surgeries at $161,750 each.
Hernandez sought to admit expert testimony that David was driving impaired by marijuana based on a preliminary urine screen positive for THC; the trial court excluded that testimony on a motion in limine for lack of foundation under Evidence Code § 801.
Hernandez challenged (1) exclusion of the marijuana-impairment expert and (2) the sufficiency of evidence supporting an award for four future shoulder surgeries; the Court of Appeal affirmed.

Issue	Plaintiff's Argument (David)	Defendant's Argument (Hernandez)	Held
Admissibility of expert testimony that urine screen showed marijuana impairment at time of crash	Exclusion proper; preliminary test and lack of foundation make impairment speculative	Positive urine screen and medical literature support inference of active THC and impairment 36–48 hours after use	Court affirmed exclusion: preliminary screen, no quantification of active THC, alternative explanations (trauma/stress), and analytical gaps made opinion speculative (district court gatekeeping under Evidence Code § 801)
Sufficiency of evidence for four future shoulder surgeries	Testimony and life-care plan sufficiently established reasonable certainty of one arthroplasty and three 15-year revisions based on prosthesis wear and Dr. Norris’s statements	Only one future surgery is reasonably certain; additional revisions speculative without timing/probability from treating surgeon	Court held substantial evidence supported four surgeries: Dr. Norris’s opinions on socket wear and need for socket procedures, Bennett’s life-care plan (based on Dr. Norris), and Nordstrand’s testimony provided a reasonable basis for jury to find four surgeries reasonably certain

Sargon Enterprises, Inc. v. University of Southern Cal., 55 Cal.4th 747 (2012) (trial court must exclude speculative expert opinion; acts as gatekeeper under Evid. Code § 801)
In re Lockheed Litigation Cases, 115 Cal.App.4th 558 (2004) (abuse of discretion standard for exclusion of expert testimony)
Garcia v. Duro Dyne Corp., 156 Cal.App.4th 92 (2007) (future damages recoverable when detriment is reasonably certain)
Rivard v. Board of Pension Commissioners, 164 Cal.App.3d 405 (1985) (substantial evidence standard on appeal; view evidence favorably to prevailing party)
Regalado v. Callaghan, 3 Cal.App.5th 582 (2016) (jury may find future surgery reasonably certain from expert testimony)
People v. Sanchez, 63 Cal.4th 665 (2016) (case-specific out-of-court statements related by experts can be hearsay)
Lockheed Martin Corp. v. Superior Court, 29 Cal.4th 1096 (2003) (expert opinion value depends on its factual basis and reasoning)
Hegglin v. Worker's Comp. App. Bd., 4 Cal.3d 162 (1971) (necessity of assessing material facts and reasons underpinning medical opinions)