## Facts

- Robert Cisar purchased a chain saw from a Home Depot store in Iowa.
- Cisar experienced repeated incidents of the chain coming off during use and returned to the store multiple times, where an employee adjusted the chain and later replaced the bar and chain.
- After one earlier incident, Cisar reported the chain came off and cut his finger; Home Depot again serviced the saw.
- The parties disputed whether Home Depot ultimately replaced the saw: Cisar and an employee said a manager refused replacement, while the manager testified he provided a new saw in a sealed box.
- During a later use, the chain came off, caught the wood, and struck Cisar in the head, causing serious injuries including a brain injury; Cisar claimed resulting personality and behavioral changes.
- Cisar sued for negligent failure to repair, negligent failure to exchange (replace) the saw, and negligent post-sale failure to warn; his wife, Dr. Suzanne Munns, asserted loss of consortium.

## Issues

1. Whether the district court abused its discretion by permitting cross-examination and related evidence about Cisar’s pre- and post-injury temper and behavior after plaintiffs claimed injury-caused personality changes.
2. Whether the district court abused its discretion by excluding a witness not identified on plaintiffs’ pretrial witness list.
3. Whether summary judgment was proper on the post-sale failure-to-warn claim where evidence did not show Home Depot knew the saw was defective or unreasonably dangerous, and where the jury’s findings affected causation.
4. Whether any issues raised in Home Depot’s cross-appeal warranted disturbing the judgment after a defense verdict.

## Decision

- The Eighth Circuit affirmed the district court’s judgment in full.
- The court held the challenged cross-examination and behavioral evidence fell within the district court’s discretion because plaintiffs placed Cisar’s personality and behavioral changes in dispute as damages.
- The court found no abuse of discretion in excluding the undisclosed witness, emphasizing trial courts’ authority to enforce disclosure and case-management requirements.
- The court upheld summary judgment on the post-sale failure-to-warn claim, concluding the record did not support the necessary knowledge component and that, in light of the jury’s findings (including replacement of the saw), the theory could not have changed the outcome.
- The court rejected or treated as academic the cross-appeal issues in view of the affirmed defense verdict.

## Legal Principles

- Evidentiary rulings on the scope of cross-examination and admissibility of related conduct evidence are reviewed for abuse of discretion and are reversed only upon a showing of unfair prejudice affecting the trial’s fairness.
- When a plaintiff claims injury-related personality or behavioral change as an element of damages, the defendant may probe pre- and post-injury behavior to test causation and the existence and extent of the claimed change.
- District courts have broad discretion to enforce pretrial disclosure rules, including excluding witnesses not properly identified, particularly where relevance is not shown.
- A negligence-based post-sale failure-to-warn claim requires sufficient evidence that the defendant knew (or had reason to know) of a defect or unreasonable danger and that the failure to warn was causally connected to the injury; intervening facts found by the jury may defeat causation.

## Conclusion

The Eighth Circuit left intact a defense verdict and pretrial summary judgment, holding that the trial court’s evidentiary and case-management decisions were within its discretion and that the post-sale failure-to-warn theory lacked the required proof of knowledge and causation under the facts as resolved at trial.


Cisar v. Home Depot U.S.A., Inc., 351 F.3d 800 (8th Cir. 2003)