A former sheriff's deputy who suffered a career-ending back injury when shocked by a Taser stun gun during training has lost an attempt to revive his product liability lawsuit.

The Arizona Court of Appeals on Monday upheld a Maricopa County Superior Court jury's verdict for Scottsdale-based Taser International Inc. in a lawsuit filed by Samuel Powers, a former county sheriff's deputy.

A three-judge Court of Appeals panel ruled unanimously that a trial judge was correct to rule that Powers wasn't entitled to have jurors instructed they could hold Taser liable for dangers that the company didn't learn of until Powers' injury.

Arizona has not adopted a so-called "hindsight" test for strict liability product claims involving allegations of failing of defects, the Court of Appeals said.

Employing the hindsight test in warning defect cases "would be tantamount to imposing a duty on manufacturers to warn of unknowable dangers," Judge Daniel A. Baker wrote for the panel.

Powers, a 16-year veteran of the Maricopa County Sheriff's Office, was shocked July 16, 2002, while participating in an MCSO training and certification course on Taser's M-26 stun gun.

According to court papers, he suffered a compression fracture of a spinal disc and, during treatment, was discovered to have severe osteoporosis, a condition that weakens bones. His doctor ordered him restricted to light duty, and Powers resigned as a deputy on June 2003.

Powers' suit alleged that Taser's M-26 stun gun was unreasonably dangerous and defective because it lacked adequate instructions and warnings, but Taser argued that it did not know that the muscle contractions produced by the weapon were strong enough to cause a fracture.

The ruling also upheld the trial court's order that Powers reimburse Taser for its expert witness fees and costs because Powers had rejected a pretrial settlement offer that would have been more favorable to him than the eventual outcome of the case.

Powers argued that the payment order was improper because the settlement offer was conditioned on its terms being kept confidential, but the Court of Appeals said that requirement didn't violate state court rules.

Thomas C. Wilmer, one of Powers' attorney, said he hadn't seen the Court of Appeals ruling but that it was likely that Powers would ask the Arizona Supreme Court to review it.