3M’s legal strategy of winning thousands of hospital-infection lawsuits by undermining their scientific credibility failed on Wednesday, as U.S. District Judge Joan Ericksen ruled that the plaintiffs can present their preferred expert witnesses to support their claims in court.

Maplewood-based 3M sells a forced-air patient-warming device called the Bair Hugger, which is widely used in hospitals to keep patients warm during surgery as a way to promote healing and prevent infections.

Thousands of people say the device caused their infections during joint-replacement surgery by blowing contaminated air on them and disrupting the normal flow of air that keeps contaminated particles out of the surgical field.

“There is no evidence that the 3M Bair Hugger warming system causes infections,” a 3M spokeswoman said. “Our product is a safe and effective tool for warming patients before, during and after surgery. 3M is eager to proceed to trial early next year to defend the integrity of the 3M Bair Hugger warming system.”

The plaintiffs have no direct evidence of a bacteria-laden particle being stirred up by the Bair Hugger and landing in anyone’s surgical incision. Rather, the plaintiffs have presented experts who testified that this likely happens, and a computer model showing how it would happen. 3M asked Ericksen to exclude the plaintiffs’ experts from the case and then grant summary judgment because of a lack of expert opinions.

A three-day hearing was held in October. Ericksen on Wednesday declined to exclude any of the experts from the case or grant the 3M motion for summary judgment.

Rather, she ruled that both sides are free to cross-examine each other’s experts and present rebuttal testimony before a jury.

In a 30-page ruling that resolved 16 different pending motions to exclude experts on both sides, Ericksen quoted past court rulings that found that judges must exclude experts only when the expert opinions are so fundamentally unsupported that they can’t offer assistance to the jury.