BOSTON — A woman isn’t legally responsible for injuries her boyfriend suffered while they were having consensual sex more than a decade ago, a state appeals court ruled Monday.

The man, identified only as John Doe in court papers, filed suit against the woman in 1997, claiming she was negligent when she suddenly changed positions, landed awkwardly on him and fractured his penis.

The man underwent emergency surgery in September 1994, “endured a painful and lengthy recovery” and has suffered from sexual dysfunction that hasn’t responded to medication or counseling, the appeals court said.

Although the woman may have exposed her boyfriend to “some risk of harm,” the three-judge panel said her conduct during the sexual encounter wasn’t “wanton or reckless” and can’t support a lawsuit. The man’s lawsuit already has been thrown out by judges in Salem District Court and Essex Superior Court.

The appeals court upheld those rulings while noting that its ruling doesn’t apply to cases where someone has negligently infected a partner with a sexually transmitted disease.

“There are no comprehensive legal rules to regulate consensual sexual behavior,” Justice Joseph Trainor wrote. “In the absence of a consensus of community values or customs defining normal consensual conduct, a jury or judge cannot be expected to resolve a claim that certain consensual sexual conduct is undertaken without reasonable care.”

The man’s attorney, John Greenwood, said he is likely to appeal Monday’s ruling to the state’s highest court.

“It’s a case that hasn’t been seen before in Massachusetts,” he said.

Greenwood argued that consensual sex doesn’t mean “anything goes. … The fact that some behavior was agreed to by the parties doesn’t mean all behavior was agreed to by the parties.”

The woman’s attorney didn’t immediately return a telephone call Monday.