A U.S. judge almost halved the award in a December jury verdict that ordered Johnson & Johnson and its DePuy Orthopaedics unit to pay more than $1 billion to plaintiffs in six lawsuits who said they were injured by DePuy's Pinnacle hip implants.

U.S. District Judge Ed Kinkeade in Dallas cited "constitutional considerations" that limit how much plaintiffs may recover in punitive damages but upheld the jury's findings that the implants were defectively designed and that the companies failed to warn consumers about the risks.

Around $500 million of punitive damages would be cut from the more than $1 billion awarded to the plaintiffs who are California residents that were implanted with the hip devices and experienced tissue death, bone erosion and other injuries they attributed to design flaws.

The complainants claimed the companies promoted the implants as lasting longer than devices that include ceramic or plastic materials.

DePuy ceased selling the metal-on-metal Pinnacle devices in 2013 after the U.S. Food and Drug Administration strengthened its regulations on artificial hips.

J&J and DePuy paid $2.5 billion that year to settle more than 7,000 lawsuits over its ASR metal-on-metal hip devices.