The U.S. Food and Drug Administration is ordering Johnson & Johnson's DePuy Orthopedics unit to halt sales of its Corail Hip System because the company is marketing it for an unapproved use, according to a warning letter made public on Tuesday.

DePuy's TruMatch Personalized Solutions System artificial knees also lack FDA approval, the agency said. The FDA asked the company to submit information so it can decide whether the product can be legally marketed.

The letter comes amid a tighter crackdown on medical devices, including possible changes to the approval process, under Margaret Hamburg, whom the Obama administration appointed to head the FDA.

For DePuy's Corail hip product, FDA said the device was only supposed to be used without cement but that a brochure on the company's website promoted cement use, which was not approved.

Such changes represent a major change or modification in the intended use of your device that require a new premarket notification, the FDA wrote in the letter, dated August 19.

For the TruMatch product, FDA said its records showed the company did not seek approval before selling the artificial knees and called on the company to submit an application.

The FDA will evaluate the information you submit and decide whether your product may be legally marketed, it said.

DePuy spokeswoman Jessica Masuga had no immediate comment on the letter.

The FDA released the letter on its website at

Shares of J&J were down 1.4 percent at $58.04 in morning trading.