By Susan Kelly

June 2 (Reuters) - Managed care company Humana Inc has filed a lawsuit against Medtronic Inc accusing the medical device maker of falsely representing its Infuse bone growth-stimulation product as safe and effective in spinal fusion surgeries.

The suit, filed on Friday in federal court in Tennessee, alleges that Medtronic paid for academic literature that fraudulently portrayed the product as safe and effective for uses not approved by the U.S. Food and Drug Administration.

Humana said it paid for the use of Infuse, a bioengineered bone protein, when less expensive and more medically sound alternative procedures were available.

It said Medtronic engaged in a "sophisticated and deeply deceptive marketing strategy" to expand the market for Infuse, paying and encouraging spine surgeons to use the product by overstating its benefits while minimizing serious risks.

Medtronic, in a separate statement, said the product's label has reflected its risks from the time of FDA approval in 2002.

"Medtronic strongly believes that the safety profile reported to the FDA and detailed in product labeling support the continued safe use of Infuse Bone Graft for approved indications," the company said.

Medtronic also said it "vigorously disagrees with any suggestion that the company improperly influenced peer-reviewed published manuscripts."

Physicians are compensated for intellectual property rights and for legitimate and documented consulting services provided to the company, Medtronic said.

Independent reviews of the product initiated by Medtronic last year determined that Infuse works as well as traditional bone grafts taken from patients, but may not be as safe.

The reviews were prompted by questions raised by spine experts and U.S. lawmakers about the safety of the product, which contains a genetically engineered protein known recombinant human bone morphogenetic protein 2 to promote bone growth.

Infuse was once hailed as a major advance in spinal fusion surgery, offering an alternative to painful bone harvesting from other parts of the body to perform a bone graft.

But in 2011, Infuse became the subject of investigations by the U.S. Senate and Department of Justice over off-label use of the product and omissions of safety problems from its clinical trial data.

The product also drew intense public scrutiny after the influential Spine Journal ran an entire issue criticizing it in June 2011, charging that surgeons who were paid tens of millions of dollars by Medtronic failed to report serious complications such as male sterility, increased risk of cancer, infections, pain and bone dissolution.

(Reporting by Susan Kelly in Chicago; Editing by Eric Walsh)