Medtronic Inc., which has been defending Infuse bone graft lawsuits, is now facing class action lawsuits filed by its own shareholders over its handling of the controversial medical device.

Two distinct class action lawsuits have been filed against Medtronic by shareholders. Medtronic is seeking to dismiss the shareholders’ lawsuits on the grounds that the claims have no merit or legal basis.

Medtronic shareholders claim the medical supply company under-reported and misled shareholders about the severity and extent of side effects associated with implantation of the Medtronic Infuse bone graft, used in the surgeries of thousands of patients across the United States. By refusing to disclose the extent and nature of all Infuse bone graft side effects, shareholders allege that Medtronic has violated U.S. Food and Drug Administration (FDA) marketing regulations with the sole purpose of boosting Infuse sales.

These shareholders’ lawsuits come on the heels of last month’s Infuse lawsuit brought against Medtronic by the national healthcare provider Humana. Humana alleges that Medtronic paid off researchers and doctors to overstate the efficacy and safety of the Infuse bone grafts, while making the potential Infuse side effects — including sterility, nerve damage, and increased risk of cancer — seem negligible and rare.

Medtronic has already paid out $22 million in legal settlements in Infuse bone graft lawsuits in the face of allegations of unwanted and unreported side effects from Infuse bone graft patients and their healthcare providers.

Background  on Infuse Bone Graft

The Infuse bone graft is produced from synthetic proteins mixed with bovine collagen and is used in spinal fusion surgeries to alleviate pain and encourage bone growth. The Infuse bone grafts are designed to replace damaged material in various joints and bones.

More than 100,000 patients a year have received Medtronic Infuse bone grafts during spinal fusion procedures since FDA approval in 2002. As a result, Medtronic generated revenue of $900 million in the 2011 sales year alone. Medtronic is the current leader in the bone graft market, accounting for more than 40 percent of all bone graft sales in the United States.

However, Medtronic allegedly failed to inform hospitals, physicians, and individuals of all the possible health risks associated with the Infuse bone graft system, including:

• Infection
• Male sterility
• Bone and nerve damage
• Urinary problems
• Increased risk of cancer