Zimmer’s Persona trabecular metal tibial plate has been linked to device failure in Persona knee implants, which forced some patients to undergo revision surgery.

The Persona trabecular metal tibial plate has been linked to device loosening and radiolucent lines, which can drastically increase the risk of device failure. The Persona trabecular metal tibial plate is a metal component of the Zimmer Persona knee implant, which is a knee prosthetic implant that does not use cement.

The Zimmer Persona knee implant is directly implanted into the tibia, using two pegs that are directly inserted into the bone and are supposed to “grow” into the bone. The pegs are meant to give the implant stability and simulate natural bone growth and movement.

There are approximately 4.4 million total knee replacement patients, who have used implants like the Persona system to restore knee function in damaged or deteriorated knee bones. A significant portion of these knee implants involve the Persona trabecular metal tibial plate, which has been the subject of numerous injury reports and two market recalls.

Overview of Persona Knee Implant Complications

Zimmer had issued a voluntary recall of certain Persona knee implants in February 2015, with the recall affecting nearly 12,000 Persona trabecular metal tibial plate. Zimmer had issued the recall after injury reports indicate two major complications:

• Radiolucent Lines: X-ray images show gaps between the Persona trabecular metal tibial plate and the bone, which indicates “poor seating.” Poor seating occurs when the device is not properly implanted and moves out of position soon after the surgery. Radiolucent lines are one of the first signs of device loosening.
• Loosening: The Persona trabecular metal tibial plate becomes dislodged from its original implant location, which “is one of the most prevalent causes for revision in total knee arthroplasty” according to Zimmer.

The FDA announced this recall in March 2015, with the agency classifying the move as a “Class 2 Recall.” This type of recall is designated for drugs and devices that have been linked to temporary or reversible harm. The FDA recall affects all sizes and lots of the Persona trabecular metal tibial plate.

The Persona knee implant was approved in 2012, to be an option for patients needing a knee replacement implant. The device was approved through the FDA’s 510(k) program, which allowed the device to bypass the rigorous testing phase typically required by the agency.

A new device that the manufacturer can show is “substantially similar” to another device already on the market may qualify for the 510(k) plan. Many consumer advocates complain this program has allowed unreasonably dangerous drugs or medical devices to enter the market.

The Persona trabecular metal tibial plate has reportedly caused 38% of patients to develop radiolucent lines, some of whom had to undergo revision surgery to fix these knee implant complications. It is important to note that revision surgery is considered even riskier than the initial implant procedure, because of higher risk of infection.

Even though the recalls may prevent future incidents involving the Persona trabecular metal tibial plate, it does not already help patients who have already sustained injuries. Many of these injured patients may be in a position to file legal action against Zimmer for allegedly failing to warn them against these problems.