The Zimmer Persona knee replacement implant has been linked to two serious complications, which has forced numerous patients to undergo revision surgery.

Components from the affected Zimmer knee replacement models were voluntarily recalled by the company in early 2015, affecting about 12,000 implants that had already been distributed. In March of that year, the FDA announced it as a Class 2 recall, a category typically reserved for medical devices indicated to cause temporary or reversible harm to patients. The recall was for a specific component of the knee replacement system called the Persona TM tibial plate, and not the implant as a whole.

The Zimmer knee replacement consists of a metal tibial plate with two pegs, designed to be implanted into the bone without the need for cement. The tibial plate attaches to the tibia, with the two pegs meant to “grow” into the bone after being inserted into the bone.

The two pegs are supposed to give stability for the Zimmer knee replacement. This treatment mechanism is described as “biological fixation” by Zimmer, as the pegs are meant to be a natural stabilizer.

Overview of Zimmer Knee Replacement Complications

The Zimmer knee replacement recall was initiated primarily based on the injuries allegedly caused by the uncemented components of the device. The tibial plate is coated with a porous surface, which is supposed to make the uncemented biological device components connect with the bone while inside the human body.

However, X-ray images show gaps between the tibial plate and bone, which indicate “poor seating.” Radiolucent lines are also seen in injury reports, showing how the device moved away from its initial position and the implant became loose.

Patients going through Zimmer knee replacement failure may experience painful side effects including, but not limited to:

• Chronic Pain
• Mobility Loss
• Inflammation
• Knee Instability
• Knee Tightness or Stiffness
• Fracture
• Loss of Fixation
• Device Failure

These signs and symptoms may indicate the Zimmer knee replacement was either improperly implanted or potentially defectively made. According to Zimmer, 38% of patients who had the Zimmer Persona knee replacement implanted had to undergo revision surgery due to device complications.

It is important to note that revision surgery is considered riskier than the initial implant procedure, due to higher risks of blood clot damages and fracture. Bones that have already been damaged by the initial surgery could need grafting in order for the second surgery to be complete. Additional surgeries may also cause differences in the lengths of the patient’s legs.

The Zimmer knee replacement was approved by the FDA through the agency’s 510(k) approval process, which allows a medical device to bypass rigorous pre clinical testing phases typically required. As long as the medical device proves to be “substantially equivalent” to another product already on the market, then they may qualify for the FDA 510(k) program.

However, many critics have alleged this fast track approval process allowed the Zimmer knee replacement to enter the market when it really should not have. In addition, some have alleged that Zimmer either knew or should known about the alleged defective nature of the medical device.