Zimmer Persona knee failure has been linked to the tibial plate component used in a total knee arthroplasty (TKA). According to the American Academy of Orthopaedic Surgeons, a TKA is—for the most part—a medical success story repeated at least 600,000 times a year in the U.S. alone.

When a prosthetic knee joint used in this procedure ceases to function prematurely—as in the case of Zimmer Persona knee failure–the additional risks a patient undertakes to have it removed and replaced are significant and worrisome. First, let’s explore the process of a TKA and what parts comprise a functioning prosthetic knee joint.

What is a TKA?

While there is no set age at which a TKA is done, it is generally undertaken when all options for relieving the pain of knee arthritis have been exhausted such as cortisone or lubricating injections, physical therapy, and use of anti-inflammatory medications.

The typical age range is 50-80, but it has been done in younger patients, particularly if the patient suffers from post-traumatic arthritis that developed after a significant injury to the joint. Other types of arthritis include osteoarthritis typically associated with the wear and tear of aging and rheumatoid arthritis which is a very damaging inflammatory condition affecting the knee.

In a TKA, the end of the femur or upper thigh bone and the top of the tibia or lower leg bone are removed where they join together to remove damaged surface area and cartilage after knee surgery.

Metal parts which mimic the real joint are implanted and include a tibial component with one or two stabilizing pegs, a femoral component, and a plastic spacer. The underside of the natural knee cap is resurfaced in some cases to glide more smoothly over the prosthetic unit.

Zimmer Persona Knee Failure and Component Recall

According to the U.S. Food and Drug Administration (FDA), the Zimmer Company initiated a voluntary recall of the Persona Trabecular Metal (TM) tibial plate toward the end of January 2015. The recall affected 11,658 units and was said by the company to be because of a growing number of complaints regarding radiolucent lines and loosening.

Radiolucent lines as they appear on an X-ray are gaps between the tibial implant and the bone into which it was implanted. These lines may represent gaps created by the component loosening or moving from its original position. In the case of the Zimmer Persona TM tibial plate, the two pegs which stabilize the plate are expected to grow into the bone after surgery and are not cemented.

The loosening of this component could be experienced as chronic pain, inflammation, and a sense of joint instability. For many TKA patients implanted with a Persona knee, these experiences eventually demanded that they undertake revision knee surgery in which the prosthetic is removed and replaced with alternative parts.

This surgery, according to Johns Hopkins Medicine, may pose additional risks such as nerve or blood vessel damage. In the event of such damage, knee pain may not be relieved surgically. Leg length discrepancies due to some knee bone tissue loss is also common in knee revision.