Zimmer Holdings Inc. designed its NexGen Tibial Component to be used in minimally invasive surgery (MIS) to replace the tibia, or shinbone, the larger of the two bones that extends from the knee to the ankle.
MIS surgical procedures use a smaller incision for insertion of the device so that less muscle and tendon is cut.
Two important design features of the Zimmer Tibial Component were:
A 45-mm or 75-mm Drop Down Stem Extension that allowed the surgeon to make the stem implant longer after it had already been placed in the bone marrow canal inside the tibia. The ability to lengthen the extension meant a better fit if the canal was misshapen because of disease or injury.
A shorter, broader keel that locked into the part of the bone that was the densest. The keel is made up of the fins on either side of the implant that helps it stay fixed and in the bone. Locking into the densest part of the bone meant that the surgeon didn’t have to cement the implant in place, eliminating the problem of cement interfering with knee function.
Complications with the Zimmer NexGen MIS Tibial Component
In September 2010, Zimmer recalled the Tibial Component after 114 Medical Device Reportings (MDRs) said the implant became loose and patients required revision surgery to remove it. There were 68,384 of these products distributed worldwide, but there was no clear indication of how many of them had been implanted into patients.
Zimmer sent an Urgent Device Correction letter to surgeons in April 2010 advising them to:
- Achieve adequate visualization and access if an MIS approach is used. An inherent problem with the MIS technique is that a smaller incision means that surgeon’s view may be restricted when inserting the implant, meaning that the device may not be placed in the optimal position, causing a higher failure rate.
- Use a drop-down stem extension with the NexGen MIS Tibial Component.
- Cement fully and pressurize the anterior and posterior surfaces of the tibial component.
- Carefully use bone cement application per the manufacturer’s instructions
Surgeons were also instructed to destroy or disregard previous versions of surgical technique that Zimmer had issued regarding the implantation of the Tibial Component, and to familiarize themselves with the new materials describing surgical technique that accompanied the device correction so that they could be aware of changes and warnings.
Lawsuits Related to the NexGen MIS Tibial Component
A Judicial Panel on Multidistrict Litigation in August 2011 transferred 18 lawsuits filed against various Zimmer NexGen Knee Replacement products, including the Tibial Component, to the U.S. District Court for the Northern District of Illinois. An additional lawsuits were already pending in that Court, bringing the total of cases pending to 28.
However, from August to the beginning of October, 62 additional cases were also transferred. Then, in October 2011, a provisional transfer order was issued for three additional cases.
According to the original transfer order, all of the components in question are prone to loosening, leading to causing pain, immobility and often revision surgery. Zimmer failed to persuade the court to stop the consolidation.