Artificial knee implants are created to be very strong, flexible and last the test of time. Most patients who have had knee replacement surgery are the beneficiaries of well designed and manufactured products. Each year over 200,000 knee replacement surgeries are performed in the United States. Recent studies suggest 90% of patients report an improvement in overall health-related quality of life and an amazing 85% of patients reporting they are satisfied with their surgery.
The most common problem encountered by individuals who have had knee replacement surgery is component loosening which can occur for a wide variety of reasons.
A knee implant is made up of three main parts or components:
- Femoral component: This part is at the top of the implant and made of metal. It attaches to, and replaces the bottom portion of the femur, where the kneecap attaches.
- Patellar component/Articulating Surface: This is generally made of polyethylene plastic and acts as the kneecap. It replaces the patella, which glides over the femur.
- Tibial component: This is the bottom portion of the implant and is comprised of plastic and metal materials. It is attaches to the top portion of the tibia, or shinbone. The device is made up of two parts, a metal tray that is attached to the bone, and a plastic portion (spacer) that provides a smooth surface.
On September 13, 2010 it was announced that certain tibial components used in the Zimmer NexGen MIS were recalled. Not all Zimmer NexGen knee implants were involved in the recall. The recall involves an estimated 68,000 components used worldwide. The exact number of these 68,000 components used in patients in the United States is unknown.
On April 26, 2010, Zimmer, Inc., one of the largest manufacturers of orthopedic devices in the world, sent a letter to consumers informing medical professionals that a modified surgical technique should be used in implanting the NexGen MIS. Reports indicated that over 100 individuals with this device reported early loosening requiring revision surgery.
In addition to the September 13, 2010 recall, there are concerns that a recent study suggests the NexGen CR-Flex Porous Femoral component is also experiencing an abnormally high failure rate. In the summer of 2010, Dr. Richard A. Berger an orthopedic surgeon and former Zimmer employee released findings indicating a high early-failure rate for the CR-Flex Porous component. Zimmer had indicated they believe the study to be flawed and the findings to be contrary to that of other studies and the component has not been recalled.
Available for use in the United States since 2005, the NexGen CR-Flex Porous Femoral component seeks to replace the use of adhesives to attach the femoral component to the patient’s femur. The CR-Flex is designed to allow the bone to graft directly to the prosthetic.
Dr. Berger and others are concerned that the CR-Flex Porous components fail to properly and completely fuse to the femur resulting in loosening and early device failure.
If you have a Zimmer NexGen knee prosthesis that has required repair or replacement surgery or would like to determine if your knee implant is included in the September 13, 2010 recall, please contact Loncar Lyon Jenkins at 800-285-HURT or by completing the “Do I have a Case” form below.
You should be aware that the recall creates certain legal deadlines on the part of patients affected by the recall. Failure to meet these deadlines can prevent injured patients from receiving compensation in the event of a device failure requiring repair or replacement surgery of the failed component.