Zimmer NexGen CR-Flex Knee System

Zimmer NexGen CR-Flex System is part of the Next Generation line which was intended to be more flexible for a younger patient and to offer greater range of motion for a more diverse population who may be required to spend time in kneeling or other positions. Unfortunately, the line has resulted in some higher than expected failure rates and a need for revision surgery.

zimmer cr-flexZimmer specializes in developing and manufacturing personalized joint replacements for consumers. Zimmer was among the first companies to play a role in the popularization of knee replacements, or knee arthroplasty. It developed its first total knee replacement device in 1968. Zimmer has grown to become one of the leading companies in this market. It is estimated that Zimmer generates roughly $4 billion in sales each year.

While it has found great success in this market, Zimmer also faces issues from defective devices. A number of patients are filing claims against the company for products such as the Zimmer NexGen CR-Flex knee replacement system. Patients experienced a number of debilitating side effects such as severe pain, infection, bone fracture, and failure of the Zimmer NexGen CR-Flex device. Many patients are forced to undergo revision surgery to correct problems caused by the Zimmer NexGen CR-Flex system.

NexGen CR-Flex FDA Approval

The Zimmer NexGen CR-Flex system was approved using the 510(k) Premarket Notification process. Through this process, drugs and devices may receive expedited approval if the manufacturer can prove a significant similarity to a product that has already received FDA approval. As a result, the 510(k) process allows for the approval of products which are not yet backed with extensive clinical testing. This means that manufacturers and the FDA become aware of specific product issues only after it has been approved and used by consumers.

Zimmer motioned that the NexGen CR-Flex system was similar to the original NexGen knee replacement product line. This system received FDA approval in 1994. However, the NexGen CR-Flex system is significantly different in that it does not use fixative or cement to attach the components. Instead, the system uses the NexGen CR-Flex Porous Femoral Component.

This component is coated with a porous liner that caps the thigh bone’s connection with the tibia. The porous liner helps to encourage osseointegration, or bone growth. It also eliminates the use of cement, which may pollute nearby tissue and enter the bloodstream. While the Zimmer NexGen CR-Flex is beneficial for preventing these issues, many patients have experienced loosening due to incomplete fusion.

NexGen CR-Flex Study

The lack of cement in the Zimmer NexGen CR-Flex line has created issues for both surgeons and patients. In 2010, doctors from the Rush University Medical Center in Chicago presented their study results at the American Academy of Orthopedic Surgeons conference. The study discussed the failure rate of high-flex total knee replacements.

In the presentation, the team primarily discussed the Zimmer NexGen CR-Flex system. It noted that more than nine percent of patients who received a NexGen CR-Flex implant required revision surgery due to device loosening and associated pain. Additionally, the study revealed that 36 percent of the 108 participants experienced loosening of the device’s porous femoral component. Researchers observed that this failure rate was not related to the surgeon, surgical approach, or patient type.

NexGen CR-Flex Controversy

One of the main researchers behind the Rush University was Dr. Richard Berger. Nearly a decade prior, Berger was a paid consultant for Zimmer. During his time working with Zimmer, Berger was paid more than $8 million for his services. By 2005, Berger implanted the Zimmer CR-Flex knee system in 125 patients. Within a year of implantation, Berger reported to Zimmer that a number of his patients experienced loosening and severe pain caused by failure of the femoral component to properly fuse to the patients’ bone. Berger stopped using the product by 2005.

Zimmer continued to support the NexGen CR-Flex device. The company insisted that surgical techniques and procedures were responsible for the device failure. In June 2010, the New York Times published an article that discussed the dispute between Berger and Zimmer. This brought Zimmer’s public relations issue into the national spotlight.

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