Loosening and Faulty Knee Implants

When a knee device fails — by not performing as designed — unsuspecting people are subjected to painful complications. Knee device failure can be the result of a patient being obese or performing excessive high-impact activities. Sometimes, the device fails because of the manufacturer’s faulty design. The Food and Drug Administration’s 510(k) premarket program allows manufacturers to release knee implants without testing as long as they are similar to products already on the market. Unfortunately, many patients and their doctors are unaware of device problems until after they have already been implanted. Complications resulting from a device are tracked by the FDA and labeled as “adverse events.” These complications often result in the need for revision surgery to replace the problematic device.

Loosening is one of the most common complications resulting from a faulty device. This occurs when components of an implant begin to separate from the bone. Soft tissue instead of bone can grow in between the components and the bones, creating instability and pain in the joint. Loosening is natural over time, but it usually does not occur for several years. In poorly designed devices, it can occur in a year or less. Some manufacturers like Zimmer Holdings have blamed the device failure on the surgeons despite the fact that some of their models show higher than normal revision surgery rates regardless of the surgeon who implanted them. Thousands of people have had Zimmer’s NexGen Knee models implanted since 2002. According to the FDA, there have been hundreds of adverse events resulting from Zimmer’s devices.

Zimmer’s NexGen CR-Flex uncemented knee was designed to encourage the patient’s bone to grow and naturally fuse with the device. Instead, in just a year, the components can loosen and cause a patient severe discomfort and pain. One doctor reported that the loosening occurred in 36 percent of patients who had received the knee implant.