Patients suffering from NexGen knee failure problems are filing Zimmer NexGen knee lawsuit claims to help compensate for outstanding medical bills and the pain and suffering associated with having additional surgeries. Surgical cement has been used to implant knee replacements for more than fifty years. Over that time, it has proven to be an effective method of fixation. Cementless (often called “press-fit”) implantation is a more recent development. It has been used increasingly over the past twenty years. The Zimmer knee recall issued by the FDA in September 2010 addressed the tibial plate, a component designed to be fixated with or without bone cement. We’ll describe the key issues concerning both methods of implantation below.

Fixating The Prosthesis With Surgical Cement

Bone cement was originally used in total knee arthroplasty as a substitute for ligaments (i.e. bands of connective tissue). The knee joint relies on four ligaments to keep the bones in place: the anterior and posterior cruciate ligaments, and the lateral and medial collateral ligaments. During knee arthroplasty, one or more of these ligaments may need to be removed. Bone cement is used to hold the implant in place.

The cement is applied between the surfaces of the tibia and femur, and the tibial and femoral components (respectively). Even though the bones need to be shaped prior to receiving the prosthesis, the cement is forgiving of irregularities on both surfaces. Once applied, the material hardens quickly. It can support the patient’s weight on the same day of the procedure.

One of the issues with cemented fixation is that the cement may begin to break apart due to load and wear. Small pieces may separate from the implant, contaminating nearby tissue.

Another potential problem is that the tibial component may sink into the top of the tibia. This occurs because the hard, bony surface of the tibia is removed prior to implantation of the tibial piece. Underneath the hard bone lies softer bone. Over time, the weight placed on the knee can cause the tibial plate to sink into it. Because the load is often distributed unevenly, this can lead to loosening of the prosthesis.

To clarify, this problem can occur with cemented and cementless knee replacements. In the former case, the cement acts as a mild buffer.

Implanting The Zimmer Knee Replacement Without Cement

Cementless fixation of the tibial and femoral components is less common than cemented fixation. The method requires the patient to have healthy bone stock, which is often an obstacle for older recipients. The implant is designed with a porous, textured contact surface. The tibia and femur grow into this surface, fusing with it.

This form of implantation is as stable as using cement. Once the patient’s bone has grown into the prosthesis, it can be expected to hold the tibial and femoral components in place. Data show that a knee replacement that has been implanted without cement will usually last as long as one implanted with it.

One of the drawbacks of cementless implantation is that the bone may become less stable as the result of debris that flakes off from the prosthesis. This debris is generated by friction. Whenever the patient moves her knee, the cobalt-chromium components rub against the polyethylene spacer that sits atop of the tibial plate. This generates particulate matter, which can cause inflammation in the joint, and eventually harm the bone.

While this problem can also occur with cemented fixation, it has a greater impact here. Debris, along with the body’s immune system, can create a situation that compromises the bony ingrowth that holds the prosthesis in place. If this occurs, the implant will loosen. This is one of the complications that prompted the FDA’s Zimmer knee recall of the tibial plate in 2010.

Zimmer NexGen Knee Lawsuit
The issues that plague the recalled tibial component of the NexGen knee replacement are believed to also affect the femoral component. This is the reason many experienced orthopedic surgeons have urged the manufacturer to announce a broader Zimmer knee recall. If you are experiencing knee pain, joint loosening, or other serious NexGen knee failure side effects, you may be able to file a claim for compensation. Contact a Zimmer lawsuit knee attorney to learn more about your options. We are currently filing individual lawsuits on behalf of patients and there is not national Zimmer class action lawsuit covering all cases.

Patients suffering from a defective Zimmer NexGen have started filing individual lawsuits and there is no national Zimmer class action lawsuit covering all cases. Orthopedic surgeons warn patients receiving knee implants that their prostheses can be expected to loosen after fifteen years. This problem can occur for a number of reasons, including infection, bone deterioration and resorption, and most commonly, mechanical failures. The CR-Flex knee implant manufactured by Zimmer Orthopaedics has been known to loosen much earlier – often, within two years of implantation. This is one of the reasons prominent orthopedists have urged the joint manufacturer to announce a wide-scale Zimmer knee recall.

Premature loosening is a serious complication with total knee arthroplasty. Not only does it cause immediate pain in the compromised joint, but it also accelerates the breakdown of the patient’s bone stock. Below, we’ll describe the symptoms of knee implant loosening, and highlight the factors that play a role.

Signs Of Premature Loosening Of The Prosthesis

If the tibial or femoral component of your NexGen CR-Flex implant becomes loose, you will experience one or more side effects. The severity of the symptoms is determined by the amount of loosening in the joint. Patients in whom the prosthesis has just begun to shift may feel minor stiffness in the knee. This stiffness will usually persist throughout the day.

Recipients with knee implants that have sustained extensive loosening will encounter more intense pain. This pain will begin in the site of implantation, but spread into the surrounding area as loosening becomes progressively worse. Some patients may have difficulty moving and placing their entire weight on the failing prostheses. Many develop a pronounced limp due to the discomfort that accompanies walking.

If you suspect that your Zimmer knee implant has become loose, ask your doctor to take x-rays of the joint. The images will reveal spaces between the bone and the tibial or femoral components. These spaces will often fill with connective tissue.

What Causes Loosening In The Zimmer Knee Implant?

There are many possible reasons your NexGen knee replacement can loosen prematurely. Earlier, we mentioned the bone of the joint may deteriorate or experience resorption. In the former case, a loose tibial or femoral piece can damage the surface of the tibia or femur (respectively). Sometimes, tiny fractures will form, causing the joint to becomes less stable.

With resorption, the bone to which the prosthesis is attached breaks down due to exposure to foreign particles. These particles flake off from the tibial and femoral components as well as the polyethylene spacer. The body attempts to “clean” the area of this foreign debris by initiating an autoimmune response. This response causes resorption.

It is also noteworthy that the Food and Drug Administration (FDA) issued a Class 2 Zimmer knee recall in September 2010. The recall was announced due to complaints of premature loosening in the NexGen tibial plate. This component was originally designed to be implanted with or without surgical cement. However, five months prior to the FDA’s Zimmer NexGen recall, the joint manufacturer sent a letter to orthopedists, warning that they should only implant the tibial plate with cement. This warning suggests the component may have been defective.

When Does Revision Knee Surgery Become Necessary?

A knee replacement that loosens will eventually need to be replaced. The problem will continue to worsen, causing increasing pain and reduced mobility. Unfortunately, revision surgery is often problematic due to the deterioration in the patient’s bone stock. The compromised tibia or femur (or both) is less capable of holding the replacement prosthesis in place.

For this reason, orthopedic surgeons usually urge their patients to wait until the pain becomes unbearable before undergoing revision surgery. The longevity of the replacement knee implant is rarely as good as the original.

The failure rate of the Zimmer NexGen CR-Flex is estimated at 9 percent, far higher than comparable knee replacements. Loosening, pain, and dislocation are the most serious complications stemming from a defective implant. If you are currently suffering from knee pain, swelling, looseness of the joint, or other serious Zimmer knee side effects, you may be due compensation for your injuries. Contact a Zimmer knee replacement recall lawyer to discuss your legal options.