Some knee replacement patients have recently been complaining their prostheses have been failing due to bone cement that does not properly attach the implant to the bone.

There have already been several bone cement failure lawsuits filed by patients, who allege the bone cement in their knee replacements was defective and caused the need for revision surgery. Some of the bone cements at issue may include:

• Cobalt HV Bone Cement (Biomet/DJO Surgical)
• DePuy CMW 1 Bone Cement
• Simplex HV Bone Cement (Stryker/Howmedica)
• SmartSet HV Bone Cement (DePuy)

Bone cement failure typically occurs for one of two reasons: either aseptic loosening or bone cement implantation syndrome.

Aseptic loosening is when the device moves out of place without infection, which can occur if the bone cement becomes fragmented or if the cement’s bond with the bone becomes broken. Aseptic loosening most commonly occurs where the knee replacement attaches to the tibia rather than the femur.

Overview of High Viscosity Bone Cement Complications

According to a 2016 study published in the National Center for Biotechnology Information, researchers analyzed 13 patients who allegedly experienced bone cement failure in their knee replacements. In these cases, the knee implants had become detached from the bone along the side of the front tibia.

Researchers noted that early failure in bone cement due to aseptic loosening is not common and that the purpose of this study was to look for potential causes of these failures.

Researchers analyzed 3,048 primary total knee replacement surgeries performed between May 2005 and December 2010. Nine failures were reported in eight patients, with high viscosity cement (HVC) used in all these cases.

Bone cement has been on the market since the FDA’s approval in the 1970s, primarily for hip and knee replacement surgeries. Bone cement works by relying on the closely knit mechanical interlock between the irregular bone surface and the prosthetic, with the use of any adhesives.

There are three types of bone cement that are utilized from low, medium, to high viscosity levels, categorized by how long the cement takes to set. Low viscosity level cement consists of a long waiting period for the liquid mixing phase, which results in a short working phase. This means orthopedic surgeons must apply the cement at strict application times.

In contrast, high viscosity cement has a short mixing phase and does not stay adhesive for very long. While this does give the surgeon more time to apply the cement, the ideal viscosity level should be high enough to prevent blood and cement mixing but low enough to sufficiently adhere to the bone.

Furthermore, it has been alleged that high viscosity cement is more likely to lead to cases of bone cement failure. Researchers state that this may be due to the cement not properly bonding to the bone, which can cause cement micro fractures, cement debris degeneration, and premature device failure.

Patients who received knee replacement prostheses with bone cement should be wary of any painful symptoms including

• Sudden and persistent chronic pain
• Instability
• Knee implant loosening (aseptic loosening)
• Swelling
• Limited range of motion

Patients who experience these symptoms should speak to their doctors immediately, as sometimes the bone cement toxins can cause serious biological reactions including:

• Low oxygen levels
• Low blood pressure
• Unexpected loss of consciousness
• Blood clots
• Cardiac arrest
• Death