Knee replacement cement failure may be a common issue caused by defects associated with surgical cement.

Bone cement is commonly used during knee replacement surgery to help secure the implant in place against the natural bone.

Although “cement” usually suggests that a material is used to adhere two surfaces together, but bone cement actually serves as a space filler between the natural bone and the surface of the implant. The materials reportedly rely on the close mechanical interlock between the irregular surface of the bone and the artificial surface of the implant.

The cement comes in different viscosities including low, medium, and high. Low viscosity bone cement has a long mixing phase and a short working phase, meaning that the product must be applied within the strict application recommended times. High viscosity bone cement has a shorter mixing phase with a longer working phase that allows the surgeon more time to apply.

“Ideal viscosity will be high enough to avoid any cement mixing with blood or fat/bony material from the implantation region yet low enough to penetrate the bone adequately,” according to a report in the Journal of Clinical Orthopaedics and Trauma.

Although bone cement has been used in medical settings for hundreds of years, high viscosity bone cement may be associated with knee replacement implant failure according to scientific research.

A 2015 study showed that the relatively uncommon occurrence of aseptic loosening, which is loosening of the implant in the absence of an infection, may be associated with high viscosity bone cement. The study examined total knee replacements performed between May 2005 and December 2010. In all of the cases of early failure, high viscosity cement was reportedly used with the implant – leading researchers to theorize that the properties of high viscosity bone cement may cause knee replacement cement failure.

“Properties of [high viscosity cement] may contribute to making it more susceptible to early failure in a small number of [total knee replacements],” the knee replacement cement failure study concluded. “[High viscosity cement] in total hip replacement (THR) has been associated with cement micro-fractures, cement debris generation, and early implant failure. The mechanical properties of [high viscosity cement] may similarly contribute to early failure at the cement-implant interface in a small percentage [total knee replacements].”

Although total knee replacement is a fairly routine surgery, the use of high viscosity cement may cause significant pain and reduced quality of life due to implant failure.

When a knee replacement implant fails, revision surgery is typically necessary. Revision surgery involves removing the failed implant and replacing it with a new device. Surgery can be difficult because implant failure may cause damage to the surrounding bone and tissue – making the surgeon’s job more difficult.

Additionally, revision surgery may be difficult for patients due to the complexity and trauma associated with removing an implant and re-implanting a new device in a potentially damaged area of the body.

Due to the risks associated with bone cement, more manufacturers are developing implants that rely on press-fit junctions which encourage bone growth in order to stabilize the artificial joint.