What is Bone Cement?
Bone cement is an epoxy cement used to attach the components of a knee implant to human bone during a total knee replacement.
What is a Total Knee Replacement?
Total knee replacements (TKRs) are the most common knee surgery, and are designed to help patients regain quality of life. People who are candidates for TKR are those with severe destruction of the knee joint along with progressive pain and impaired function. Osteoarthritis is the most common reason these surgeries are performed.
According to the Academy of Orthopedic Surgeons, 90 percent of people who undergo TKR experience less pain and, in most cases, are able to perform daily activities, even resuming activities like golf and walking that their arthritic pain made them give up years ago. Due to the high success rate of TKR, the Arthritis Foundation estimates the number of procedures will exceed 3 million by 2030.
However, some patients who undergo TKR experience problems that in some cases could have been prevented.
Bone Cement Complications
The increasing demand for total knee replacement surgery has forced the medical community to consider alternative products that will increase operational efficiency, including relying more heavily on a type of bone cement known as high-viscosity cement (HVC).
During total knee replacement, the damaged knee joint is removed and replaced with prosthesis of metal, ceramic and/or plastic components. Doctors attach the components of the new knee joint to the femur (thigh bone) and tibia (shin bone), using an epoxy cement. This bone cement comes in two separate components – a powder and a liquid that have to be mixed together. High-viscosity cement (HVC) offers a shorter mixing and waiting time and longer working and hardening phases. These shorter times mean that surgeons can handle and apply the cement earlier than with low- or medium-viscosity cements.
Although high-viscosity cement may be more convenient to use, there is mounting evidence that the bond it produces is not as strong. Researchers have observed more early failures with the use of high-viscosity bone cement, even when used in combination with a previously well-performing implant.
A 2016 case series by the National Center for Biotechnology Information (NCBI) evaluated 13 cases of tibial component debonding (where the implant fails to adhere to the cement interface on the shin bone) in implants performed with high-viscosity cement. The study’s authors advised surgeons to be aware of the possibility of debonding of the tibial component when using HVC, after finding no instances of aseptic loosening or tibial component debonding in cases using the same implant and non-high-viscosity cement.
An earlier study found only nine early failures out of more than 3,000 total knee replacements. All of the failures involved high-viscosity cement. Additionally, the Orthopaedic Research Society has found that researchers deem HVC less effective than low- or medium-viscosity bone cement.
Bone Cement Side Effects
Patients who have a bone cement failure experience symptoms often require revision surgery to remove and replace the device. Symptoms of bone cement failure are similar to when a knee replacement system fails, and include:
- Implant loosening and debonding
- Unusual swelling at the joint site
- Decreased range of motion
- Persistent pain
- New chronic pain
- Pulmonary embolism
- Bone cement Implantation syndrome
What is Bone Cement Implantation Syndrome?
Bone cement implantation syndrome is a rare and poorly understood complication that occurs when bones spontaneously release fat and marrow into the bloodstream after bone cement is injected during a total knee replacement. This can lead to serious complications including blood clots in the lungs (pulmonary embolism), cardiac arrest, and death. Long-term side effects of bone cement implantation syndrome include low oxygen (hypoxia) and confusion.
Approval of Bone Cement
Manufacturers of bone cement enhanced the push to gain clearance from the Food and Drug Administration (FDA), claiming it was “substantially equivalent” to epoxies on the market, which allowed high-viscosity cement to be cleared under the FDA’s fast-track approval process. This process does not require products to demonstrate their safety and efficacy.
Bone Cement Lawyer
Lawyers in Beasley Allen’s Mass Torts Section are currently investigating cases involving early knee implant failure associated with high-viscosity bone cement. If you or a loved one has experienced complications from knee replacement surgery (including new onset chronic pain, instability, or loosening or debonding of the tibial component) contact us by filling out the form on this page.