Bone Cement – Application & Health Benefits
Bone cement
Bone cement is a two- component adhesive , which is created quickly before use by mixing a powder with a liquid. It is used for the elastic anchoring of artificial endoprostheses to the bones . After inserting the implants , the artificial joints can immediately bear normal loads again thanks to the properties of the bone cement.
What is bone cement?
Bone cement is an adhesive that can firmly and elastically connect artificial endoprostheses to the joint. It is a polymer of methyl methacrylate. Methyl methacrylate or PMMA is a widely used material, also known as Plexiglas. PMMA connects two materials very firmly and is also very elastic at the same time. Precisely these properties predestine this adhesive for the stable bonding of components that are exposed to constant mechanical stress. This applies in particular to artificial joints.
Apart from the exhaustion caused by the operation, the patient can fully bear weight immediately after inserting the implant, since the material has a high level of elasticity in addition to its high binding capacity. However, changing the implant can be difficult because the bone cement is difficult to remove.
Bone cement has been used successfully for the insertion of artificial joints since the middle of the 20th century. This applies to all joints such as knee joint, hip joint, elbow joint or shoulder joint. Bone cement is now routinely used because it is convenient and easy to use in clinical practice.
Shapes, Species & Types
Bone cement is a uniform material, which is a polymer of methyl methacrylate. It is formed by an exothermic polymerization reaction after mixing together two components called binder and hardener. It is a powder and a liquid. The liquid consists of a solution of the monomer, while the powder contains the activating substance.
The polymerization proceeds with evolution of heat. After mixing the two components, a doughy paste is created, which transforms into an elastic, glass-like substance. This substance represents the actual bone cement.
The only differences in the composition of the bone cement are the addition of antibiotics such as gentamicin to prevent local infections at the surgical site. The addition of antibiotics is individually adjusted.
Furthermore, the bone cement also contains different proportions of so-called contrast media in order to be able to display them in imaging procedures such as X-ray examinations. Barium sulfate or zirconium dioxide , among others, are used as contrast media .
Structure & functionality
During the operation, the bone cement is mixed by mixing powder and liquid. A doughy mass is created with heat development, which is filled into the bones. All cavities are mixed with this mass and thus sealed. The prosthesis is then carefully embedded in this doughy substance. There is an increasing increase in viscosity, with the cement mass hardening and forming a matrix. This permanently fixes the artificial joint. The cement is still flexible enough to ensure the mechanical load capacity of the prosthesis.
The heat of reaction during cement formation can increase to 70 degrees Celsius. However, the organism can only tolerate a maximum temperature of 42 to 46 degrees Celsius. Above this temperature there is a denaturation of body proteins . To ensure this low temperature, the surgical procedure must be so precise that it is possible to use very thin layers of bone cement. With a layer of less than five millimeters, the heat dissipation is sufficient due to the larger surface to protect the surrounding tissue . Heat dissipation also takes place via the large surface of the prosthesis and via the blood flow .
Medical & health benefits
The use of bone cement has proven to be very successful in clinical practice. Patients can be quickly remobilized after the operation. The prosthesis can quickly be fully loaded. The material is very stable and durable, so the long-term results are very good. The mechanical resilience is also very high right from the start due to the elasticity of the bone cement.
Another advantage is that before the components are mixed, antibiotics can be added to the powder, which effectively prevent infections at the surgical site. After the operation, these active ingredients are slowly released and thus exert a local influence. The release is so low that local antibiotic effectiveness is guaranteed, but the entire organism is not burdened with antibiotics. Joint surgery should only be performed without the use of bone cement if there is a known allergy to antibiotics.
In rare cases, the operation can lead to a drop in blood pressure and oxygen saturation. A vasodilating effect of the cement due to the formation of gases during polymerisation is being discussed. Overall, the use of bone cement is part of medical routine due to its high success rate.
However, when a prosthesis needs to be replaced, bone cement often proves stubborn. If there is no infection, the cement does not have to be completely removed. In the event of an infection, however, a radical replacement of the bone cement is necessary. However, according to the knowledge available today, it is easier to remove cement than to replace cementless prostheses that have grown well into the bone bed.
Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.