Why is PMMA used for bone cement?
In reality, “cement” is a misnomer because, the word cement is used to describe a substance that bonds two things together. However, PMMA acts as a space-filler that creates a tight space which holds the implant against the bone and thus acts as a ‘grout’.
What is the properties of bone cement?
Short-term proper- ties show that bone cement is weak in tension and strong in compression. Long-term properties (creep, stress re- laxation and fatigue) are considered in more detail as they can significantly affect the transmission of load into bone over the expected life of a total hip arthroplasty.
What is bone cement made of?
Bone cement is primarily made up of Poly(methyl methacrylate), also known as PMMA. It’s an acrylic glass that has been used in a variety of products, including some types of Plexiglas.
What is polymethylmethacrylate bone cement?
Bone cement, or polymethylmethacrylate (PMMA), has been used in surgical fixation of artificial joints for over 50 years. The primary function of bone cement is to transfer forces from bone to prosthesis.
How long does bone cement take to harden?
The calcium phosphate cement flows into the spongy inside portion of the bone, filling in microfractures and other damaged areas, and it hardens in about 10 minutes’ time, said Dr. Kelton Vasileff, an orthopedic surgeon at the university’s Wexner Medical Center.
Can bone cement be removed?
As described in “Methods of Removing Excess Bone Cement”, excess bone cement is typically removed by various techniques including cutting, scraping, and “thumbing”.
Where is bone cement used?
Bone cements have been used very successfully to anchor artificial joints (hip joints, knee joints, shoulder and elbow joints) for more than half a century. Artificial joints (referred to as prostheses) are anchored with bone cement.
How long does bone cement take to set?
Can bone cement fail?
The potential role of high-viscosity bone cement. There may be “aseptic loosening” or “aseptic tibial loosening,” which is “is the failure of the bond between an implant and bone in the absence of infection.” This could be a failure of the bone cement to do its job adequately.
Is bone cement stronger than bone?
Your bones, pound for pound, are 4 times stronger than concrete.
How long does vertebroplasty cement last?
Typically, patients resume normal activity within 24 hours. Vertebroplasty resolves pain, stabilizes fractures, increases functional abilities, and reduces spinal deformity without surgery or prolonged recovery.
What is the success rate of vertebroplasty?
The success rate for this procedure in treating osteoporotic fractures is 73 to 90 percent. Vertebroplasty can effectively treat aggressive hemangiomas of the vertebral body and may be palliative in patients with malignant pathologic fractures. Significant complications of the procedure are less than 1 percent.
What is the purpose of PMMA bone cement?
This guidance document was developed as a special control guidance to support the reclassification of PMMA bone cement into class II. The device, as classified, is intended for use in arthroplastic procedures of the hip, knee, and other joints for the fixation of polymer or metallic prosthetic implants to living bone.
What are the mechanical properties of cured PMMA?
Like bone, cured PMMA is strongest in compression and weakest in tension and under shear stress. PMMA has viscoelastic properties, exhibiting greater stiffness at higher strain rates. Its mechanical properties lie between those of cancellous and cortical bone.
What’s the difference between PMMA and cortical bone?
PMMA has a compressive strength between 85 and 110 MPa, compared with 133 to 193 MPa for cortical bone. The tensile strength of commercial PMMA and cortical bone are 30 to 50 MPa 11 and 51 to 133 MPa, respectively. 12–14 Fatigue strength, creep, and stress relaxation may be more relevant than tensile strength to long-term clinical performance.
What kind of cement is used for bone repair?
Polymethyl methacrylate (PMMA) bone cement has been used in clinics for its excellent mechanical properties and simple operation procedure. However, there are still defects such as poor biocompatibility and overheating resulting from solidification.
