Biomaterial Database

Porosity reduction in bone cement at the cement-stem interface. 1996

N E Bishop, and S Ferguson, and S Tepic

AO/ASIF Research Institute, Davos, Switzerland.

The fatigue failure of bone cement, leading to loosening of the stem, is likely to be one mode of failure of cemented total hip replacements. There is strong evidence that cracks in the cement are initiated at voids which act as stress risers, particularly at the cement-stem interface. The preferential formation of voids at this site results from shrinkage during polymerisation and the initiation of this process at the warmer cement-bone interface, which causes bone cement to shrink away from the stem. A reversal of the direction of polymerisation would shrink the cement on to the stem and reduce or eliminate the formation of voids at this interface. We have investigated this by implanting hip prostheses, at room temperature or preheated to 44 degrees C, into human cadaver femora kept at 37 degrees C. Two types of bone cement were either hand-mixed or vacuum-mixed before implantation. We found that the area of porosity at the cement-stem interface was dramatically reduced by preheating the stem and that the preheating temperature of 44 degrees C determined by computer analysis of transient heat transfer was the minimum required to induce initial polymerisation at the cement-stem interface. Temperature measurements taken during these experiments in vitro showed that preheating of the stem caused a negligible increase in the temperature of the bone. Reduction of porosity at the cement-stem interface could significantly increase the life of hip arthroplasties.

UI	MeSH Term	Description	Entries
D008422	Materials Testing	The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.	Biocompatibility Testing,Biocompatible Materials Testing,Hemocompatibility Testing,Testing, Biocompatible Materials,Testing, Hemocompatible Materials,Hemocompatibility Testings,Hemocompatible Materials Testing,Materials Testing, Biocompatible,Materials Testing, Hemocompatible,Testing, Biocompatibility,Testing, Hemocompatibility,Testing, Materials,Testings, Biocompatibility
D011108	Polymers	Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).	Polymer
D011475	Prosthesis Failure	Malfunction of implantation shunts, valves, etc., and prosthesis loosening, migration, and breaking.	Prosthesis Loosening,Prosthesis Durability,Prosthesis Migration,Prosthesis Survival,Durabilities, Prosthesis,Durability, Prosthesis,Failure, Prosthesis,Failures, Prosthesis,Loosening, Prosthesis,Loosenings, Prosthesis,Migration, Prosthesis,Migrations, Prosthesis,Prosthesis Durabilities,Prosthesis Failures,Prosthesis Loosenings,Prosthesis Migrations,Prosthesis Survivals,Survival, Prosthesis,Survivals, Prosthesis
D001843	Bone Cements	Adhesives used to fix prosthetic devices to bones and to cement bone to bone in difficult fractures. Synthetic resins are commonly used as cements. A mixture of monocalcium phosphate, monohydrate, alpha-tricalcium phosphate, and calcium carbonate with a sodium phosphate solution is also a useful bone paste.	Bone Cement,Bone Glues,Bone Pastes,Bone Glue,Bone Paste,Cement, Bone,Cements, Bone,Glue, Bone,Glues, Bone,Paste, Bone,Pastes, Bone
D002102	Cadaver	A dead body, usually a human body.	Corpse,Cadavers,Corpses
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D006622	Hip Prosthesis	Replacement for a hip joint.	Femoral Head Prosthesis,Femoral Head Prostheses,Hip Prostheses,Prostheses, Femoral Head,Prostheses, Hip,Prosthesis, Femoral Head,Prosthesis, Hip
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013314	Stress, Mechanical	A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.	Mechanical Stress,Mechanical Stresses,Stresses, Mechanical
D013816	Thermodynamics	A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)	Thermodynamic