Papers by Keyword: Bone Cement

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Authors: Julietta V. Rau, Marco Fosca, Vladimir S. Komlev
Abstract: In situ monitoring of structural changes, taking place upon calcium phosphate bone cements hardening process was carried out by means of the Energy Dispersive X-Ray Diffraction method. Two different cement systems were studied, one of them based on the octacalcium phosphate and another - on the dicalcium phosphate dehydrate. Both systems contained natural biopolymer chitosan and were soaked in Simulated Body Fluid. The obtained experimental results evidence that during the hardening of the cement containing octacalcium phosphate its partial transformation into hydroxyapatite takes place, whereas no significant changes were detected during the hardening process of cement containing the dicalcium phosphate dehydrate.
Authors: Hong Yu Zhang, Leigh Fleming, Liam Blunt
Abstract: The rationale behind failure of cemented total hip replacement is still far from being well understood in a mechanical and molecular perspective. In the present study, the integrity of the stem–cement interface was investigated through an in vitro experiment monitoring fluid flow along this interface. The results indicated that a good mechanical bonding formed at the stem–cement interface before debonding of this interface was induced by physiological loadings during the in vivo service of the hip prosthesis.
Authors: Hironobu Oonishi, Hiroyuki Oonishi Jr., Shigekazu Mizokawa, Hirotsugu Ohashi, Masaru Ueno, Mikio Iwamoto
Abstract: To improve the fixation of bone and bone cement in THA we used Interface Bioactive Bone Cement technique (IBBC) since 1982. For prostheses 28 mm-alumina head with polyethylene socket (Kyocera Co.) were used. In IBBC not-resorbable pure crystalline HA granules (0.3– 0.5 mm) were smeared on the bone surface in one to three layers just before packing bone cement. Group 1: IBBC was used in six joints in 1982. Group 2: In 25 patients, conventional bone cement technique (non-IBBC) in the one hip (in 1985 to 1986) and IBBC technique in the other hip (in 1986) were performed in the same patients. Group 3: In 65 patients (71 joints) IBBC were performed. Neither radiolucent line nor osteolysis appeared in all case in group 1. In group 2 in Non-IBBC the appearance rate of radiolucent line and osteolysis were rather high, however in IBBC they were extremely low. In Non-IBBC loosening were seen in 5 joints in the acetabulum and in 2 joints in the femur. However, in IBBC there was no loosening. In group 3 the radiolucent line and the osteolysis appeared extremely low. There was no loosening. In Non-IBBC the appearance rate of radiolucent line and the osteolysis was very high and the rate of loosening was 20%. However, in IBBC, radiolucent line and osteolysis will be prevented eternally.
Authors: Phanrawee Sriprapha, Chaiy Rungsiyakull, Kamonpan Pengpat, Tawee Tunkasiri, Sukum Eitssayeam
Abstract: In this research, mechanical properties of bone cement containing micro-and nanohydroxyapatite (HAp) particles were studied. The bone cement was prepared from mixing between polymethyl methacrylate (PMMA) and methyl methacrylate (MMA). Hydroxyapatite powder was prepared from bovine bone. The bone was heated in hot water at 200 oc for the elimination of tissue, after which the bone was dried and calcined at 800 oc for 3 hrs. The calcined bone than was crushed into powder and ball-milled for 24 hrs. The micro-HAp particle was then obtained. The micro particles were then further milled employing the Vibro-milling machine for 2 hrs. The micro-and nanoHAp sizes are about 0.5 μm and 140 nm, respectively. The both size powders were treated with γ-methacrylic-propyl-tri-methoxy silane. The acetic acid was added to control the pH of the solution, until it reached 2.9 before they were mixed into the bone cement with equally wt%. The mixture was casted using the 304 stainless steel mold in order to obtain a cylindrical shape. The low vacuum scanning electron microscope (LV-SEM) and x-ray diffractometer (XRD) were employed to characterize the samples. The porosity of PMMA could be reduced by HAp particle additives. From compressive strength test, it was found that the mixture of bone cement and nanoHAp particle has shown higher compressive strength than pure PMMA bone cement that affected by porosity reduction and force distribution by HAp particles.
Authors: Peter J. Catalano, G.M. Insley, Brian Hess
Abstract: The aim of this work was to assess the mixing, transfer and handling, properties, injectability, set time, wash-out characteristics, acceptance of hardware (i.e. stainless screws), and their delivery/transfer systems of self hardening synthetic bone cements made from calcium phosphate and calcium sulphate. Surgical procedures (i.e. cranioplasty) were performed on adult Labrador dogs using seven different bone cements from various manufacturers. Direct comparison of the defined intraoperative properties were evaluated and recorded. There is considerable variability with respect to application properties among commercially available injectable synthetic bone cements. Only one product was rated good to excellent in seven of the eight categories evaluated (6-excellent, 1-good, 1-fair) based on in-vivo tests. This study outlines the critical parameters required for successful implantation of cements that have to be understood when designing new injectable bone cements for the future.
Authors: Niklas Axén, Tobias Persson, Kajsa Björklund, Hakan Engqvist, Leif Hermansson
Authors: Xiao Hui Huang, Wen Guang Liu, Guo Qun Zhao, Xin Hai Zhao
Abstract: In this investigation, we propose a new concept to embed cohesive zone into the continuum structure of bone cement, an example of brittle material, in investigating the mechanical behavior and fracture mechanism and to predict the fracture which elastic fracture mechanics (EFM) is unable to. Four finite element (FE) models with embedded cohesive zones for the simulations of tensile, compression, double shear and 3-point bending tests have been implemented. Cohesive zones (CZ) are embedded at high risks of fracture with orientations determined by fracture mode. A bilinear cohesive traction-separation law (TSL) is applied. The fracture parameters in traction-separation curve are validated and justified in the simulations to agree well with the force-displacement curves in the four practical tests. Apart from the maximum load, the perpetual safe working load (SWL) in theory also can be predicted by tracing the history of the stiffness degradation of fractured cohesive zone by means of simulation. A distinct advantage of our numerical model is that it is able to extend to investigate the mechanical behavior and fracture mechanism of other brittle materials. The proposed method with embedded cohesive zones in FE models can be introduced to predict the fracture and to forecast the maximum load and safe working load (SWL) of the continuum structure in more complicated loading conditions.
Authors: Tai Joo Chung, Kyung Sik Oh
Abstract: The cause of the degradation was analyzed by applying the highly humid conditions during the storage of cement composed of β-tricalcium phosphate (β-TCP) and monocalcium phosphate monohydrate (MCPM). For the β-TCP and MCPM stored separately under the humid environment, the mild increase in the setting time was observed, and the product after the setting was entirely dicalcium phosphate dihydrate (CaHPO42H2O: DCPD). However, for the β-TCP and MCPM stored mixed under the same condition, the setting time significantly increased with the period of storage, and the product contained dicalcium phosphate (CaHPO4: DCP) as major phase, resulting in the loss of setting ability. The formation of DCP could be because of the weak driving force for setting, caused by a feeble supply of water from moisture. As the formation of DCPD requires stronger driving force to overcome the activation barrier, sufficient amount of water is essential. Humid environment during the storage decreased the driving force by the formation of DCP, and the driving force to produce DCPD was lost during the actual setting.
Authors: Hiroyuki Oonishi Jr., Tomonori Arita, Akira Tachibana, Toshizumi Tanabe, Shigekazu Mizokawa, Hironobu Oonishi
Abstract: Antibiotics release impregnated in HA granules, which were used in IBBC to prevent infection after total joint arthroplasty, was measured. For antibiotics, Flumarin, Vancomycin, Pansporin and Firstcin were used. Two models of antibiotics release were assumed; Model [I]: antibiotics release from surroundings of HA granules immediately after surgery and Model [II]: antibiotics release loaded on HA after antibiotics release from surroundings of HA granules as follows; (1) loading in normal pressure and (2) loading in reduced pressure. The amount of antibiotics loaded on HA is higher when loading is conducted under reduced pressure than that under normal pressure. Firstcin showed the highest loaded amount and the most desirable sustained release pattern. The antibiotics release from HA are varid depending on the antibiotics used.
Authors: Byung Hyun Lee, Min Chul Kim, Kyoung Nam Kim, Kwang Mahn Kim, Seong Ho Choi, Chong Kwan Kim, Racquel Z. LeGeros, Yong Keun Lee
Abstract: In preliminary ageing test, the cement using only calcium phosphate glass as power phase cracked with 1 day in simulated body fluid because of high dissolution rate of the cement. We added 30 wt% of either β-TCP or HA to 70 wt% calcium phosphate glass as powder phase to control the dissolution rate of the cement and performed in vitro ageing test in simulated body fluid by dynamic protocol as well as static protocol to confirm the possibility of controlling. Adding either β-TCP or HA to the cement increases the setting time and decreases the compressive strength. In dynamic assay, the pH of extract is maintained over 7. However, pH decreased to around 5 in static assay. Therefore, weight loss by static protocol continuously increased for 14 days, while weight loss by dynamic protocol almost saturated. In XRD patterns of ageing cements, CaO peaks appeared. CaO peak was maximized most lately in dynamic assay of the cement adding HA and within 7 days, the cement adding HA showed higher weight loss. It is indicated that CaO formed in surface of the cement hinder the dissolution of the cement. In addition, compressive strength increased when the CaO peak was maximized.
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