Papers by Keyword: Bone Substitute

Abstract: The purpose of this retrospective study is to evaluate the efficacy of a biphasic synthetic ceramic bone substitute (Eurocer) combined with plate fixation in treating collapse tibial plateau fractures. 32 patients were included in the study. The surgical protocol consisted of: elevation of the articular depression through a limited cortical window using a curved bone compactor and image intensification, filling the defect with Eurocer granules and fixation with plates. Clinical and radiologic follow-up after 36 to 48 months revealed uneventful primary bone healing, excellent osseous integration of Eurocer and a mean Neer score of 87, 5 points. We conclude that Eurocer400® combined with plate fixation in managing collapsed tibial plateau fracture is a promising alternative in this difficult lesion regarding a fast healing, a good quality osseointegration, preventing secondary collapse and improving medium term results.

Abstract: This study evaluates the effect of two novel particulate silicon-doped calcium phosphate graft materials as compared to the currently clinically used material β-TCP on osteogenesis and bone formation after implantation in critical-size defects the sheep scapula. These materials were developed in order to create biodegradable bone substitute materials that degrade rapidly, but still stimulate osteogenesis at the same time, thereby resulting in bone repair and regeneration with fully functional bone tissue. All bone substitute materials studied facilitated excellent bony regeneration of critical-size defects in the sheep scapula. Of the three grafting materials studied, the calcium alkali orthophosphate material with the crystalline phase Ca₂KNa (PO₄)₂, with a small amorphous portion containing magnesium potassium phosphate and a small addition of sodium magnesium silicate had the greatest stimulatory effect on bone formation and expression of osteogenic markers, while exhibiting the highest biodegradability.

Abstract: In this study, three - dimensional porous carbonate apatite (CO₃Ap) materials with the chemical compositions and structures similar to cancellous bone were produced via phosphorization of porous calcite precursor in hydrothermal condition. In order to make porous calcite precursor, negative replication of polyurethane foam that named as inverse ceramic foam method was conducted. When the polyurethane template occupied within the ceramic solid walls disappeared due to burning at high temperature, interconnected hollow pathways were produced. Polyurethane foam was used as a porogen - template firstly was coated layer by layer with synthetic resin to modify morphology and enlarge thickness of struts so as to expand porous area for satisficing cellular bioactivities. Calcium hydroxide (Ca(OH)₂) slurry was then infiltrated into resin coated-polyurethane foam. Heat treatment in atmosphere of oxygen and carbon dioxide gases was carried out to eliminate polyurethane template and induce carbonation process. Ca(OH)₂ was converted to calcite with the internal porous channel architecture simulating polyurethane foam struts network. That interconnected porous calcite was subsequently transformed to CO₃Ap with remaining the same macroporous structure through hydrothermal treatment in phosphate solution. The porous CO₃Ap materials were implanted in the tibia of Japanese male rabbits and removed after a period of 3 months. The bone formation response of the three - dimensional porous carbonate apatite in vivo has been preliminary studied using micro-computed tomography (µ-CT) scanner. The results showed that the porous implant materials have sufficient mechanical strength to provide structural support during bone remodeling and successfully bond with host bone.

Abstract: The present study reports the synthesis of carbonate apatite foam with fully interconnecting pores from βTCP foam by hydrothermal treatment in 1 mol·L^-1 disodium carbonate solution at 200°C. The βTCP foam were prepared; 1) using 3 mol% Mg as βTCP stabilizer, 2) using αTCP foam as a precursor by heat treatment at 900°C for 100 hours. The βTCP foam containing Mg could not transform to carbonate apatite foam completely. Meanwhile, the βTCP foam heat-treated at 900°C transformed to carbonate apatite after hydrothermal treatment for 10 days without morphological change. Compressive strength measurement indicated that the value of carbonate apatite foam derived from βTCP was significantly higher than that from αTCP.

Abstract: Physico-chemical characteristics impact directly or indirectly the bioactive properties of biomaterials, it is then essential to correlate it with their effect in vivo. A panel of biomaterials available on the market, based on Hydroxyapatite (HA) and Tricalcium phosphate (β-TCP) is studied in terms of surface area, hydrophilicity, porosity, zeta potential, crystalline phases and density. This study highlights the dispersity of commercial calcium phosphates (CaP) properties, and demonstrates how the quality criteria required for such bone substitute based on biomimicry concept, whose pores distribution is certainly the more relevant, are often incompletely or not respected according to literature.

Abstract: The aim of the present work is to study the influence of the precipitation temperature in the synthesis of nanohydroxyapatite (n-HAp) on the properties of the resulting n-HAp powder for the fabrication of highly porous scaffolds for bone tissue engineering. The n-HAp powder was obtained by a wet precipitation technique starting from calcium nitrate tetrahydrate (Ca (NO₃)₂*4H₂O) and phosphoric acid (H₃PO₄) at different temperatures: 10°C, 37°C and 50°C. Highly porous scaffolds were fabricated using the three different powders by the sponge replica method and sintering at 1300°C. Combined X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses on powders indicated that on increasing the precipitation temperature the formation of pure n-HAp is accelerated, without significant changes in particles morphology and size. Scaffolds characterized by high porosity (89%) and good compressive strength (0.53 MPa for n-HAp prepared at 37°C) were obtained. XRD analyses on sintered n-HAp confirmed the thermal stability of the material. Therefore, the as-synthesized n-HAp powder can be successfully used for the fabrication of highly porous scaffolds as bone substitutes.

Abstract: Benign lytic lesions represent a frequent pathology in our clinic. Regarding therapy, we approach these benign tumors through curettage and filling the defects with bone grafting or bone substitutes like hydroxyapatite crystals and tricalcium phosphate.We want to evaluate the efficiency of both bone grafts and bone substitutes regarding bone consolidation, osseointegration and time until absorption for tricalcium phosphate and hydroxyapatite crystals combination. We analyzed 14 patients treated in our clinic through curettage and defect filling during the last three years: 9 patients’ beneficiated from bone grafting and for the other 5 we used a hydroxyapatite and tricalcium phosphate combination from the same supplier. Diagnoses were bone cyst, non-ossifying fibroma and giant-cell tumor. Therapeutic method was linked with bone graft availability. Follow-up was 24 months through periodical x-ray controls in our clinic. Bone consolidation was satisfactory in all cases with no defect collapse. In conclusion, bone substitutes like combinations of hydroxyapatite crystals and tricalcium phosphate are a useful and safe method for surgical treatment of strictly benign lytic tumors.

Abstract: In order to induce bone regeneration several natural and synthetic materials have been proposed. However, single-phase scaffolds present some insurmountable disadvantages such as poor mechanical strength or brittleness and too low or too high degradation rate. In order to overcome these drawbacks, composite systems can be an interesting and promising option. In the present work a novel hybrid porous scaffold for bone tissue engineering is proposed. Chitosan/Forsterite (Ch/FS) composite scaffolds were prepared by freeze-drying method using a chitosan/forsterite ratio of 90/10. The FS nanopowder (Mg₂SiO₄) is synthesized using a simple solgel based method. The FS composition was checked by XRD analysis. The macrostructure of the Ch/FS scaffolds were analyzed by SEM, the FS distribution within the chitosan matrix observed by EDS, the mechanical strength measured by compression test in PBS and the biocompatibility of the composite on human osteosarcoma cell line (MG-63) verified by MTT assay after 48 hours. The porosity appears interconnected and with a pore size ranging from 1 to 100 μm. The FS is overall distributed within the chitosan matrix. The compression strength of composite scaffolds increased with respect to the pure chitosan scaffolds of more than two times (from 0.8 to 1.9 KPa) and the composites did not show any toxicity effect on human osteosarcoma cells.

Abstract: In the present study, a new antibacterial bone graft substitute has been developed for repairing bone defects and inhibiting related infections at the same time. Calcium sulphate hemihydrate (CSH) was introduced into nanohydroxyapatite/collagen (nHAC) to prepare a self-setting in situ bone repair materials. The nHAC/CSH was used as a carrier of vancomycin (VCM) for anti-infection and the treatment of osteomyelitis. The VCM/nHAC/CSH composite was a porous scaffold with porosity of 38.8% and the compressive mechanical strength was about 4.8 MPa. The final setting time was about 15~20 min. The inhibition ratio of VCM/nHAC/CSH was more than 99.8% and the distinct inhibition zone of 18 mm was formed in Staphylococcus aureus bacterium incubation dish with VCM/nHAC/CSH disc in the center of agar matrix for 16 hours of incubation. After incubating 17 days at 37 in vitro, the concentration of vancomycin in elution fluild was around 12 μg/mL. Therefore, the VCM/nHAC/CSH bone substitute presents ideal self-setting antibacterial, cytocompatibility, sustained release properties and has great potential applications for the treatment of bone defect-related infection in orthopedic surgeries.

Abstract: After a short introduction to bone substitute biomaterials and X-ray microtomography, this article describes a research work carried out for in-vitro characterization of bone substitute biomaterials as well as for in-vivo investigation of human bone grafted with biomaterials. Three different bone substitute biomaterials have been analyzed in-vitro by means of 3D microtomographic technique, while human bone samples grafted with bone substitute biomaterials are investigated by 3D microtomography and histological techniques. 3D images of bone substitutes and human bone samples with biomaterials have been obtained, together with morphometric parameters, by microtomography . 2D histological images have also been obtained by traditional technique only for human bone samples with biomaterials. Compared to traditional histological analysis, 3D microtomography shows better results for investigating bone tissue and bone substitute biomaterial, and in a short time. Nevertheless, histological analysis remains the best technique for the observation of soft tissue and blood vessels.