Biomedical subjects

E Goyenvalle

Publications and source records attributed to E Goyenvalle.

3 recordsLinked to original sources

PubMed2005

Small-animal models for testing macroporous ceramic bone substitutes.

The aim of this study was to compare the bone colonization of a macroporous biphasic calcium phosphate (MBCP) ceramic in different sites (femur, tibia, and calvaria) in two animal species (rats and rabbits). A critical size defect model was used in all cases with implantation for 21 days. Bone colonization in the empty and MBCP-filled defects was measured with the use of backscattered electron microscopy (BSEM). In the empty cavities, bone healing remained on the edges, and did not bridge the critical size defects. Bone growth was observed in all the implantation sites in rats (approximately 13.6-36.6% of the total defect area, with ceramic ranging from 46.1 to 51.9%). The bone colonization appeared statistically higher in the femur of rabbits (48.5%) than in the tibia (12.6%) and calvaria (22.9%) sites. This slightly higher degree of bone healing was related to differences in the bone architecture of the implantation sites. Concerning the comparison between animal species, bone colonization appeared greater in rabbits than in rats for the femoral site (48.5% vs. 29.6%). For the other two sites (the tibia and calvaria), there was no statistically significant difference. The increased bone ingrowth observed in rabbit femurs might be due to the large bone surface area in contact with the MBCP ceramics. The femoral epiphysis of rabbits is therefore a favorable model for testing the bone-bonding capacity of materials, but a comparison with other implantation sites is subject to bias. This study shows that well-conducted and fully validated models with the use of small animals are essential in the development of new bone substitutes.

Animals↗

PubMed2003

Bilayered calcium phosphate coating to promote osseointegration of a femoral stem prosthesis.

A bilayered bioactive-gradient coating, consisting of a superficial layer of biphasic calcium phosphate (BCP) and a deep layer of hydroxyapatite (HA), promotes faster osseointegration and higher shear strength in non-loading conditions than do monolayer BCP or HA coatings. This study evaluated the biofunctionality of this coating in weight-bearing conditions at 6 and 12 months. The coating was plasma-sprayed on the metaphyseal portion of a sandblasted Ti6Al4V canine femoral prosthesis implanted using the surgical press-fit technique. An identical uncoated stem served as the control. Metaphyseal bone-to-implant apposition was increased for coated ( approximately 90% and 80% respectively at 6 and 12 months) as compared to uncoated implant ( approximately 7% at 6 and 12 months). Limited bone apposition was observed at the diaphyseal level. After 12 months, the uncoated implant interface consisted of well-organized, active fibrous tissue, whereas only inactive fibrous tissue interposition was observed at diaphyseal levels of the coated implant. At 6 months, the mineralization apposition rate (MAR) was similar, regardless of implant or bone structures. At 12 months, a significant decrease of MAR was observed around the uncoated implant. Transmission electron microscopy studies of the interface showed precipitation of biological apatite crystals in close association with mineralized collagenous bone matrix. Our results suggest a direct relationship between bioactivity and enhanced bone formation. The sandwich coating used is effective in promoting massive metaphyseal osseointegration, which ensures mechanical stability for early weight-bearing and should prevent long-term complications.

Journal Article↗

PubMed2001

Macroporous biphasic calcium phosphate ceramics versus injectable bone substitute: a comparative study 3 and 8 weeks after implantation in rabbit bone.

Macroporous biphasic calcium phosphate ceramics (MBCP) and a calcium phosphate injectable bone substitute (IBS), obtained by the association of biphasic calcium phosphate (BCP) ceramic granules and an aqueous solution of a cellulosic polymer, were compared in the same animal model. The two tested biomaterials were implanted in distal femoral osseous defects in rabbits. Qualitative and quantitative histological evaluation was performed three and eight weeks after implantation to investigate bone colonization and ceramic biodegradation associated with the two bone substitutes. Both biomaterials expressed osteoconduction properties and supported the apposition of a well-mineralized lamellar newly-formed bone. Bone colonization occurred much earlier and faster for IBS than for MBCP implants, although the respective rates of newly-formed bone after eight weeks of implantation did not differ significantly. For both biomaterials, ceramic resorption occurred regularly throughout the implantation period, though to a greater extent with IBS than with MBCP implants. The associated polymer in IBS produced intergranular spaces allowing body fluids to reach each BCP ceramic granule immediately after implantation, which may have favored osteoblastic activity, new bone formation and ceramic resorption. This completely interconnected open macroporosity could account for the earlier and more satisfactory bone substitution achieved with IBS.

Journal Article↗