Cytocompatibility study of organic matrix extracted from Caribbean coral porites astroides.

Since 1980, natural coral exoskeleton has been widely used as bone graft substitute. Despite numerous in vitro and in vivo studies. there is still a lack of knowledge concerning the organic matrix associated with coral exoskeleton (COM). In fact, some surgical interventions have failed and this has sometimes been attributed to the exoskeleton organic matrix. For others, only amino acids are present in the matrix after coral preparation for clinical use. The objective of this study was to extract the exoskeleton organic matrix to carry out biochemical analysis and study its specific cytocompatibility. Demineralized bone powder (DBP) was used as control. A decalcification process was used to extract COM and DBP. Protein, carbohydrate and glycosaminoglycan analysis was carried out in DBP and COM using classical staining methods. Human bone marrow cells were cultured in the presence of 20, 40, 80, 160 microg of COM or DBP for 24, 48 and 72 h. The methods used to analyze COM and DBP effects were scanning electron microscopy immunocytochemistry, manual cell count, and cyto-compatibility assay (Neutral red and MTT tests). Results showed that in spite of treating coral before clinical use, a COM was present in which GAG, protein and carbohydrate were found. The in vitro cytocompatibility of COM was confirmed for 20 and 40 microg values but was less pronounced for 80 and 160 microg levels.

Clinical, radiological and histological evaluation of biphasic calcium phosphate bioceramic wedges filling medial high tibial valgisation osteotomies.

We report clinical, radiological and histological findings following high tibial valgisation osteotomy (HTVO) using micro-macroporous biphasic calcium phosphate wedges fixed with a plate and locking screws. From 1999 to 2002, 43 knees were operated on and studied prospectively. All underwent clinical and radiological follow-up at days 1, 90, and 365 to evaluate consolidation and bone substitute interfaces. Additionally, biopsies were taken for histology at least 1 year after implantation from 10 patients who requested plate removal. Radiologically, consolidation was observed in 98% of cases. At 1 year, correction was unchanged in 95% of cases. Histological analysis revealed considerable MBCP resorption and bone ingrowth, both into the pores and replacing the bioceramic material. Polarised light microscopy confirmed normal bony architecture with trabecular and/or dense lamellar bone growth at the expense of the wedge implants. X-ray and micro-CT scan revealed a well organised and mineralised structure in the newly-formed bone. This study shows that using MBCP wedges in combination with orientable locking screws and a plate is a simple, safe and fast surgical technique for HTVO. The is the first study to examine the results by histological analysis, which confirmed good outcomes.