ABSTRACT
In this study, 3D porous bioactive composite scaffolds were produced and evaluated for their physico-chemical and biological properties. Polymer poly-L-lactide-co-glycolide (PLGA) matrix scaffolds were modified with sol-gel-derived bioactive glasses (SBGs) of CaO-SiO2-P2O5 systems. We hypothesized that SBG incorporation into PLGA matrix would improve the chemical and biological activity of composite materials as well as their mechanical properties. We applied two bioactive glasses, designated as S2 or A2, differing in the content of SiO2 and CaO (i.e. 80 mol% SiO2, 16 mol% CaO for S2 and 40 mol% SiO2, 52 mol% CaO for A2). The composites were characterized for their porosity, bioactivity, microstructure and mechanical properties. The osteoinductive properties of these composites were evaluated in human bone marrow stromal cell (hBMSC) cultures grown in either standard growth medium or treated with recombinant human bone morphogenetic protein-2 (rhBMP-2) or dexamethasone (Dex). After incubation in simulated body fluid, calcium phosphate precipitates formed inside the pores of both A2-PLGA and S2-PLGA scaffolds. The compressive strength of the latter was increased slightly compared to PLGA. Both composites promoted superior hBMSC attachment to the material surface and stimulated the expression of several osteogenic markers in hBMSC compared to cells grown on unmodified PLGA. There were also marked differences in the response of hBMSC to composite scaffolds, depending on chemical compositions of the scaffolds and culture treatments. Compared to silica-rich S2-PLGA, hBMSC grown on calcium-rich A2-PLGA were overall less responsive to rhBMP-2 or Dex and the osteoinductive properties of these A2-PLGA scaffolds seemed partially dependent on their ability to induce BMP signaling in untreated hBMSC. Thus, beyond the ability of currently studied composites to enhance hBMSC osteogenesis, it may become possible to modulate the osteogenic response of hBMSC, depending on the chemistry of SBGs incorporated into polymer matrix.
Subject(s)
Bone Substitutes/chemistry , Bone and Bones/chemistry , Ceramics/chemistry , Lactic Acid/chemistry , Polyglycolic Acid/chemistry , Tissue Scaffolds/chemistry , Adult , Aged , Alkaline Phosphatase/chemistry , Bone Marrow Cells/cytology , Cell Survival , Cells, Cultured , Collagen/chemistry , Female , Humans , Male , Materials Testing , Microscopy, Confocal , Microscopy, Electron, Scanning , Middle Aged , Osteogenesis , Polylactic Acid-Polyglycolic Acid Copolymer , Porosity , Silicon Dioxide/chemistry , Stress, Mechanical , Stromal Cells/cytology , Tissue EngineeringABSTRACT
The purpose of this study was to evaluate the outcomes of total knee replacement using endoprostheses. The material consisted of 78 knee endoprostheses in 68 patients operated in our Clinic over a 3-and-a-half-year period beginning in March 1995. Outcome assessment was based on clinical and radiological examinations before and after surgery, with due regard for the patient's subjective evaluation. The average follow-up period was 13 months. The majority of the patients were found to have improved walk efficiency, eliminated or reduced pain, improved mobility, corrected limb axis, and excellent subjective evaluation.