The effect of particle size on the osteointegration of injectable silicate-substituted calcium phosphate bone substitute materials.
Calcium phosphate (CaP) particles as a carrier in an injectable bone filler allows less invasive treatment of bony defects. The effect of changing granule size within a poloxamer filler on the osteointegration of silicate-substituted calcium phosphate (SiCaP) bone substitute materials was investigated in an ovine critical-sized femoral condyle defect model. Treatment group (TG) 1 consisted of SiCaP granules sized 1000-2000 μm in diameter (100 vol %). TG2 investigated a granule size of 250-500 μm (75 vol %), TG3 a granule size of 90-125 μm (75 vol %) and TG4 a granule size of 90-125 μm (50 vol %). Following a 4 and 8 week in vivo period, bone area, bone-implant contact, and remaining implant area were quantified within each defect. At 4 weeks, significantly increased bone formation was measured in TG2 (13.32% ± 1.38%) when compared with all other groups (p = 0.021 in all cases). Bone in contact with the bone substitute surface was also significantly higher in TG2. At 8 weeks most new bone was associated within defects containing the smallest granule size investigated (at the lower volume) (TG4) (42.78 ± 3.36%) however this group was also associated with higher amounts of fragmented SiCaP. These smaller particles were phagocytosed by macrophages and did not appear to have a negative influence on healing. In conclusion, SiCaP granules of 250-500 μm in size may be a more suitable scaffold when used as an injectable bone filler and may be a convenient method for treating bony defects.
Division of Surgery and Interventional Science, John Scales Centre for Biomedical Engineering, Institute of Orthopaedics and Musculoskeletal Science, University College London, The Royal National Orthopaedic Hospital, Brockley Hill, Stanmore Middlesex, HA7 4LP, UK. m.coathup@ucl.ac.uk
Melanie J
MJ
Coathup
Qian
Q
Cai
Charlie
C
Campion
Thomas
T
Buckland
Gordon W
GW
Blunn
D000818:Animals; D001861:Bone Regeneration; D018786:Bone Substitutes / Q000008:administration & dosage / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D005260:Female; D005269:Femur / Q000473:pathology / Q000601:surgery; D007267:Injections; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D016348:Osseointegration; D010316:Particle Size; D020442:Poloxamer / Q000737:chemistry; D034561:Sheep, Domestic; D017640:Silicates / Q000737:chemistry*; D054457:Tissue Scaffolds / Q000737:chemistry
D018786:Bone Substitutes; D002130:Calcium Phosphates; D017640:Silicates; D020442:Poloxamer; C020243:calcium phosphate
animal model; bone regeneration; particle size; silicate-substituted calcium phosphate