EFFECT OF VOLUME VARIATIONS ON OSTEOGENIC CAPABILITIES OF AUTOGENOUS CANCELLOUS BONE-GRAFT IN DOGS

Objective-To evaluate the osteogenic effect of differing volumes of au togenous cancellous bone graft (ACBG) placed into partial cortical def ects of the ulna. Animals-15 healthy, mature Beagles. Procedure-Weekly radiographic views of defects were obtained over 8 weeks and were ana lyzed for bone density by use of radiographic optical densitometry. Hi stologic sections were obtained 8 weeks after surgery and were planime trically evaluated for area of total, lamellar, and woven bone. Result s-Defects receiving 0.3 and 0.75 g of ACBG had rapid initial bone prod uction, and dogs receiving 0.3 g of ACBG had faster bone ingrowth than did those receiving 0.1 g of ACBG or controls. Defects receiving 0.75 g of ACBG had a rate of bony ingrowth equal to 0.3 g of ACBG, There w as no difference in the histomorphometric area fractions of total, lam ellar, or woven bone between defects treated with 0.1 or 0.75 g of ACB G, and between grafted or control defects, 8 weeks after surgery. Conc lusions-Overfilling a cortical defect with ACBG does not enhance early osteogenesis within the defect, and underfilling will delay the onset of osteogenesis within the defect. Clinical Relevance-A volume of ACB G sufficient only to fill a cortical defect is required to obtain a cl inical osteogenic effect from the graft.