Abstract
Introduction and Aims: Calcium sulfates and phosphates have become popular as bone graft substitutes, however, their in-vivo performance has not been well characterised. The purpose of this study was to evaluate trabecular bone response to four synthetic graft materials (CaSO4 and CaSO4 – HA/TCP composites) as compared to autograft in a canine defect model.
Method: In this REB-approved RCT, bilateral humeral and femoral cylindrical defects were filled with one of four types of pellets with varying proportions of CaSO4 – HA/TCP, autograft bone, or left unfilled. After sacrifice at six or 12 weeks, defect sites were evaluated histologically for tissue and inflammatory response, area fractions of residual graft material, and bone ingrowth in the defects.
Results: The area of the defect occupied by residual graft material in the group with the highest percentage of HA/TCP was greater than in other composite groups (p< 0.0006). At 12 weeks, this group contained more total mineralised material (graft material + bone) (p< 0.005). The extent of new bone formation was not different among the composite groups at either time-point, but all showed more bone formation than the empty defect. Both 100% CaSO4 and the 3 CaSO4 – HA/TCP formulations showed good bone formation.
Conclusion: The group with the highest proportion of HA/TCP lasted longest, suggesting increased HA/TCP proportions reduce the rates of dissolution, without compromising bone formation in this model. Results suggest that a range of composites could be created to match the spectrum of resorption rates demanded by clinical applications.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
At least one of the authors is receiving or has received material benefits or support from a commercial source.
