PLDLA mesh and 60/40 biphasic calcium phosphate in iliac crest regeneration in the goat.

Although morbidity of the iliac crest after grafting has been reported to occur frequently, it is the most widely used donor site. A proper regeneration of the defect could decrease morbidity. The purpose of this study was to evaluate the efficacy of two types of reconstruction of standardized critical size defects of the iliac crest after 3, 6, and 12 months. Standardized critical defects in iliac crests were bilaterally reconstructed in 28 goats randomly with (1) no reconstruction (group A); (2) a bioresorbable polylactide mesh (group B); or (3) 60/40 biphasic calcium phosphate (BCP) granules placed within a bioresorbable mesh (group C). At follow up, the iliac crests were harvested for histologic, histomorphometric, and radiologic analyses. The defects treated with "mesh-BCP" (group C) showed a significantly (p = 0.03) larger area with diffuse bone formation, while only a small area of high density trabecular bone ingrowth was observed in the "no reconstruction" (group A) and "mesh group" (group B). However, no difference in the total volume of bone was observed; in group C, the bone was more diffusely spread over the defect. Substitution of the BCP granules by trabecular bone did not start before 6 months. At the 12 months time point, extensive resorption of BCP was found because of phagocytic activity of numerous multinucleated giant cells. We confirm the positive influence of BCP on bone formation but due to a slow rate of resorption of BCP, regeneration takes a relatively long period of time.