Anatomic Reconstruction Of Posterior Acetabular Defects With Iliac Crest Autograft Under Persistent Osteogenic Stress: An Experiment Study

Objective To evaluate the effect of anatomic reconstruction on the reconstructive posterior wall and its mechanism. Methods Adult male canines had surgeries to create animal models of posterior acetabular defects, which were created with the 60°arc fragment removed. Different measures were taken to reconstruct the defect region with iliac crest autograft. The animals were sacrificed and the pelves attached femurs were harvested to analyzed the biomechanics, strength, histology, osteoblast biological behaviour and osteogenetic protein-1 mRNA expression of the reconstructive posterior acetabular defect. Results Under the load of 250N,there were significant difference (P<0.05) in the mean pressure. There were significant difference on bone strength and bone porosity at 8th and 12th (P<0.05) after operation. Osteoblast proliferation showed significant differences at 48, 72 and 96 hours (P<0.05). There were significantly difference (P<0.05) in OP-1 mRNA expression at 2nd, 3rd and 4th week. There was significant difference (P<0.01) in repaired cartilages according to Pineda scoring at 12th week. Conclusions The anatomic reconstruction of posterior wall could restore distribution of the pressure within the acetabulum toward the intact state. The conformability of anatomic iliac crest autograft benefits persistent osteogenic stress and promote repair efficency. SRGF is capable of up-regulating the proliferation of canine osteoblast. OP-1 mRNA expression have the ability of inducing new bone formation. The small cylindrical cartilage autograft is an alternative method for the repair of articular cartilage defects.