Zhao Yi-Nan, Fan Jun-Jun, Li Zhi-Quan, Liu Yan-Wu, Wu Yao-Ping, Liu Jian
Department of Orthopedics Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
Artif Organs. 2017 Feb;41(2):199-204. doi: 10.1111/aor.12742. Epub 2016 Jul 12.
Calcium phosphate cement (CPC) porous scaffold is widely used as a suitable bone substitute to repair bone defect, but the optimal pore size is unclear yet. The current study aimed to evaluate the effect of different pore sizes on the processing of bone formation in repairing segmental bone defect of rabbits using CPC porous scaffolds. Three kinds of CPC porous scaffolds with 5 mm diameters and 12 mm length were prepared with the same porosity but different pore sizes (Group A: 200-300 µm, Group B: 300-450 µm, Group C: 450-600 µm, respectively). Twelve millimeter segmental bone defects were created in the middle of the radius bone and filled with different kinds of CPC cylindrical scaffolds. After 4, 12, and 24 weeks, alkaline phosphatase (ALP), histological assessment, and mechanical properties evaluation were performed in all three groups. After 4 weeks, ALP activity increased in all groups but was highest in Group A with smallest pore size. The new bone formation within the scaffolds was not obvious in all groups. After 12 weeks, the new bone formation within the scaffolds was obvious in each group and highest in Group A. At 24 weeks, no significant difference in new bone formation was observed among different groups. Besides the osteoconductive effect, Group A with smallest pore size also had the best mechanical properties in vivo at 12 weeks. We demonstrate that pore size has a significant effect on the osteoconductivity and mechanical properties of calcium phosphate cement porous scaffold in vivo. Small pore size favors the bone formation in the early stage and may be more suitable for repairing segmental bone defect in vivo.
磷酸钙骨水泥（CPC）多孔支架作为一种合适的骨替代物被广泛用于修复骨缺损，但最佳孔径尚不清楚。本研究旨在评估不同孔径对使用CPC多孔支架修复兔节段性骨缺损时骨形成过程的影响。制备了三种直径为5mm、长度为12mm的CPC多孔支架，孔隙率相同但孔径不同（A组：200 - 300μm，B组：300 - 450μm，C组：450 - 600μm）。在桡骨中部制造12mm的节段性骨缺损，并用不同种类的CPC圆柱形支架填充。4周、12周和24周后，对所有三组进行碱性磷酸酶（ALP）、组织学评估和力学性能评价。4周后，所有组的ALP活性均升高，但孔径最小的A组最高。所有组支架内的新骨形成均不明显。12周后，每组支架内的新骨形成明显，A组最高。24周时，不同组之间新骨形成无显著差异。除了骨传导作用外，孔径最小的A组在12周时体内力学性能也最佳。我们证明孔径对磷酸钙骨水泥多孔支架在体内的骨传导性和力学性能有显著影响。小孔径有利于早期骨形成，可能更适合体内修复节段性骨缺损。
