Large segmental bone defects are still one of the challenges for orthopaedic surgeons. Although 3D-printed porous titanium is a potential bone substitute material because of its porous structure simulating natural bone, the titanium surface has low bioactivity, integrates with bone tissue through the simple mechanical interlock. The study aims to investigate the capability and osteogenesis of 3D-printed porous titanium (3D PPT)-coated polydopamine (PDA) for repairing bone defects. Fifteen 6-month New Zealand white rabbits were implanted with PDA-3D PPT to repair 6 mm × 10 mm defects on the femoral condyle compared with the group of 3D PPT and comparing with the blank group. After 6 weeks and 12 weeks, micro-CT and histological examination were performed to observe bone growth. All the PDA-3D PPT group, the 3D PPT group and the blank group recovered in good condition. The images showed that the boundaries between the implant area and the surrounding area were obscure in the three groups. The results of micro-CT demonstrated that at 6 weeks and 12 weeks, the bone volume (BV) values of PDA-3D PPT implants group were significantly higher than those of the 3D PPT implants group and blank group (P < 0.05), the BV/tissue volume (TV) and the trabecular number (Tb.N) of PDA-3D PPT implants were significantly higher than those of the 3D PPT group and blank group (P < 0.05). The results of un-decalcified bone slicing showed that ore new bone appeared to form around the PDA-3D PPT than that of 3D PPT and blank group. The bone-implant contact (BIC) of PDA-3D PPT was better (P < 0.05) than that of 3D PPT group. PDA-3D PPT could improve the bioactivity and promote the growth and healing of bone tissue and can be a promising repairing material.

中文翻译：

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3D打印的钛植入物涂层聚多巴胺修复兔股骨con缺损

大块的骨缺损仍然是整形外科医生的挑战之一。尽管3D打印的多孔钛由于其模拟天然骨骼的多孔结构而成为潜在的骨替代材料，但钛表面的生物活性较低，并通过简单的机械互锁与骨组织整合。这项研究旨在研究3D打印多孔钛（3D PPT）涂层的聚多巴胺（PDA）修复骨缺损的能力和成骨作用。与3D PPT组相比，与空白组相比，将15只6个月大的新西兰白兔植入PDA-3D PPT以修复股骨dy上的6 mm×10 mm缺损。在6周和12周后，进行微CT和组织学检查以观察骨生长。所有PDA-3D PPT组，3D PPT组和空白组恢复良好。图像显示，在三组中，植入物区域与周围区域之间的边界模糊。micro-CT结果显示，在第6周和第12周时，PDA-3D PPT植入物组的骨体积（BV）值显着高于3D PPT植入物组和空白组的骨体积（P <0.05）， PDA-3D PPT植入物的BV /组织体积（TV）和小梁数目（Tb.N）显着高于3D PPT组和空白组（P <0.05）。未脱钙的骨切片结果表明，与3D PPT和空白组相比，PDA-3D PPT周围出现了新的矿石形成。PDA-3D PPT的骨-植入物接触（BIC）优于3D PPT组（P <0.05）。