关键词: 兔, 股骨髁, 骨缺损, 多孔钛, 3D打印

Abstract: Objective To investigate the ability of the 3D printed porous titanium material for bone defect repairing and bone formation. Methods The critical bone defect models (6 mm in depth and 10 mm in diameter) were made of 20 six-month-old New Zealand white rabbits’ femoral condyle. One of the porous titanium material was swiftly implanted into the bone defect area (experimental group, n=20), with the opposite side as control group (also the blank group, n=20), washed with saline and sutured without any implants. The samples were harvested and observed by X-ray and CT examinations at 3 days and 4, 8, 12 weeks after the operation to assess bone growth in the bone defect area. At 12 weeks after the operation, all rabbits were euthanized and evaluate the bone defect repair through X-ray, CT, histology and Micro-CT. Results Both the experimental group and control group recovered with good condition. At 12 weeks after the operation, we can see that the bone defect area was filled with new bone in the experimental group after removing the soft tissue surrounding the bone defect area; In contrast, the bone defect in control group was seen hollow and covered with fibrous capsule. According to the radiological observation, the demarcation line between the defect area and the surrounding area was obscure in the experimental group; the bone defect area in control group saw an entire translucency with no obvious shadow reflecting the new-borne bone. The Micro-CT observations proved fresh bone tissue formed in the plantation area at 12 weeks after the operation, and the surrounding area could see bone trabecula grown, In comparison, there was no obvious bone formed in the defect area of control group, which was filled by fiber tissue and relatively less bone trabecula and new-borne bone tissue. The results of un-decalcificated bones slicing showed the implanted material appeared combined with osteoblast, and the mature harversian system was seen distributed within the new-borne bone; for control group, a small amount of unordered bone formed in the defect area, filled with a lot of fiber texture. The area ratio of new-borne bone and the defect area was calculated via the IPP5.1 software, producing differences that have statistical significance. Conclusion A series of experiments prove that the porous titanium material has high biosecurity and ability to promote bone growth and healing. The new-borne bone tissue can grow and fill the lacuna, thereby effectively repairing bone defect. In short, the 3D printed porous titanium is a kind of promising repairing material in the tissue engineering field.

Key words: Rabbits, Femoral condyle, Bone defect, Porous titanium, 3D printing