运动对骨软骨骨折转归影响及其MRI表现

目的：观察运动对骨软骨骨折转归影响及其MRI表现，探讨骨软骨骨折与剥脱性骨软骨炎的关系。方法：将40只新西兰大白兔人工造成骨软骨骨折的动物模型，随机分成两组，外固定组和无固定组。分别于术后1、2周行MRI检查．之后处死动物行组织学检查。结果：MRI表现，术后1周，两组骨折线均清晰。术后2周，外固定组骨折线模糊：无固定组骨折线仍清晰，其MRI表现类似剥脱性骨软骨炎。组织学观察，术后1周，骨折区外固定组较无固定组成骨细胞数多、成软骨细胞数少（P〈0．051，外固定组成纤维细胞数与无固定组间无显著差异（P〉0.05）。术后2周，骨折区外固定组较无固定组成纤维细胞数、成软骨细胞数少、成骨细胞数多（P〈0．05）；无固定组病理表现类似剥脱性骨软骨炎。结论：兔膝关节骨软骨骨折，术后2周无固定组的转归，其MRI表现及病理变化类似剥脱性骨软骨炎。

The affection of movement in osteochondral fracture development with the MRI features

Objective:To observe the affection of movement in osteochondral fracture development with the MRI featurs.To study the relationship between the osteochondral fracture and the osteochondritis dissecans.Methods:40 young healthy Newzealand rabbits were chosen randomly. We made osteochondral fracture model. After models established, all the models were divided into two groups randomly, external fixation group and unfixed group. 10 experimental rabbits were chosen in both groups respectively and randomly and undertaken MRI examination after one week and two weeks. Results:MRI displaying,after one week, the fracture lines in both groups were clear; After two weeks, the fracture lines of external fixation group were clear, but the fracture lines of unfixed group were still dim, similarly to the MRI displaying of osteochondritis dissecans. Histopathological observation,one week later, more osteoblast cells were shown in bone fracture zone in external fixation group than that in the unfixed group; but less chondroblast cell were shown than unfixed group(P<0.05). There was no statistical significance in the collagenoblast cells between the unfixed group and the external fixation group(P>0.05). Two weeks later, the collagenoblast cells and the chondroblast cells in the external fixation group were less than that in unfixed group; the osteoblast cells in the external fixation group were more than that in unfixed group (P<0.05). For the unfixed group, The pathological changes were similar to the changes of osteochondritis dissecans. Conclusion:For the osteochondral fracture of rabbit knee joint, the unfixed group, MRI features and pathological changes of osteochondral fracture were similar to osteochondritis dissecans.