动态应力钢板与AO钢板对羊股骨干骨折愈合的影响

背景:目前钢板内固定治疗骨折愈合出现应力遮挡影响骨折愈合。目的:观察动态应力钢板(CO钢板)与普通应力钢板(AO钢板)治疗羊股骨干骨折愈合的效果。方法:24只山羊制备股骨干骨折模型,造模后随机分为2组,AO钢板组和CO钢板组分别用AO、CO钢板内固定,分别在1,2,3周取出股骨,常规行X射线与磁共振扫描。结果与结论:X射线显示1周时,两组钢板骨折断端均未见明显变化,骨折线清晰可见;2周AO钢板组骨折断端无明显变化,骨折线明显,CO钢板组骨折断端骨密度增高,骨折线开始变模糊;3周AO钢板组骨折断端骨密度增加,CO钢板组骨折断端骨密度继续增高,出现云絮状外骨痂。MRI显示1周时,两组钢板骨折断端T1WI呈高信号,T2WI压脂序列上呈低信号,但AO钢板组骨折断端PDIR-TSE呈低信号,CO钢板组呈高信号。2周时两组骨折断端T1WI呈等或高信号,在T2WI压脂序列上呈等或低信号,AO钢板组PDIR-TSE呈低信号,CO钢板组呈高信号。3周AO钢板组可见骨折线明显,骨折断端在T1WI呈等或低信号,在T2WI压脂序列上呈等低信号,PDIR-TSE呈低信号;CO钢板组骨折断端可见骨折线模糊,骨折断段在T1WI上呈等或高信号,在T2WI压脂序列上呈等或低信号,PDIR-TSE呈等或高信号。提示CO钢板组骨折断端的血液循环、骨痂含量均优于AO钢板组骨折断端。

Effect of dynamic stress plate and AO plate on the healing of sheep femoral shaft fractures

BACKGROUND： Stress shielding can influence the healing of fracture in the treatment of fracture healing by plate fixation. OBJECTIVE： To observe the effect of dynamic stress plate （CO plate） and the normal stress plate （AO plate） on sheep femoral shaft fracture healing. METHODS： Twenty-four healthy adult sheep were prepared for establishing the femoral shaft fracture model. After modeling, the models were divided into two groups： AO plate group and CO plate group. The fractures in the two groups were fixed with AO and CO plate respectively. The femurs with the internal fixation were picked out at 1, 2 and 3 weeks; conventional X-ray and MRI scanning were performed. RESULTS AND CONCLUSION： X-ray film showed that there was no significant change at the fracture broken ends in two groups, and the fracture line was clear at 1 week after fixation; at 2 weeks after fixation, there was no significant change at the fracture broken end in AO plate group and the fracture line was clear, while in the CO plate group, the bone mineral density at the fracture broken end was increased and the fracture line began to blur; at 3 weeks after fixation, the bone mineral density at the fracture broken end in the AO plate group was increased, the bone mineral density in the CO plate group was increased continuously with the cloud-shaped external callus. MRI scanning showed that at 1 week after fixation, the T1 weighted imaging of the fracture broken end in two groups presented a high signal and the T2 weighted imaging on the fat saturation sequence presented a low signal, but the PDIR-TSE of the fracture broken end in the AO plate group showed a low signal and showed a high signal in CO plate group; at 2 weeks after fixation, T1 weighted imaging of the fracture broken end in two groups presented an equal or higher signal and the T2 weighted imaging on the fat saturation sequence presented a equal or lower signal, while the PDIR-TSE of the fracture broken end in the AO plate group showed a low signal and showed a high signal in CO plate group; at 3 weeks after fixation in the AO plate group, clearly fracture line could be seen, the T1 weighted imaging of the fracture broken end presented an equal or lower signal and the T2 weighted imaging on the fat saturation sequence presented an equal or lower signal, while the PDIR-TSE of the fracture broken end showed a low signal; at 3 weeks after fixation in the CO plate group, the fracture line at the fracture broken end was blur, the T1 weighted imaging of the fracture broken end presented an equal or higher signal and the T2 weighted imaging on the fat saturation sequence presented an equal or lower signal, while the PDIR-TSE of the fracture broken end showed an equal or higher signal. The blood circulation and the bone callus content at the fracture broken end in the CO plate group were higher than those in the AO plate group.