The effects of axial distraction forces on the distal epiphyseal plate of the right femur were studied in 32 New Zealand young white rabbits.A controlled distractional force of ON,5N and 10N every 3 days wasapplied through an external fixator composed of 2 strain gauges.The cntralateral side (left) was kept as a control.After 4 weeks,the length of all distracted femurs was significantly longer than that of the contralateral side and that of the group ON.Radiographs of hind limbs showed widening of the distal epiphyseal line and metaphysis of right femurs.Histological studies revealed no evidence of epiphyseal se paration.These results showed that limb lengthening by epiphyseal distration without a preliminary fracturing was attributable to applied force.The risk of premature closure of epiphyseal line,which is believed the worst complication in epiphyseal distraction,could be avoided and/or lessened.%采用新西兰幼兔32只,在右股骨下端骨骺安装外固定架和拉压传感器,对骨骺板近端分别施加张力0 N、5 N、10 N,并定期进行张力调节.4周后5 N、10 N张力组的右股骨长度值明显高于左侧股骨,也明显高于同侧对照组.X线片显示右股骨下端骨骺板与干骺端间隙增宽,组织学镜检尤一例出现骨骺分离骨折.研究结果表明适量的张力能刺激骨骺产生无骺分离状态下的骨延长,从而避免或减少骨骺牵张术中最严重的并发症--骨骺早期封闭.
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