接骨板固定及取出后局部骨量、骨结构和骨强度变化的相关研究

目的：了解坚硬接骨板固定及取出后局部骨量，骨结构和骨强度的变化及其相关性。方法：选用成年新西兰兔７２只，８只正常对照。６４只在左胫骨作不锈钢固定，其中４０只于术后２月取钢板，然后在取钢板当时及取钢板后１，２，３和４个胃８只动物处死。另有２４只动物不取钢板，至内固定后３，４和６月份分期处死。取材作光镜，定量组织分别有８只动物处死。

THE INTER-RELATION AMONG LOCAL CHANGES OF BONE MASS,COLLAGEN FIBER ORIENTATION AND STRENGTH OF PLATED BONE AFTER RIGID PLATE FIXATION AND REMOVAL

Aim: To revel the relationship between porosity, collagen fiber orientation and strengh of theplated bone after rigid plate fixation and removal. Methods: Seventy-two new zealand white rabbitswere used in this experiment. Eight anmals served as control and the other sixty-four were platedon their intact left tibiae with stailess steel (316L) 4-hole plates to induce early osteoporosis. Theplates were removed 2 months after internal fixation in 40 plated animals, 8 of which were sacrificedimmediately following plate removal and the other 32 were killed in successive groups of & each at1,2,3 and 4 months after plate removal. The remaining 24 plated animals were killed at 3,4 and 6months after plate fixation. After sacrifice, the samples of plated bone were prepared for lightmicroscopy, quantitative histological analysis, polarized light microscopy and biomechanical test.Results: The internal fixation with a rigid plate could induce the regional osteoporosis whichmanifested both bone loss and disorganized bone structure (loss of the orientation of the collagenfibers) leading to decreased strength of the plated bone. Although the regional osteoporois couldrecover gradually after plate removal, the bone structure remained disorderly when the bone masshad returned to normal. Delayed restoration of bone structure was related to delayed restoration ofbone strength. Conclusion f Besides the bone loss, the disorganized bone structure is the main causeof decrease of bone strength after rigid plate fixation and removal.