Effects of Stress－ Relaxation Plate on the Disorganization and Reparation of Regional Bone Structure
- VernacularTitle:应力松驰接骨板对骨结构的影响
- Author:
Xianlong, ZHANG
;
Kerong, DAI
;
Tingting, TANG
- Publication Type:Journal Article
- Keywords:
fractureinternal fixationstress－ relaxation platebone structure
- From:Journal of Shanghai Jiaotong University(Medical Science)
2000;20(6):488-490，499
- CountryChina
- Language:Chinese
-
Abstract:
ObjectiveTo study the influence of stress－ relaxation plate on disorganization andrepair of the cortex under the plate. MethodsA washer made of viscoelastic polyethylene was placedbetween the screw and the screw hole of a conventional stainless rigid plate(RP) to form a stress－ relax-ation plate(SRP). Both SRP and RP were applied to the osteotomized New Zealand rabbit tibia, thefracture healing process of either fixing with SRP or RP(control) was put under comparative study bypolarized light microscopy, in situ hybridization of collagen mRNA and immunohistochemistry tech-nique from 2 to 36 weeks postoperatively. ResultsThe study of plated bone remodeling showed thatthe degree of cortex osteoporosis beneath the plate was similar between the SRP and RP group 12 － weekpostoperatively. The organization of the bone structure in the SRP group happened later and milder thanthat of the RP group, and the repair process began 12 weeks after implantation. So the resorption cavi-ties became smaller and the structure of collagen fibers became well oriented along, and the osteoblastslying on the surface of resorption cavities expressed and synthesized type Ⅰ collagen 8 to 12 weeks afterimplantation. The changes above increased significantly in most cavities by 36 weeks. No expression andsynthesis of any kind of collagen could be observed during 12 to 36 weeks after implantation in the RPgroup. ConclusionWithout removal of the bone plate, the SRP fixation not only reduces the degreeof plated bone osteoporosis, but also makes the disorganized bone structure return to normal by the ex-pression and synthesis of type Ⅰ collagen mRNA of osteoblasts lying on the surface of resorption cavities.
