DHS与股骨近端锁定解剖钢板治疗股骨粗隆间骨折的疗效比较

股骨粗隆骨折在骨科中是一种常见的骨折,尤以老年人居多,据国内外报道,在美国为0.034%,瑞典为0.035%.此类骨折的病死率较高,大约10%～20%的患者在骨折后1年内死亡[1].本院自2005年7月至2008年6月,收治股骨粗隆间骨折病人36例,选取了DHS和股骨近端锁定钢板内固定各18例,进行回顾性分析,进行了疗效的对比.

Objective: To study the influence of stress-relaxation plate on disorganization and repair of the cortex beneath the plate.Methods: A washer made of viscoelastic polyethylene was placed between the screw and the screw hole of conventional stainless rigid plate (RP) to produce a stressrelaxation plate (SRP). Both SRP and RP were applied to osteotomized tibia in 48 New Zealand rabbits. Healing process of the fracture with either SRP or RP fixation (control) was comparatively studied with polarized light microscopy, in situ hybridization of collagen mRNA and immunohistochemical technique from 2 to 36 weeks postoperatively.Results: The study of plated bone remodeling showed that the degree of cortex osteoporosis beneath the plate was similar between the SRP and RP group within 12 weeks postoperatively. In comparison, the disorganization of bone structure in SRP group happened later and milder than that of RP group, and the repair process began at 12 weeks after implantation. As a consequence, the absorption cavities became smaller and the structure of collagen fibers became well oriented along with these changes by polarized light microscopy. In addition to these, the in situ hybridization analysis of collagen genes and the immunohistochemical study of type Ⅰ , Ⅲ collagen showed that the osteoblasts lying on the surface of absorption cavities expressed and synthesized type Ⅰ collagen at 8 to 12 weeks after implantation. From this time on, the changes above became more evident significantly before most of cavities were repaired by 36 weeks. In contrast to the changes in the SRP group, no expression and synthesis of any kind of collagen could be observed during 12 to 36 weeks after implantation in RP group.Conclusions: Without removal of the bone plate, the SRP fixation not only reduces the degree of plated bone osteoporosis, but also makes the disorganized bone structure restored to normal in terms of the expression and synthesis of type Ⅰ collagen mRNA of osteoblasts lying on the surface of absorption cavities.