骨质疏松性骨折愈合与骨量、骨结构及力学性能相关性的实验研究

目的探明骨质疏松性骨折愈合程度与骨量、骨结构与力学性能的相互关系,以期能为临床治疗提供科学指导与理论依据.方法选择8月龄雌性SPF级SD大鼠130只,随机分为2组：骨质疏松性骨折组（OPFM）与一般性骨折组（CFM）,每组各65只.手术方法建立骨质疏松性骨折与一般性骨折的实验模型,于术后1、2、4、6、8、12、16周作骨痂组织形态计量学、骨密度与力学性能测试等观察.结果①骨痂组织骨组织形态计量学结果发现：OPFM组成熟小梁骨占骨痂面积比CFM组小,且小梁骨厚度变薄、小梁骨间距较宽;同时骨小梁动力学参数显示：OPFM组骨小梁表面荧光标记百分比（LS）较CFM组低,而骨矿化沉积率（MAR）却较高.②骨密度（BMD）测定显示：两组BMD值8周时均达到高峰（P＞0.5）,随后均降低,OPFM组下降尤为明显;12周时两组间差异有显著性（P＜0.05）.③骨痂组织扭转力学强度测试结果表明：8、12周OPFM组扭转强度均较CFM组低.结论在骨质疏松性骨折修复过程中,骨痂组织的有机成份组成、显微结构、骨矿代谢与骨量的异常改变导致了其力学强度乃至骨折愈合质量的降低,是再次骨折发生的主要原因.

An experimental study on the correlation of osteoporotic fracture healing with bone mass, bone structure and mechanical strength

Objective To elucidate the correlation of osteoporotic fracture healing with bone bass,bone structure and mechanical strength.Methods One hundred and thirty 8-month-old femal SD rats were randomized into two groups of 65 each:the osteoporotic fracture model (OPFM) and the general fracture group (CFM).The callus of each rat was examined by dual-energy X-ray absorptiometry (DEXA),bone histomorphometry,biomechanical testing in 1,2,4,6,8,12,16 weeks postoperatively.Results Microstructure of callus (bone histomorphometry) showed that the area of mature trabecular in callus of OPFM group was smaller than that of CFM group,and was thinner with a wide intertrabecular distance.The dynamic parameters demonstrated that the fluorescent labeling percentage(LS) on the trabecular surface of OPFM group was lower than that of CFM group,but bone mineral apposition rate (MAR) was higher.Bone mineral density(BMD) manifested that both groups reached the peak point at week 8 (P>0.5) and then declined,especially in the OPFM group.At the 12th week,significant difference was shown between the two groups(P<0.05).The results on torsional testing of callus showed that the torsional strength of OPFM group was lower than that of CFM group at 8th,12th week(P<0.05).Conclusions During osteoporotic fracture healing process,the abnormal change of the organic constitution,microstructure,bone mineral metabolism and bone mass of callus could result in decrease of mechanical strength or quality of fracture healing which might be the main cause of refracture.