骨水泥阻塞兔骨干髓腔后远侧关节的改变

背景:临床上对骨水泥型人工关节并发症的研究已经很多,但骨水泥型人工关节植入后对远侧关节组织结构的影响仍有待进一步观察。目的:观察骨水泥阻塞兔股骨近中段骨干髓腔后远侧关节组织结构的改变。设计:对照观察。单位:广西壮族自治区人民医院。材料:选用26只健康成年新西兰大白兔,雌雄不拘,体质量2.6～3.5kg,实验动物由重庆医科大学实验动物中心提供。国产聚甲基丙烯酸甲酯TJ骨水泥、16#上颌窦穿刺针(外径1.6mm,内径1.05mm,长80mm)、日本Olympus公司光学显微镜(BH-2型,LM)、日本Hitachi公司透射电子显微镜(H-600,SEM)。方法:实验于2005-07/2006-04在重庆医科大学实验动物中心完成。随机摸球法取18只实验兔为模型组,其余8只不造模,作为对照组。模型组采用兔左侧股骨髓腔内灌注骨水泥进行造模,实验兔麻醉后,采用髋后外方入路,根据兔存在第3转子这个特殊的解剖结构,从股骨后外方肌间隙进入,在第3转子上方仅切除大转子外侧部分而不打断股骨颈,暴露转子间窝,找到骨髓腔入口,用自制的大小合适、粗细不同的髓腔锉反复扩髓后(深度为股骨长度的1/2),反复冲洗创面,冲出破坏的骨髓组织,纱布条蘸干。按粉、液比2∶1比例调配骨水泥,持续手工搅拌,待聚合至面团状态后使用,为避免骨水泥填入股骨骨髓腔后深度无法控制,首先将一小块面团状骨水泥作成髓腔大小塞状物,用器械轻轻填入髓腔内至股骨中段狭窄处,作为髓腔塞,待10min骨水泥基本固化后,再将其重新调配好呈面团状骨水泥,用器械填入股骨髓腔内,直至填满为止。待骨水泥完全固化后,缝合关闭切口,分别于术后4,8及16周取材观察,每次取6只,对照组直接取材,采用苏木精-伊红染色、甲苯胺蓝染色、免疫组织化学检测对两组实验兔实验侧远侧关节软骨、软骨下骨和滑膜组织标本进行组织学观察,同时采用透射电镜观察左侧股骨远端关节软骨、软骨下骨标本组织学变化。主要观察指标:①苏木精-伊红染色、甲苯胺蓝染色、免疫组织化学检测实验兔实验侧远侧关节软骨、软骨下骨和滑膜组织学观察结果。②透射电镜下左侧股骨远端关节软骨、软骨下骨标本组织学变化。结果:①苏木精-伊红染色显示模型组实验兔关节软骨、软骨下骨和关节滑膜组织损害随时间呈进行性加重,造模后16周关节软骨破坏,骨组织结构损害,滑膜组织增生、肿胀;甲苯胺蓝染色显示造模后16周实验兔关节软骨全层失染;免疫组织化学结果:造模后16周软骨细胞Ⅱ型胶原染色阳性,关节滑膜细胞及软骨细胞TGF-β1染色阳性。②透射电镜下模型组实验兔关节软骨和骨细胞损害随时间呈进行性加重,造模16周部分软骨细胞和骨细胞坏死、崩解。结论:骨水泥阻塞股骨近中段骨干髓腔后导致股骨远端血循环障碍,使股骨远端骨代谢发生紊乱,最终造成远侧关节骨、软骨和滑膜组织发生了退行性病变或坏死。

Changes of distal joint after the femoral medullary cavity is blocked with bone cement

BACKGROUND:There are so many researches on the complication of artificial joint of bone cement on clinics, but the effect of implanting artificial joint of bone cement on the structure of distal joint is unclear.OBJECTIVE:To explore the structural changes of distal joint after blocking the proximal and middle femoral medullary cavity with bone cement.DESIGN:Controlled observation.SETTING:The People's Hospital of Guangxi Zhuang Autonomous Region.MATERIALS:A total of 26 healthy adult New Zealand rabbits, of clean grade and both genders,weighing 2.6-3.5 kg,were offered by the Experimental Animal Center of Chongqing Medical University.Polymethyl methacrylate (PMMA) TJ bone cement,16# antrum needle for puncture (outer diameter 1.6 mm,inner diameter 1.05 mm,length 80 mm), light microscope of Japan Olympus Company (BH-2), and transmission electron microscope of Japan Hitachi Company (H-600).METHODS:The experiment was completed in the Experimental Animal Center of Chongqing Medical University from July 2005 to April 2006.Eighteen rabbits were randomly selected as model group,while other 8 ones ware served as control group.The rabbit model was established by infusing femoral medullary cavity of left side with PMMA.Due to the specific anatomic structure of appearing the third trochanter, the anesthetized rabbits were adopted to incise the lateral greater trochanter below the third trochanter through spatium intermusculare of posterior lateral femur, remaining the neck of femur, so as to expose intertrochanteric fossa and entry of medullary cavity,which was expanded to 1/2 length of femur by using cavity file of different thickness repeatedly. Then wound surface was washed fob many times to remove the destroyed myeloid tissues, and was dried with strips. Bone cement was prepared by manually stirring powder with solution at a ratio of 2:1, until it demonstrated dough shape. In order to control the depth of bone cement into femoral medullary cavity, a small piece of dough-shaped bone cement was filled in middle femoral stenosis as cavity blocker.Ten minutes later,the solidified bone cement was re-blended as dough shape and implanted into medullary cavity fully.Afterwards, the bone cement was completely solidified and the incision was sutured. At the 4th, 8th and 16th weeks postoperatively,6 rabbits of each model group and all controlled rabbits were killed respectively to obtain the samples of distal femoral articular synovium, cartilage and subchondral bone. The histological examinations included hematoxyiin-eosin (HE) staining, toluidine blue (TB) staining and immunohistochemistry. Transmission electron microscope was used to detect the changes of cartilage and subchondral bone in distal joint of left femur.MAIN OUTCOME MEASURES: ①The structural changes of distal femoral articular synovium, cartilage and subchondral bone by HE staining,TB staining,immunohistochemistry.②The histological changes of distal articular cartilage and subchondral bone in left femur by transmission electron microscope.RESULTS:①HE staining:The damages to articular cartilage,synovial tissues and subchondral bone aggravated with time.At the 16th week of modeling,the articular cartilage was destructed,the bone structure was severely damaged,with the synovial tissue proliferation and swelling;TB staining (the 16th week):All the layers of articular cartilage appeared loss of stain; Immunohistochemistry (the 16th week): Collagen Ⅱ of the chondrocytes was positively stained. And transforming growth factor (TGF)-β1 staining of articular synoviocytes and chondrocytes appeared positive.②Transmission electron microscope: The lesions to articular chondrocytes and bone cells aggravated progressively with time, part of which presented necrosis and collapse at the 16th week.CONCLUSION: The intramedullary blood circulation is severely damaged after blocking the proximal and middle femoral medullary cavity with bone cement. Conversely, the bone metabolism disorders in dista0 femur. which results in the degeneration or necrosis of distal femur, cartilage and synovial tissue.