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机械臂和手工髓腔准备无骨水泥股骨柄植入后的生物力学测试

The Effect of Surgical Instrumentation on Interface Motion in uncemented Hip prostheses

【作者】 陶惠民

【导师】 杨迪生; 彭淑牖;

【作者基本信息】 浙江大学 , 外科学, 2002, 博士

【摘要】 前言 手术前,无骨水泥股骨柄植入后微动的生物力学测试,能够预示股骨柄中远期生存状况。微动是指髓腔骨面与植入假体之间较小的相对活动。微动的测量可以提供有价值的有关植入假体原始稳定的比较数据。在无骨水泥股骨柄植入股骨髓腔,骨髓腔面与植入假体之间原始稳定为假体表面骨的长入提供了稳定的机械环境。假体表面骨的长入,即所谓的生物学固定或骨连接(ossessintegration)已在体内研究及股骨与植入物复合体的活检得到证实。这种生物学固定或骨连接是植入物在体内长期固定的重要条件。植入物植入后,其原始稳定性越高,骨长入植入物就越稳定,因此,改善植入物的原始稳定应该被强调。在大量临床随访资料中,人们发现,髓腔骨面与植入假体之间的微动超过正常范围将影响骨生长和塑性,从而导致腿痛、假体周围皮质疏松及假体的松动。在实验研究中,Pilliar等发现髓腔骨面与植入假体之间的微动超过150μm,骨不能长入植入物表面结构,而代之以纤维组织包膜。Jasty等在体内试验中证实,骨生长和塑性与珍珠面植入物的微动大小有关。Sobal等发现在不稳定的羟基磷酸钙帽植入物周围有纤维组织包膜形成。无骨水泥股骨柄植入后的原始稳定,受多种因素的影响,植入物形态的设计、术后肢体负重的大小和方式、外科技术和器械的改进、股骨骨床的质量,植入物的材料。“适合和填充”是无骨水泥股骨柄设计原则,也是其原始稳定的前提条件。许多临床和实验,主要集中在如何改善股骨柄形态和表面的设计,而在原始稳定中起重要作用的外科技术和器械的改进,并没有受到足够的重视。1999年初,基尔大学临床骨科,引进了计算机控制的机械臂(CASPAR)来替代人工完成股骨髓腔的准备,至今有30余例患者使用机械臂进行了无骨水泥股骨柄人工全髋置换,这些患者短期X线随访,具有良好的原始稳定。无骨水泥股骨柄的原始稳定是影响无骨水泥股骨柄全髋置换术后长期生存的主要因素,手术前,生物力学测量无骨水泥股骨柄与骨质之间的微动(micromotion)是了解无骨水泥股骨柄原始稳定的最主要参数。很少有文献报道,使用机械臂和人工准备股骨髓腔,是如何影响无骨水泥股骨柄的微动。我们采用合成股骨材料模型替代股骨,分别用机械臂和人工模拟,用于两种不同设计的股骨柄髓腔准备,插入无骨水泥股骨柄后,予以垂直及旋转加载负荷,分别测定垂直及旋转微动。材料和方法 浙江大学医学院 采用(osteoloc,H。edica)和(Mathvs,Depuy)两种无骨水泥股骨 柄,在股骨模型中分别用机械臂及手工器械准备髓腔,人造股骨模型一个 是长方体,测试垂直负荷的人造股骨模型是一个长方体(16 X 15X8cm), 测试旋转负荷的人造股骨模型是一个圆柱体(68cm,L=16cm),其材料是 聚胺脂合成。本研究分机械臂及手工乞腔准备两组,每一组分别用7个人造 股骨模型作为研究对象。 机械口曰腔椎备: 模拟股骨胜及大粗隆置钉:将人造股骨模型固定在操作台的右下角,刚 好将人造股骨模型垂直的两个面与操作台右下角平齐。在操作台的右面。 沿其边,向上置一10 nun宽,45 nun长的固定板,固定板的内面与人造股骨 模型一面相互靠近,人造股骨模型一个面向操作者。在固定板远端,距人 造股骨模型操作面42M处,置两个模拟股骨胜定位钉,距人造股骨模型操 作面2。处,置一个模拟大粗隆定位钉。采用的定位钉均用于人体手术。 这三枚定位钉提供机械臂协调其术前准备与操作模型之间定位关系 机械臂操作:导航系统:在计算机工作站(1咖中,从H。一d让。和k叩。 公司提供的无骨水泥股骨柄osteoloc和athys形态及大小数据库中,分别 挑选2号和10号股骨柄相对应的矢状面、冠状面、横截面的形态,输人计 算机工作站。机械臂系统:机械臂CASPM(ortOMatluet)是由五个轴带有 六个不同程度的自由力矩传感器和一个标推高速(65000-75000_)外科 切割工具的机械臂用于外科手术,能在低速下工作。具有可活动的机械臂 能在任何角度任何位置进行工作,机械臂的工作是在计算机(IWe PC/AT) 控制下进行工作。所有操作均通过遥控器,在电脑显示屏提示下进行。先 进行机械臂空间位置的自动校验,待校验完毕,分别探测三枚模拟股骨骸 及大粗隆置钉,手控下探测每个钛针,当完全探测完毕,机械臂与导航系 统进行协调统一。换上切割工具,就可以进行股骨髓腔的准备。髓腔切割

【Abstract】 The Effect of Surgical Instrumentation on Interface Motion in uncemented Hip prosthesesComparison of CASPAR -system and Convention-manual for Femoral Canal ofPrepareationDepartment of Surgery Medical School of ZheJiang University Ph.D Candidate Tao huiminTutor Yang disheng Peng shuyouMeasurement of micromotion , defined as small relative motion at the interface between bone and implant, can provide valuable comparative data with regard to initial stability. Initial stability at the interface between the prostheses and bone in femora that provides a potential mechanical stable environment for bone ingrowth in uncemented femoral components. Biological fixation or Ossess-integration by bone ingrowth into the prosthesis surface was testifed in vivo studies and history biospy of human femoral bone and implant composite, is generally thought to an important condition, achieve long-term fixation. The highter the initial stability of the implant at time of implanta-tion, the better is the stable ingrowth into the implant. So the important of improving initial stability is emphasised, hi the clinical investigation, Excessive motion at the interface between bone and implant affect bone ingrowth and remodeling, are believed to induce thigh pain, the high incidence of periprosthetic femoral osteolysis and ultim-ately lead to loosening of the implant. In the canine vivo study, Pilliar et al. found that micromotions of the interface is greater than ISOum will inhibit bone ingrowth and lead to fibrous encapsulation of the uncemented implant. Jasty and Harris demonstrated the in vivo patterns of bone ingrowth and remodeling are related with different magni-tudes of micromotion of poroused-coated implanteds. Soballe et al. also found the fibrocartilaginous tissue characterized the membrane around unstable HA(hydroxyapa-tite) implants.Thus the initial stability achieved by implant inserted without cement, will be affected some important factors, such as the improving of the surgery techniques and instrumentation, the design of the implant, the load of the implant postoperation, the quality of the femoral bone bed and the material of the implant. In the design principle of the implant, Fit and fill between the prostheses and bone in femora is prerequisite for achieving initial stability. However, many experimental and clincal studies forcus on how improved the design of the implant and the structure of the implant surface, to fit and fill for the different femoral canal geometries in the control of micromotion at the interface. On the other hand, operational technique and surgical instrumentation, as used to prepare femoral canal, plays an important role in initial fixation, is improved how to fit for the different design of the implanst better, is not still emphasised.The conventional surgery techniques and instrumentation that can not ensure initial accuracy contact between the prosthesis and bone. In order to achieve optima] initial fixation of the implant, robot-assisted (CASPAR) implantation of the cementless implant has been performed in orthopedical clinic in Kiel universtry since 1999. Preoperative planning and data from analysis of CTimage at a three-dimensional graphic work station, are transferred to the robot, which transforms the preoperative planning and date by milling the femoral cavity with the highest precision. The CASPAR -system is thought to be safe and effective- in producing radiographically superior implant fit and fill while eliminating femoral fractures.Postoperative followed-up results are satisfaction with achieving initial stability of the cementless implant.Few experimental studies have examined how prepared the femoral canal through CASPAR -system and Convention-manual affect micromotion of the femoral implant To measure the extent of these three-dimensional movements, an in vitro synthetic composite model femora method for measurement of the micromotion of the femoral component of hip prostheses in the same femoral condition has been developed. Com-pari

  • 【网络出版投稿人】 浙江大学
  • 【网络出版年期】2002年 02期
  • 【分类号】R687.3
  • 【被引频次】1
  • 【下载频次】137
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