【作者】 吴立东；

【导师】 杨迪生；

【作者基本信息】 浙江大学 ， 外科学， 2002， 博士

【摘要】 全髋置换非骨水泥股骨柄假体髓腔准备的精确性研究 研究目的 观察非骨水泥股骨柄假体在股骨近端髓腔中与骨组织的接触情况及使用机器人辅助手术与传统手术结果的比较。 背景资料 全髋关节置换手术给严重髋关节病变的患者带来了革命性的治疗。全髋置换术的目的是缓解疼痛，有良好活动范围的稳定关节及维持或调节肢体的长度。早期骨水泥技术固定的股骨柄假体因无菌性松动出现失败是很常见的，随访结果显示很高的无菌性松动和翻修率，尤其在年轻和爱好活动的病人中翻修率更高。骨水泥股骨柄的高失败率这使人们开始发展非骨水泥固定方法。70年代中期有关丙烯酸骨水泥固定股骨假体的问题逐渐表现出来。机械性松动和有时伴有骨水泥碎裂的广泛骨丢失是最为关键的问题。由此，人们进行了大量实验及临床研究以尽量减少骨水泥的使用，并提出了股骨假体生物固定的方法。主要处于如下考虑：骨水泥固定假体的高松动率，骨水泥假体固定后的股骨近端应力遮挡所致的骨丢失。传统的非骨水泥股骨柄假体的髓腔处理采用髓腔锉，用梅头来撞击髓腔锉末端完成髓腔准备。理论上说这样的操作适合于植入骨水泥股骨柄假体，而对于非骨水泥柄的髓腔处理则不够理想。所以早期的非骨水泥股骨柄结果不理想，主要的问题是术后大腿痛，术中股骨骨折，及骨长入假体表面失败。在认识到了这些问题后，非骨水泥股骨柄假体得到了许多改进，包括假体材料的改进；假体更适合于股骨髓腔，如股骨柄大小型号的增加，假体模板的测量，解剖型股 骨柄假体：手术器械的改进；手术技巧的提高；假体表面的处理以促进骨组 织的长入等等。非骨水泥型全骸关节置换术己经为骨科医师所接受，并且在 年轻和好动病人中越来越多地应用”“’。非骨水泥型假体的固定多数依赖于 金属假体表面的骨长入。骨长入的两个先决条件是手术时假体获得即刻稳定”及假体表面与活性宿主骨的密切接触。为了得到这些要求，所设计的假体必 须尽可能紧密地填充股骨近端的髓腔。即使这样也仍需对股骨髓腔作一定程 度的修整以精确地适应将要植入的假体柄。换言之，对假体类型和大小的选t择以及手术方法和手术器械操作等均需比使用骨水泥固定假体时更精确。许 多文献指出非骨水泥股骨柄假体与股骨的密切匹配、贴合非常重要。理想的 股骨假体植入应与周围骨组织密切接触，假体与骨组织间没有缝隙存在。这 样假体与骨组织间没有纤维组织长入，可以确保假体表面的骨长入而得到永 久的假体稳定．骨与假体接触的面积越大，负荷就能以较大的面积、均匀地” 予以分散，可更好地接近股骨的正常应变模式，从而有利于长期固定及可减 少大腿痛的发生。 对于骨科医师来说，利用现有的器械精确地做股骨髓腔准备有较大的难 度。因为没有有效的工具来执行股骨髓腔的精确切骨。在工业上，准确和精 确地操作模具的几何形状是机器的特长。骨科机器人辅助手术系统的使用是 为了改进传统关节置换的不足，准确地行股骨髓腔准备。本研究所用机器人 辅助手术系统名为CA S PAPAK爬omnu比r AN叨9UIgk刊pl。lug And卜Ob巾巾， M8queL Germany）。本研究的目的是为了观察非骨水泥股骨柄假体在股骨近 端髓腔中与骨组织的接触情况及使用机器人辅助手术与传统手术结果的比 较。 材料与方法 取10个新鲜成人尸体股骨标本随机分成H组。首先经常规互线检查排 除有外伤，畸形及严重骨折疏松。第一组（5个股骨标本）为对照组，采用甲 传统非骨水泥技术的手术方法行股骨近端髓腔准备后植入股骨柄。第二组为，丁 实验组，使用机器人辅助手术系统帮助植人股骨柄。系统由德国OrtO－MaqUot 公司提供，所用机器人辅助手术系统名为 CASPAR（OmPU Aided Sugical Plwt And RObottes，MMueL Germmp。所用股骨假体均为 osteolock型柄 －2— （OsteolocK Howmedieq Ruthefford，NJ）。，为无领、锥形、非多孔表面组合 式挤压配合型柄。设计参照近端固定理论，带有近端三分之一羟基磷灰石涂 层，避免应力遮挡。远端有袖套，可在不增加柄整体直径的情况下选用以使 柄尖端置于髓腔中央，以避免柄的末端伯心放置，顶着髓腔的骨皮质，引起－术后大腿痛。 第一组的操作程序包括：（）术前常规拍摄标准位前后位及侧位X线更多还原

【Abstract】 INTRODUCTIONCementless total hip arthroplasty (THA) has become an accepted part of the orthopaedic surgeon’s choices and is being used with increasing frequency as an attractive alternative to conventional cemented prostheses especially in young and active patients. However, some problems still remain after cementless THA, such as clinically or roentgenographically visible failure, intraoperative fracture and persistent thigh pain.Clinical researches found that failures of cementless THA arose mainly from the micromotion of the implant and inadequate femoral canal filling and apposition between bone and prostheses. The mechanical strength between the bone and prosthesis interface is positively related to bony ingrowth into the implants. The bony ingrowth into the implant is dependent upon the initial stability of the prosthesis and the close apposition to the bone after implantation. Stability is one of the most important factors for fixation of an implant. Initially, postoperative stability for an implant without cement is dependent upon the ’press-fit’, while the permanent stability for an implant is determined by the bone ingrowth into the component. The interface between the implant and bone may play an important role in affecting early implant stabilisation, possibly by influencing tissue healing dynamics. Minimising the micromotion of the cementlessprosthetic components is a key requirement for obtaining bone ingrowth. Great efforts were made to enhance prosthetic stability, including better designs of the component, using newer materials and treating the surface of components, and modification of the operative technique. These improvements can reduce the motion of implant and osteolysis, improve proximal femoral fixation to prevent stress shielding, and promote bone ingrowth. The second important factor for fixation of an implant is the match of the bone and the prosthesis梩he femoral component should fit the femur or the femoral cavity should be precisely prepared for the component to be inserted in order to make bone ingrowth easily and load transfer properly. Both of them had been already emphasised in theoretical, experimental, and anatomic studies. The quality and quantity of bone ingrowth into the precisely fitting prostheses is different from that of the bad ones. The ingrowth process is facilitated if a satisfactory fit for the prosthesis is achieved during operation, while the spaces between the implant surface and the surrounding bone reduce implant stability and adversely affect the amount of bony ingrowth and the rate of which it occurs.The conventional way to prepare the femoral cavity for the femoral stem is to apply impact loads to a broach with a hammer. The cementless prosthesis is ’press fit* into a slightly undersized canal within the femur. Theoretically, the classical technique of preparing the femoral canal is for cemented prosthesis, it is not ideal for cementless implantation. A common complaint from patients with cementless THA is thigh pain. Engh et al have described 2 types of thigh pain. The first, which occurs in patients with undersized stems, is attributed to micromotion from fibrous stabilisation of the stem. The second comes from patients with good canal fill and osseous hypertrophy around the tip, who often complain mild delay in onset due to stress transfer. ?Some others also found out that the thigh pain is related to the fit and load transfer of the component within the proximal femur. Implants that do not fit precisely are more likely to be associated with residual pain than prostheses that fit more exactly. The fit includes two problems: the implant should fit the femur well (the problem of the femoral prosthesis), and the bone should also be shaped accurately to fit the implant (operative techniques and instruments).Many problems related to cemnetless THA could be alleviated by more precise preparation of the femoral canal and selection of an appropriately sized prosthesis as suggested by many authors. If an ideal contact is established directly between更多还原