人工髋关节界面的应力研究进展

自从1938年Phillip Wiles施行第一例全髋关节置换术以来,在假体的设计、工艺、材料,以及手术技巧方面有了很大的改进和发展。然而,人工髋关节置换术尚有许多不足之处有待进一步改进,其中假体松动是公认的手术失败的最主要原因之一[1]。近年来的研究表明,假体周围的骨溶解是引起人工关节松动的最主要原因。引起假体周围骨溶解的原因及其发展过程尚未完全清楚,但其致病原因可归纳为两大主要因素:一为生物学因素,即骨溶解由磨损颗粒引起;另一为机械因素,即骨溶解由应力遮挡、关节液压力、假体固定不牢等引起。当假体植入骨组织内,假体与组织之…     

人工髋关节假体摩擦界面的进展

20世纪60年代Jone Charnley根据髋关节低摩擦生物学原理,提出金属股骨头和聚乙烯髋臼组合获得巨大成功,一度成为衡量其他关节关节置换手术的金标准。随着全髋关节置换术的广泛开展,人们逐渐认识到影响人工关节寿命最主要的原因是假体无菌性松动[1],其最常见的发生机制是关节假体磨损产生的颗粒导致的骨溶解,文献报道最主要的磨损颗粒是聚乙烯颗粒[2]。为了改善传统超高分子量聚     

髓腔改变对股骨近端假体-骨界面应力的影响

目的 建立股骨近端假体-骨界面应力有限元分析模型.并对中国成年人股骨近端正常受力、翻修过程中扩髓条件下进行静态有限元分析.方法 运用逆向工程与有限元的理论.对CT图像采用了滤波、边界提取、二值化等方法进行处理,所得数据用CAD软件经过曲线重构、曲面重构、实体重构,加工出股骨应力模型.将不同载荷施加与假体-骨界面,改变股骨骨皮质的厚度、假体长度等参数,进行静态模拟应力分析.结果 建立起以国人股骨为基础的有效的假体-骨界面应力分布规律三维有限元模型.股骨的受力主要集中在小转子和大转子之间的股骨距分布区域,并且随着载荷的增加而递增;假体增粗至原来的120%时,股骨最大应力已经接近极限应力值.结论 构建的解剖型股骨假体-骨界面三维有限元模型,几何相似性好.模拟应力分析结果提示接受关节置换的患者应该尽量避免登山等接近加载量极限的活动;对于髓腔骨缺损严重的翻修患者提倡应用骨移植材料.谨慎采用增粗假体固定.     

非骨水泥全髋置换术中机器人辅助植入假体与人工植入假体效果对比分析

作者对于非骨水泥全髋置换术中机器人辅助植入假体与人工植入假体做一前瞻性对比分析,随访至少5年。结果发现,在术后2—3年,关节JOA评分机器人辅助组略高,而5年之后,两者差异无显著性。机器人辅助组5年后随访双下肢长度差异更小,人工组术后2年应力遮挡效应显著增高,术后5年差异更加具有显著性。     

无柄髋关节是少量应力遮挡的人工髋关节(续)

3少量应力遮挡的人工髋关节(lowstress shielding arthroplasty of the hip)从生理学而言,股骨颈尤其重要,因为人体相关的生物力学主要压应力,主要拉应力,次要压应力,次要拉应力,及大隆间应力共有五道应力,在股骨头颈间汇总后,在股骨颈内交叉后走向股骨干内外侧皮质骨。所以保留股骨颈就等同于保留了股骨颈的生物力学,同样的道理,切除股骨颈就等同破坏     

特制人工髋关节假体在髋部骨肿瘤的应用分析

目的探讨特制人工假体在髋部肿瘤保肢术中的应用价值。方法回顾性分析我院自1999年3月至2005年5月髋部原发肿瘤患者行特制人工假体置换术后疗效、并发症及处理资料。本组肿瘤病例中,髋臼11例,股骨近端15例;肿瘤类型:软骨肉瘤3例,骨肉瘤6例,滑膜肉瘤1例,骨巨细胞瘤12例,良性纤维组织瘤2例,动脉瘤样骨囊肿2例。假体类型:人工全髋关节假体17例,人工双极股骨头7例,马鞍式关节假体2例。结果随访时间为18个月～6年,平均4年3个月;10例恶性肿瘤局部复发率40%,保肢率60%,16例中间性及良性肿瘤复发率12.5%,保肢率87.5%,参照Enneking(MSTS)评定标准平均得分19分,优良率76.9%。结论特制人工髋关节假体具有良好的术后肢体功能,是髋部骨肿瘤较为满意的保肢治疗方法之一。     

Revision prosthesis for the hip joint in severe bone loss

When total hip prostheses loosen after initial implantation and subsequent prosthesis replacement, increasing bone resorption occurs in the bed of the prosthesis. Finally, a very thin cortex remains in the bed of the prosthesis, which no longer provides sufficient mechanical stability. The replacement prosthesis described, which is anchored in the distal medullary canal without cement, provides a bridge over the damaged prosthesis bed and results in a condition of relative mechanical stability. After implantation of the replacement prosthesis, lively proliferation of the bone tissue occurs in the old prosthesis bed, which again replaces the bone loss that had taken place previously. The late results that would permit a final assessment of the procedure are not yet available.     

老年骨质疏松症人工髋关节置换术后假体松动的预防

目的寻找(探索)股骨颈骨折人工股骨头置换术后防止假体松动下沉而引起的髋部疼痛的治疗方法。方法将38例骨质疏松性股骨颈骨折行人工股骨头置换术后患者分成两组,每组19例,一组术后给予治疗骨质疏松的药物,即益钙宁20 U/支,每周1支,肌注。维生素D3(阿法骨化醇)1.0μg/日,口服。钙尔奇D 600 mg/片,每日1片,口服。另一组不给治疗骨质疏松的药物。术后一年随访,有无髋部疼痛和再发骨折。结果给予药物治疗组只有一例因股骨头型号太大而疼痛。拍双髋X光片见骨密度与手术时拍的X光片比较无明显变化。亦无假体松动和下沉现象,更无再次骨折的发生。没有给治疗骨质疏松药物组19例髋关节皆有不同程度的疼痛;双髋X光片见骨密度减低,而且假体松动下沉。还有两例发生再次骨折。结论 老年人骨折手术后必须同时给予治疗骨质疏松的药物,才能防止骨质疏松的发展及并发症的发生。     

Cone prosthesis for the hip joint

The shape of the proximal segment of the femur must be taken into account when implanting femoral endoprostheses, especially those intended for cementless anchorage. Numerous femoral prostheses are available for the proximally broadly extending, "trumpet-shaped" morphology. However, the femur often has a narrow, more cylindrical configuration, as is frequently seen with dysplastic hip joints, but variants of the anatomical constitution or ethnic variants are also found. Conventional femoral prostheses with a proximal transverse oval or rectangular cross-section are often incorrectly positioned in those cases because they can fracture the narrow bones. In many instances, even a pathological anteversion attachment cannot be adequately corrected. The cone prosthesis is ideal for this morphology when pre-operative planning indicates good contact between the bone cortex and the middle third of the prosthetic stem. The tapered anchorage of the cone stem in the medullary cavity reamed to a cone shape promotes primary stability, which is a fundamental prerequisite for the osseointegration of a coarse blasted titanium implant. The sharp longitudinal ridges on the prosthetic stem, which tend to cut into the bone, ensure extensive rotational stability, which explains why thigh pain is not associated with the cone prosthesis. The cone prosthesis has proved its worth in 635 implants performed over 9 years, with highly satisfactory clinical and X-ray results. The surgical technique is relatively straightforward, and complications are rare. The patients' subjective satisfaction is particularly remarkable. The success of the operation lies in correct preoperative planning, which ensures that the morphology of the selected femur guarantees contact between the bone cortex and the middle third of the prosthetic stem.     

人工关节假体的摩擦学研究进展

人工关节置换术经过近百年的发展,现已成为矫形外科/运动医学领域成熟的治疗技术,在美国以每年超过45万~60万的置换数量呈阶梯式递增。如何提高人工关节假体寿命、减轻术后并发症,是临床工作者及患者共同的期盼。既往学者关注重点多在于人工关节假体感染性/无菌性松动,近年来人工关节的摩擦学研究越来越受到重视。影响人工关节假体使用寿命的关键因素之一在于假体各组成部分之间的磨损问题,特别是由于接触表面的磨损造成表层的损耗进而导致整体/局部力学的改变。然而,假体生物摩擦学是一个复杂的综合性问题,本文将分别对膝/髋关节的摩擦学、假体材料特性、润滑、磨损变化等方面的研究现状和进展加以探讨,以期为临床和基础工作者提供有益帮助。