拱形交叉固定接骨板的生物力学研究

目的 报告拱形交叉固定接骨板与另外两种接骨板生物力学试验结果。方法 以南种材质拱形板、矩形板,应力型板进行四点弯曲电测量,三点弯曲、循环拔钉及扭转拔钉和冲击对比试验。结果 电测试验,拱形板中央应力值最小,抗弯强度最大;三点弯曲试验,拱形板强度极限最大;循环拔钉试验,拱形板开始拔钉循环次数最多;扭转拔钉试验,拱形板拔钉时,扭矩、扭转角最大;冲击试验,拱形板冲击韧性最高。结论 拱形板抗弯、抗扭强度及防     

拱形交叉固定接骨板的设计与应用分析

目的 自行设计拱形交叉固定接骨板,报告此板抗弯、抗扭强度及防拔钉和抗冲击能力。方法 对3组同种材质拱形板、矩形板、应力型板进行四点弯曲电测量、三点弯曲、循环拔钉及扭转拔钉和冲击对比试验。每组15块,每个试验用3块。结果 电测试验,拱形板中央应力值最小,抗弯强度最大;三点弯曲试验,拱形板强度极限最大;循环拔钉试验,拱形板开始拔钉循环次数最多;扭转拔钉试验,拱形板拔钉时,扭矩、扭转角最大;冲击试验,拱形板冲击韧性最高。结论 拱形板抗弯、抗扭强度及防拔钉和抗冲击能力最高,克服弯板、断板、拔钉能力强。     

低弹性模量接骨板固定股骨干骨折的有限元分析

目的 探讨不同弹性模量接骨板内固定对股骨干骨折应力及其分布的影响. 方法采用64排螺旋CT对一名健康成年男性股骨进行层厚为0.5 mm的扫描,获得股骨CT数据,再通过软件三维反求得到股骨有限元模型.模拟股骨中段骨折模型,分别采用Ti-6Al-4V(高弹性模量组,弹性模量为110 GPa)和Ti2448(低弹性模量组,弹性模量为30 GPa)两种材料的8孔接骨板进行固定.分析两种不同弹性模量接骨板内固定在轴向压缩、四点前后弯曲和扭转载荷下股骨的应力分布情况,并以应力云图的方式直观地显示应力分布规律. 结果在3种载荷下,两组均在断端接触部位出现最大应力.在轴向压缩载荷下,低弹性模量组最大应力值为30.00 MPa,大于高弹性模量组(21.68 MPa);螺孔内最大应力值(11.47 MPa)小于高弹性模量组(13.89 MPa),应力云图显示:高弹性模量组骨组织呈多个应力梯度分布,而低弹性模量组骨组织应力分布较均匀.在四点前后弯曲载荷下,低弹性模量组最大应力值为11.23 MPa,大于高弹性模量组(7.96 MPa).在扭转载荷下,两组股骨应力分布均较均匀,低弹性模量组最大应力值(63.82 MPa)大于高弹性模量组(43.97 MPa),螺孔内最大应力值(11.47MPa)小于高弹性模量组(31.24 MPa). 结论低弹性模量接骨板内固定股骨干骨折,其骨折断端应力刺激增大,螺孔内应力集中减轻,接骨板的应力遮挡效应减小.     

角形接骨板治疗长骨干骨折643例综合分析

通过对10家医院应用角形接骨板治疗长骨干骨折643例分析,随访521例,除2例延迟愈合、1例骨不愈合、2例深部感染、1例骨髓炎.均在10～24周内获骨性连接.接骨板与螺钉除1例断钉2枚,7例7枚螺钉与接骨板接触部出现轻度锈蚀外,接骨板无一例发生弯曲或折断.骨质除高龄患者外未发现明显应力遮挡现象.结果说明,角形接骨板按材料力学惯性矩原理设计、符合骨折内固定生物力学要求,有较强的实用价值.     

应用角形接骨板治疗长管状骨骨折36例体会

四肢长管状骨骨折在临床中极常见.采用矩形加压接骨板或普通接骨板内固定后文献报道其并发症发生率达11%—85%,这包括接骨板弯曲、拆断、拔钉、断钉、骨不愈合、骨畸形等.我院自1991年3月—1994年12月应用角形自身加压接骨板(简称角形接骨板)治疗四肢长管状骨骨折36例,效果满意.     

两种肋骨固定方式的三点弯曲试验研究

目的通过爪形接骨板与自制＂钛夹＂固定式接骨板对破坏肋骨片段进行固定,进行力学测试,比较两种内固定方式的差异。方法对6具成人男性尸体胸廓标本编号。沿肋骨长轴方向于肋结节（0%）至肋软骨接合点（CJJ点,100%）,每具尸体胸廓取双侧第4、6、8肋骨,截取含50%位点的长约130 mm的肋骨片段用于测定侧区力学。共取得36段肋骨片段,分别编号。将肋骨片段分别置于电子万能力学测试仪上,跨距设为100 mm,加载速度设为2.5 mm/min,进行三点弯曲试验直至标本破坏,记载位移分别为2、4、6、8、10、15、20 mm时的载荷及最大载荷,描绘载荷-位移曲线。然后将上述肋骨片段分为2组,分别用＂钛夹＂固定式接骨板（钛板组）和爪形接骨板固定（肋骨爪组）,于上述加载条件下行三点弯曲试验直至标本破坏,记载相关数据。结果固定前钛板组与肋骨爪组第4、6、8肋骨在最大载荷、峰值形变上差异均无统计学意义（P〉0.05）。肋骨爪组固定前、后第4、6、8肋骨的最大载荷、峰值形变差异有统计学意义（P〈0.05）;钛板组固定前、后第4、6、8肋骨的最大载荷、峰值形变差异也有统计学意义（P〈0.05）。固定后肋骨爪组与钛板组第4、6、8肋骨在最大载荷上差异有统计学意义（P〈0.05）,峰值形变差异无统计学意义（P〉0.05）。结论相比爪形接骨板,＂钛夹＂固定式接骨板固定骨折肋骨后有更稳定的强度。     

新型可吸收接骨板与钛板治疗掌骨骨折的生物力学和临床疗效对比

可吸收接骨板具有无需取出内固定手术的优势。作者对比了一种新型可吸收接骨板与钛板的生物力学特点,发现可吸收接骨板的弯曲强度和刚度与钛板相当,扭转强度可吸收接骨板高于钛板。     

应力松弛接骨板对骨折愈合影响的生物力学研究

目的　明确应力松弛接骨板体内应力遮挡率变化及其对骨折愈合力学性能的影响。方法　将兔两侧胫骨干横形截骨后 ,分别以应力松弛接骨板 (Stress—relaxationplateSRP)和传统坚硬接骨板 (RigidplateRP)固定 ,观察其应力遮挡率变化及愈合骨力学性能变化。结果　两组固定初期 ,应力遮挡率均在 70 %左右 ,此后 ,SRP组随着固定时间延长 ,应力遮挡率逐渐下降 ,8周后 ,明显低于RP组 ;与此相应 ,愈合骨力学性能也逐渐增加 ,至 48周达到正常骨的 93 6 3%。RP组 ,2 4周后愈合骨力学强度逐渐下降 ,48周时 ,最大三点弯曲强度仅为正常 5 7 95 %。结论　应力松弛接骨板体内应力遮挡率的下降与固定时间具有良好的相关性 ;应力遮挡作用的减弱 ,促进了愈合骨力学性能的恢复。     

异体骨接骨板联合不同螺钉治疗股骨干骨折有限元分析

目的对比分析异体骨接骨板分别联合可吸收螺钉(聚-DL-乳酸)和钛合金螺钉(Ti-6Al-4V)治疗股骨干骨折的应力分布情况,验证可吸收螺钉的强度,为临床提供力学依据。方法利用螺旋CT扫描股骨,将扫描数据以DICOM格式导入mimics软件中,建立股骨三维模型。在proe5.0中建立接骨板模型和螺钉模型(简化为圆柱),装配完成后,导入ansys12.0划分网格、材料赋值,并施加700 N轴向载荷、15 N·m弯曲载荷、15 N·m扭转载荷。结果在三种载荷下6根可吸收螺钉最大主应力的最大值为5.75 Mpa、6根钛合金螺钉最大主应力的最大值为24.9 Mpa;两种不同螺钉固定下,股骨和接骨板的应力分布基本相同。结论可吸收螺钉适应于同种异体骨接骨板的固定,与钛合金螺钉相比,具有减少骨头螺钉孔处的应力遮挡的优点。     

MIPPO技术下胫骨近端骨折LCP固定的三维有限元研究

目的 比较胫骨近端内侧LCP接骨板通过锁定孔和加压孔固定在不同载荷下的应力分布特点,探讨锁定固定和加压固定的优缺点.方法 建立胫骨近端骨折LCP接骨板锁定固定和加压固定的三维有限元模型,采用有限元分析法,分析模型在轴向加压、三点侧弯、扭转状态下的应力分布.结果 ①LCP接骨板在锁定固定和加压固定下,都在骨折处和骨折近端第一个锁定(加压)孔处有应力集中现象;②LCP接骨板锁定固定应力均值大于加压固定.结论 锁定固定和加压固定都使钢板在骨折处和接骨板第一个锁定(加压)孔处容易发生断裂,加压固定比锁定固定更稳固,但锁定固定更符合BO理论要求.     

叉型股骨自锁髓内钉治疗股骨骨折的生物力学研究

目的 对叉型股骨自锁髓内钉(Tridentate self-locking intramedullary femoral.nail,TSIFN)力学性能进行实验研究,为临床应用提供依据。方法 采用8具成人新鲜尸体股骨标本进行应力分析实验。比较用TSIFN、梅花钉、Orthofix公司生产的第三代交锁髓内钉固定的股骨骨折在抗压、抗弯、抗扭强度、刚度及其系统承载能力等方面的差异性。结果 实验结果表明:TSIFN在抗压、抗弯、抗扭强度和刚度及其系统承载能力均优于梅花钉内固定(P<0.05)。与Orthofix交锁髓内钉两者无显著性差异(P>0.05)。结论 TSIFN不但生物力学性能优越,强刚度符合生物力学要求,而且应力遮挡小,远端毋需交锁,弹性固定,固定牢靠,能加速骨折愈合,且手术操作简单,便于推广应用。     

"H"型拱桥式接骨板治疗股骨干骨折

目的：探讨“H”型拱桥式接骨板治疗股骨干骨折的临床应用效果。方法：随机选取62例股骨干骨折患者，复位后均采用“H”型拱桥式接骨板固定。结果：随访59例，随访时间4个月-3年，均达到骨折愈合，无并发症发生。结论：该接骨板设计符合生物力学原理；有利于骨折的愈合：其鞍状结构与管状骨固定时呈切线贴敷，可减少因压迫导致的骨坏死；钢板间的拱形连接和螺钉的交叉固定，可增强骨折断端的抗弯及抗旋转能力，其稳定性使患者术后早期即可进行功能锻炼，具有一定的临床应用价值。     

Effect of plate position relative to bending direction on the rigidity of a plate osteosynthesis. A theoretical analysis

Mechanical unloading of the plated bone segment is observed after plate osteosynthesis because the implant takes over a part of the physiological loading. Strain reduction in the bony tissue depends on the rigidity of the plate (cross-sectional area, geometrical form, and modulus of elasticity). The aim of the present study was to calculate theoretically the effect of plate position relative to bending direction on the overall bending stiffness of the composite system plate-bone. To calculate the rigidity, a cylindrical bone model with mechanical characteristics similar to a sheep tibia and a rectangular plate cross-section corresponding to a DC-plate with either a modulus of elasticity of steel or titanium was used. Calculations under different bending directions were performed according to the laws of the linear bending theory and the composite beam theory. The bending stiffness of a plate osteosynthesis reaches a minimum and a maximum respectively, in cases in which the bending moment acts in the direction of the main axis of the area moment of inertia of the plate. The minimum is present with the plate bent vertically, the maximum with the plate bent horizontally, e.g. on the tension side of the composite system--on the assumption that the bone structure opposite the plate is capable of withstanding compressive loading. For steel and titanium plates, factors of 2 and 2.25 respectively were calculated between the minimum and the maximum bending stiffnesses of the osteosynthesis. The bending rigidity of the plate alone has only a minimal effect on the total stiffness of the osteosynthesis. With a plate bent vertically, the difference between steel and titanium plates was 18%, with the plate bent horizontally (situated on the tension side), it was only 7%. The bending stiffness of a plate osteosynthesis depends on the cross-section, the geometrical form, and the modulus of elasticity of the plate, as well as on the plate position relative to the bending direction of the composite system. The modulus of elasticity of the plate is relatively unimportant, while with a given plate the individual plate position relative to the bending direction is of crucial importance. Thus, changing the modulus of elasticity of the plate cannot solve the problem of implant induced unloading of the bone cortex because the bending stiffness of the composite system depends much more on the plate position relative to the bending direction.     

半梅花形钢板的研制及应用

作者自1992年11月应用自行研制的半梅花形钢板治疗四肢骨干骨折47例49处,随访2年8个月,取得了满意的疗效.该钢板厚度1.5mm,其板体全长中央空虚,截面三个半圆曲线呈半梅花形状,具有弹性,经力学测试抗弯抗扭性能比普通钢板强3倍.以钢板两侧块压于骨胳上,似“马钉”样持住骨折端,能有效地控制移位和旋转,而且钢板接触骨面少,改善了板下皮质骨血液循环,降低骨量丧失,减小应力遮挡作用及减轻板下皮质骨疏松程度.为临床提供一种新型半梅花形接骨板.     

三种固定股骨粗隆间骨折材料的临床应用与测试（附62例报告）

目的了解三种应用于股骨粗隆间骨折的内固定材料的抗弯能力,及其对股骨粗隆至股骨头内骨小梁的损伤程度。方法使用型号为MTS810试验机对三种内固定物进行抗弯试验,用量筒测量三种内固定物近端体积。在近端臂体积的测量中,分为近端全长及近端50mm的体积测量。结果在抗弯试验中麦氏鹅头钉平均承受压力为44.61kg,130°角钢板平均承受压力为81.53kg,加压滑动鹅头钉(又称动力髋螺钉,Dynamichipscrew,DHS)平均承受压力为277.43kg。在近端臂的两部分体积测量中,麦氏鹅头钉与130°角钢板体积较小。结论麦氏鹅头钉的抗弯力最小,承重能力最小。患肢不能早期负重功能锻炼,DHS抗弯力最大,承重能力最大。患肢可早期负重功能锻炼。130°角钢板介于二者之间。而麦氏鹅头钉及130°角钢板近端体积小,表明对粗隆至股骨头间骨小梁损伤小。而DHS损伤大。     

An experimental study on various internal fixations in fracture of a long bone (author's transl)

In the operative treatment of a long bone fracture, the most important point is to secure the bone healing and to strengthen the bone after removal of internal fixation materials. In this regards, the author has analyzed the mechanical strength of various internal fixation methods (a plate, a medullary nail, screws and encircling wires) on the bone by using acrylics models. Experimental studies of their influences on the bone have also been performed especially investigating the decrease in the bone strength in rabbits. All of internal fixation materials are made of 316L stainless steel. Recently, there has been a tendency to use larger materials for internal fixations such as an AO compression plate or a Küntscher type medullary nail. However, it was found that the rigid plate fixation greatly affects the bone strength. A medullary nail produced less impairment to the bone. But this method is restricted in its application because of the weak fixability of the torsional load. On the other hand, the internal fixations with screws or encircling wires are weaker than the other methods especially against the bending load. Therefore the commencement of postoperative treatment will be delayed. But, these two methods have little influence on the bone during fixation.     

双矩形髓内钉与加压钢板治疗肱骨干骨折的生物力学比较及疗效分析

目的 通过双矩形髓内钉和加压钢板两种不同内固定物治疗肱骨干骨折的生物力学对比，探讨有利于肱骨干骨折后的骨修复的内固定方法。方法 以成人尸体湿骨制备骨折模型，随机用双矩形髓内钉和加压钢板两种方法固定后进行四点弯曲试验、扭转试验和拉伸试验，并结合临床疗效分析。结果 测试数据经统计学检验，矩形髓内钉组的四点弯曲试验和扭转试验均优于钢板组（P＜0．01），结果有显著差异，而拉伸试验中矩形髓内钉和加压钢板组无显著差异（P＞0．05）。结论 在肱同干骨折的治疗中，对矩形髓内钉固定较加压钢板内固定更适合骨折愈合所需的生物力学环境，且临床效果较后者优。     

Unreamed tibia nail (UTN) bending: case report and problem solution

Background An unreamed tibia nail (UTN), implanted for operative stabilization of the tibia after a distal shaft fracture of the lower leg, was bent by excessive load prematurely applied during the healing process, whereby the cross-section-dependent maximum torque permitted in the edge fiber of the UTN during bending load was exceeded. Straightening of the bent, not broken UTN by hand was impossible. Therefore, the bent UTN could only be removed by causing additional damage to the tibia, which is why bending of the nail must be avoided.Conclusion Our analysis shows that modification of the arrangement of the locking holes by 45° increases bending load capacity of the UTN, which can minimize the probability of the occurrence of a bent nail.     

Verbogener intramedull?rer Tibiamarknagel nach erneutem Trauma

Breakage or deformity of intramedullary nails of the lower extremities is the result of subsequent high energy trauma, falling or noncompliance of the patient in partial weight bearing. We describe the removal of a bent tibia nail in a young patient who sustained another high energy trauma on the same limb. Different surgical options are discussed on the basis of the current literature. Possible removal strategies could be: drilling half diameter of the nail and then straighten it backwards, cutting the nail with a burr or removing the nail without any manipulation of the nail itself. The most customized procedure depends on the available capabilities and the individual case because of the rare occurrence of bent nails. Soft tissue damage, degree of bending and re-osteosynthesis must be considered in individual treatment strategies.