In vitro Effects of External Fixation on Intact and Osteotomized Tibiae: A Biomechanical Study

In order to study the in vitro mechanical effects of external fixation on intact and osteotomized bone, human and rabbit tibiae were tested in three-point bending in an Instron testing machine. Intact tibiae were loaded in the elastic range before and after application of an external fixation device. in the human specimens the Vidal-Adrey double frame was used, and in the rabbit specimens the external mini-fixation. the bone deformation in the anteroposterior direction was measured with a linear voltage differential transformer. After application of external fixation a median bone elastic stiffness of 110.2 per cent in human tibiae and of 106.1 per cent in rabbit tibiae was found, in relation to the stiffness of intact tibiae without external fixation. the stiffness increase was significant in human specimens, but not significant in rabbit specimens.

In osteotomized human tibiae fixed with the Vidal-Adrey double frame a median stiffness of 8.5 per cent of the stiffness of intact bones was found when compression was not applied, compared to 19.9 per cent when compression was applied. in rabbit tibiae a median stiffness of osteotomized bones with external mini-fixation was 8.9 per cent of the stiffness of intact bones. There was a good agreement between the results in rabbit tibiae with the mini-fixation and human tibiae with external fixation without compression. the external mini-fixation thus seems to be a suitable model for the study of bone healing in rabbit tibiae.     

Recovery of Diaphyseal Bone Strength After Rigid Internal Plate Fixation: An Experimental Study in the Rabbit

The course of the recovery from the unfavourable effects of a rigid internal fixation plate on the strength of diaphyseal bone, measured as the maximum torque capacity, has been studied in rabbit tibiae. Due attention was paid to the screw holes. on removal of the plate, which had been applied for 12 weeks without prior osteotomy, the bone had decreased in strength by approximately 50 per cent.

Following removal of the plate, the bone regained its normal strength after only 6 weeks. the regaining of strength proceeded in a significantly non-linear manner and in accordance with the logistic function     

Recovery of Diaphyseal Bone Strength After Rigid Internal Plate Fixation: An Experimental Study in the Rabbit

The course of the recovery from the unfavourable effects of a rigid internal fixation plate on the strength of diaphyseal bone, measured as the maximum torque capacity, has been studied in rabbit tibiae. Due attention was paid to the screw holes. on removal of the plate, which had been applied for 12 weeks without prior osteotomy, the bone had decreased in strength by approximately 50 per cent.

Following removal of the plate, the bone regained its normal strength after only 6 weeks. the regaining of strength proceeded in a significantly non-linear manner and in accordance with the logistic function     

改良DICK外固定支架治疗胫腓骨骨折临床研究

目的:采用改良DICK三维微型外固定系统(reformed dick externalfixationsystem ,RDEFS) 对胫腓骨新鲜、陈旧骨折进行治疗。方法:利用脊柱椎弓根内固定DICK 系统的基本原理,同时结合胫腓骨生物力学特性将DICK系统在原有设计的规格上,对钉的形状、长短及支撑杆的长度、直径等进行改良。根据胫腓骨折的类型,张力带分布情况,拟定复位方式、进钉点、角度及操作步骤。采用此方法对65 例新鲜及陈旧胫腓骨骨折进行治疗,同时进行生物力学测定。结果:采用此方法治疗骨折愈合率为100% ,骨折愈合时间:新鲜闭合性骨折32～90 d,平均68 d,开放性骨折50～170 d,平均108 d。陈旧性骨折不愈合57～210 d,平均130 d。结论:改良DICK系统具有三维固定的功能,同时在固定过程中可进行骨折对位的调整,该系统操作简单,调节灵活,体积小,利于患者早期活动。经生物力学测试完全满足胫腓骨骨折固定及促进骨折愈合的需要。     

The Stress-Protecting Effect of Metal Plates on the Intact Rabbit Tibia

The purpose of the present study was to find the extent of stress-protection by a steel plate (45 × 5 × 1 mm) on the rabbit tibia. The animals were sacrificed after 6, 12 and 18 weeks. The median strength after plate application was 84, 73 and 72%, respectively. The elastic stiffness of plated bones was also reduced, while the deformation at fracture showed no significant reduction. The mineral content in the bone segment previously covered by a plate was measured by photon absorptiometry; it was reduced after 12 and 18 weeks. The stress-protecting effect caused by this thin steel plate was less pronounced than that previously reported by groups using more rigid plates on rabbit tibiae. The stress-protecting effect increased up to 12 weeks, but subsequently no further increase occurred.     

The Stress-Protecting Effect of Metal Plates on the Intact Rabbit Tibia

The purpose of the present study was to find the extent of stress-protection by a steel plate (45 × 5 × 1 mm) on the rabbit tibia. The animals were sacrificed after 6, 12 and 18 weeks. The median strength after plate application was 84, 73 and 72%, respectively. The elastic stiffness of plated bones was also reduced, while the deformation at fracture showed no significant reduction. The mineral content in the bone segment previously covered by a plate was measured by photon absorptiometry; it was reduced after 12 and 18 weeks. The stress-protecting effect caused by this thin steel plate was less pronounced than that previously reported by groups using more rigid plates on rabbit tibiae. The stress-protecting effect increased up to 12 weeks, but subsequently no further increase occurred.     

外固定器治疗肱骨干骨折不愈合

目的探讨单侧外固定器治疗肱骨干骨折骨不连的方法及疗效。方法应用单侧外固定器治疗44名肱骨干骨折不愈合的患者,其中37例已采用外科手术内固定治疗。结果全部病例平均于术后4.9个月(3.8~7.1个月)骨折愈合,随访6~23个月,患肢随诊肩肘关节功能良好。结论单侧外固定器治疗肱骨骨折骨不连是一种操作简便、创伤小、并发症少的有效方法,治疗期间肩、肘可早期功能活动。     

骨外固定器行胫骨迁移治疗血栓闭塞性脉管炎的护理

目的 总结利用骨外固定器行胫骨迁移治疗血栓闭塞性脉管是的护理经验。方法 35例血栓闭塞性脉管炎37条患肢应用骨外固定器迁移胫骨治疗。术前积极处理患肢、有效的心理护理，术后严密观察，做好骨外固定器迁移胫骨的护理。结果 2例间歇性跛行距离增加；27例夜间静息痛均得到缓解；7例足趾缺血坏死中除3例术后患肢缺血加重截肢外．余4例患肢供血改善。坏死区域结痂愈合；总有效率91．9％。结论 面、准确地评估患者，完善术前准备及术后正确迁移指导可提高骨外固定器行胫骨迁移治疗血栓闭塞性脉管炎的有效性。     

骨外固定器行胫骨迁移治疗血栓闭塞性脉管炎的护理

目的总结利用骨外固定器行胫骨迁移治疗血栓闭塞性脉管炎的护理经验.方法对35例血栓闭塞性脉管炎37条患肢应用骨外固定器迁移胫骨治疗.术前积极处理患肢、有效的心理护理,术后严密观察,做好骨外固定器迁移胫骨的护理.结果 32例间歇性跛行距离增加;27例夜间静息痛均得到缓解;7例足趾缺血坏死中除3例术后患肢缺血加重截肢外,余4例患肢供血改善,坏死区域结痂愈合;总有效率91.9%.结论全面、准确地评估患者,完善术前准备及术后正确迁移指导可提高骨外固定器行胫骨迁移治疗血栓闭塞性脉管炎的有效性.     

Torsional Strength of Cortical and Cancellous Bone Grafts After Rigid Plate Fixation

Mechanical properties of cortical and cancellous interposition grafts in rabbit tibio-fibular bones fixed with 6-hole DCP/ASIF plates were tested with torsional loading after intervals of 3 to 52 weeks postoperatively.

In the cortical grafts maximum torque moment at fracture, energy absorption capacity and rigidity increased from 3 to 12 weeks, while the cancellous grafts were more plastic with lower rigidity, higher angular deformation and higher energy absorption.

From 12 to 52 weeks maximum torque moment at fracture, energy absorption, rigidity and angular deformation decreased in grafts of both types, the respective means at 36 weeks being 39, 34, 57 and 82 per cent of the control values for the cortical grafts, and 26, 17, 42 and 58 per cent of the control values for the cancellous grafts. The differences between the torsional properties of the two graft types decreased with time.     

应用Hybrid外固定架治疗胫骨远端骨折

目的探讨治疗胫骨远端骨折的有效治疗方法。方法从2000年1月2002年8月，使用hybrid外固定架治疗胫骨远端骨折36例，包括胫骨远端平台骨折和胫骨远端骨折，按照A0分类，A1型3例，A2型3例，A3型3例，C1型6例，C2型12例，C3型9例。其中开放骨折10例，25例(69％)为高能量损伤。结果按照Helfer标准评价，36个病人平均随访14个月，平均愈合时间为5个月，除1例外，全部解剖复位或恢复力线。优12例，良10例，中8例，差6例。12例出现不同的并发症占33％。结论应用hybrid外固定架治疗胫骨远端骨折可以减少手术并发症，比较有效。     

腓骨内固定对胫骨愈合及踝关节稳定的作用

目的：探讨腓骨内固定的理论依据。方法：总结３０５例胫腓骨骨折双内固定的骨折愈合情况。结果：３０５例胫腓骨骨折病人除２例延迟愈合外全部愈合。本组骨折愈合率明显高于文献中记载。结论：（１）腓骨内固定后有益于胫骨内固定的稳定。（２）恢复了腓骨的解剖连续,促进踝关节的稳定。（３）提高胫腓骨双骨折病人的骨折愈合率。     

外固定架治疗胫骨多段骨折

目的：对外固定架治疗胫骨多段骨折的效果进行总结。方法：本组27例胫骨多段骨折，采用单侧型Hoffmann外固定架固定，观察临床疗效。结果：骨折愈合率为88．9％，平均愈合时间为62个月，优良率为88．89％，结论：外固定架对各种胫骨多段骨折均适用，尤其是开放性骨折。     

切开复位单边外固定架固定治疗胫骨干骨折

目的探讨单边外固定架固定治疗闭合性胫骨干骨折时采用切开复位的临床效果。方法选择120例胫骨干闭合性骨折的患者，在条件尽可能相近的情况下分为两组，每组60例，一组采用切开复位，另一组采用闭合复位，复位后两组均使用单边外固定架固定。术后随访一年半。对其复位情况、骨折愈合情况、钉道及局部感染以及手术所用时间进行分析，并做统计学处理。结果切开复位组的解剖复位率明显高于闭合复位组（P〈0．01），骨折愈合两组无统计学上的差异（P〉0．05），钉道及局部感染情况两组相似，切开复位平均所用时间较闭合复位短。结论在使用单边外固定架固定治疗胫骨干闭合骨折时采用切开复位是一种很好的方法。     

外固定支架与皮下前环内置外架治疗骨盆前环骨折疗效比较

目的探讨骨盆前环外固定架固定(anterior pelvic external fixation,APEF)与皮下前环内置外架(internal anterior fixation,INFIX)治疗骨盆前环骨折的临床疗效。方法回顾性分析2015年1月至2019年1月由河南省人民医院骨科收治的61例骨盆不稳定骨折的患者资料,根据治疗方式分为两组:APEF固定组30例,其中男17例,女13例;年龄36~58岁,平均为(46.2±2.2)岁。骨盆骨折根据Tile分型,B型14例,C型16例;均采用外固定架固定前环。INFIX组31例,其中男14例,女17例;年龄37~60岁,平均为(47.1±2.4)岁。骨盆骨折根据Tile分型:B型13例,C型18例;均采用皮下前环内置外架固定前环。比较两组患者的术后骨折复位质量、手术或术后并发症(包括医源性神经损伤、感染、螺钉松动、骨不愈合等)及疗效等。结果61例患者均获得随访,随访时间12~18个月,平均(14.2±2.3)个月。术后骨折复位质量根据Matta评分标准评定,APEF组优10例,良16例,可3例,差1例,优良率为86.7%;INFIX组优9例,良18例,可2例,差2例,优良率为87.1%;两组比较差异无统计学意义(P>0.05)。末次随访时根据Majeed骨盆功能评分系统评定疗效,APEF组优15例,良10例,可5例,优良率为83.3%;INFIX组优16例,良12例,可3例,优良率为90.3%;两组比较差异有统计学意义(P<0.05)。两组患者在术后3个月随访时骨折均全部愈合。APEF组3例(10%)患者股外侧皮神经损伤,5例(16.7%)出现螺钉松动,4例(13.3%)发生钉道感染;INFIX组4例(12.9%)出现股外侧皮神经损伤,1例(3.2%)出现皮肤感染,无螺钉松动发生。APEF组股外侧皮神经损伤发生率较INFIX组相比差异无统计学意义(P>0.05);APEF组患者螺钉松动、钉道感染率高于INFIX组,差异均有统计学意义(P<0.05)。结论APEF和INFIX均能提高骨盆的稳定性,但INFIX可获得较好的临床疗效,且并发症发生率较低,患者接受度高。     

腓骨内固定加管型石膏外固定治疗复杂Pilon骨折

目的探讨腓骨内固定加外固定治疗Pilon骨折的疗效。方法采用钢板螺钉内固定治疗腓骨骨折，然后用松质骨拉力螺钉或可吸收螺钉固定下胫腓关节，对压缩的胫骨取髂骨植骨，修复骨缺损，不做胫骨内固定手术，术后小腿管型石膏外固定。结果46例Pilon骨折，优36例，良5例，中3例，差2例。其中2例感染，皮肤伤口半年愈合，总优良率89．1％。结论有限内固定结合术后管型石膏外固定治疗Pilon骨折具有损伤小、愈合快、并发症少的优点。     

混合环形外固定支架治疗老年人胫骨下端开放性骨折

目的胫骨远端骨折为高能量骨折,其治疗极为棘手,尤其对于开放性胫骨远端的治疗尤为困难。我们采用混合环形外固定支架治疗老年人胫骨下端未移位开放性骨折,评价其临床治疗效果及并发症的发生。方法本组共11例,骨折类型为局限于胫骨下端干骺端骨折或累及踝关节但关节面平整者,均采用混合环形外固定支架进行治疗。如患者存在腓骨骨折,则采用常规手术方法1/3管型钢板固定腓骨,之后作环形混合外固定支架进行固定。术后抬高患肢,鼓励做脚趾的活动和踝关节的活动。术后1个月随访复查,术后2两个月进行负重训练。结果11例患者均得到随访,随访时间为12～24个月(平均14.6个月)。开始负重时间为术后6周～12个月(平均3.9个月)。住院时间为14～60d(平均20.5d)。骨折愈合时间为术后4～10个月(平均7.3个月)。所有患者均未出现深部感染,没有骨外露。2例患者出现原伤口感染,经过换药治疗后感染控制,自行愈合。所有患者的踝关节主、被动活动均未受限。拆除外支架时间为术后8～14个月(平均10.5个月)。拆除外支架后没有病例出现再次骨折。结论环形混合外固定支架是治疗胫骨下端未移位开放性骨折的一种较为理想和可靠的方法。     

外固定联合有限内固定治疗Tile C型骨盆骨折

目的探究外固定联合有限内固定治疗Tile C型骨盆骨折的临床疗效。方法对27例Tile C型骨盆骨折采用外固定支架联合有限内固定进行治疗,本组27例,25例获得随访,根据Tile分型,C1型17例,C2型8例。结果本组随访时间为6个月~2年,平均1.5年。骨盆骨折复位后根据Tornetta评分标准评价,优12例,良9例,可3例,差1例,总体优良率为84%;术后功能恢复情况采用MaJeed评分系统评价,优11例,良11例,中2例,差1例,总体优良率为88%。结论对于Tile C型骨盆骨折,采用外固定联合有限内固定双重固定不仅可以恢复骨盆环解剖序列的连续性和整体结构的稳定性,而且该方法具有实用、有效、手术创伤小、出血少、外固定支架调整拆卸方便等优点,值得在临床上推广使用。     

The Mechanics of External Fixation

External fixation has evolved from being used primarily as a last resort fixation method to becoming a main stream technique used to treat a myriad of bone and soft tissue pathologies. Techniques in limb reconstruction continue to advance largely as a result of the use of these external devices. A thorough understanding of the biomechanical principles of external fixation is useful for all orthopedic surgeons as most will have to occasionally mount a fixator throughout their career. In this review, various types of external fixators and their common clinical applications are described with a focus on unilateral and circular frames. The biomechanical principles that govern bony and fixator stability are reviewed as well as the recommended techniques for applying external fixators to maximize stability. Additionally, we have illustrated methods for managing patients while they are in the external frames to facilitate function and shorten treatment duration.