内锁钉断裂的生物力学原因分析

从1992年3月至1997年12月,对64例复杂粉碎性股骨骨折作了内锁钉固定。55例得到随访,从3个月到90个月(平均26个月)。共发生4例内锁钉断裂,断钉率为6.3％。经梅花钉固定加植骨3例,记忆合金环抱接骨器固定加植骨1例,骨折均愈合,并且功能3例优良,1例差。断钉发生在术后6月至14月,3例位于骨折远端第一枚横锁螺孔处,1例位于内锁钉中段。断钉原因有:开放穿钉,过度分离骨膜,过早负重及功能锻炼不合适等。另外,股骨远端第一枚横锁螺钉离骨折端太近,此处应力过于集中。预防断裂的方法有尽量闭合穿钉,选择较粗较长的内锁钉,横穿内锁螺钉应稍远离骨折端、避免过早负重及合适的功能锻炼等。     

股骨交锁髓内钉断钉原因探讨

目的 探讨交锁髓内钉断裂的原因。方法 对1998年至2001年72例股骨干骨折作交锁髓内钉固定患者进行随访。结果 61例获得随访，断钉5例，断钉发生在4－9个月，3例交锁钉钉体断裂，2例锁钉发生断裂。结论 开放穿钉，过度分度骨膜，过早负重及功能锻炼不适当等可致断钉。     

带锁髓内钉治疗股骨干骨折失败原因分析及其对策

目的探讨带锁髓内钉治疗股骨干骨折失败的原因及其预防措施。方法1999年4月至2002年9月采用带锁髓内钉治疗股骨干骨折患者213例,其中失败18例。回顾性分析这18例患者的临床资料,并对其进行分类。结果18例患者中,按失败原因可分为断钉3例,其中主钉断裂2例,主钉合并远端锁钉断裂1例;远端锁钉退出7例;近端锁钉退出3例;膝关节纤维性强直3例;迟发感染2例。手术技术、手术适应证选择、康复锻炼的规范性、髓内钉的强度及合适与否是导致失败的相关原因。结论应用带锁髓内钉治疗股骨干骨折应掌握好适应证,强调术前准备充分,术中操作规范,术后锻炼应循序渐进,避免过早负重,是减少或防止内固定失效的重要措施。     

新型锁钉设计的交锁髓内钉内固定治疗股骨干骨折疗效分析

目的 观察新型锁钉设计的交锁髓内钉内固定治疗股骨干骨折的临床疗效,总结新技术的优点。方法 纳入自2010-02—2020-02采用新型锁钉设计的交锁髓内钉内固定治疗的45例股骨干骨折,采用改良远端锁钉瞄准微调装置的髓内钉瞄准器钻孔并置入远端锁钉。先确定空心定位杆的偏移在髓内钉直径有效范围内,再固定好定位杆,通过螺母上下微调确定锁钉的钻孔位,用直径5.1 mm长钻头完成精确钻孔,如果钻孔时发生偏移,上下微调螺母后再矫正偏移即可完成钻孔过程,然后置入2枚远端锁钉。结果 本组共置入90枚远端锁钉,84枚一次锁钉成功,一次锁钉成功率为93.3%;其余6枚通过C型臂X线机定位徒手锁定。45例均获得随访,随访时间平均15(8～24)个月。所有患者均无切口感染、血管神经损伤,均未出现骨折畸形愈合、髓内钉断裂、锁钉松动等并发症。术后骨折均愈合,骨折愈合时间3～9个月,平均5.5个月。末次随访时膝关节功能HSS评分：优28例,良15例,可2例。结论 将新型锁钉设计的交锁髓内钉联合远端锁钉置入技术应用于治疗股骨干骨折可实现精准锁钉,解决了传统交锁髓内钉固定不稳定以及远端锁钉困难的问题,使骨折断端达到微动状...     

交锁髓内钉断裂原因探讨

目的：探讨交锁髓内钉断裂的原因。方法：从1998年3月～2001年10月，对130例长骨干骨折采用交锁髓内钉固定。结果：随访72例．平均随访13个月，共发生4例交锁髓内钉断裂。1例主钉断裂，3例横锁螺丝钉断裂。结论：作认为断钉原因为：髓内钉太细、长度不够、骨不连、手术设计不足、手术操作不当、过早负重等。     

瞄准器引导股骨交锁髓内钉远端锁钉的再认识

[目的]分析瞄准器引导下股骨交锁髓内钉远端锁钉困难的原因，以提高远端锁钉成功率。[方法]用配备远端瞄准器的股骨交锁髓内钉治疗股骨干骨折297例（301侧股骨），髓内钉301枚，国产钉216枚，进口钉85枚；粉碎性骨折108例，非粉碎性骨折189例；其中4例双侧股骨干骨折；均采取静力型固定，远近端各2枚锁钉。[结果]301枚股骨交锁髓内钉有288枚远端锁钉一次成功，有13枚初次锁钉未成功，一次锁钉成功率为95．7％。[结论]股骨交锁髓内钉远端锁钉困难的原因是多方面的，要提高远端锁钉一次成功率，必须重视包括术前准备在内的各个环节。     

交锁髓内钉治疗股骨干骨折失败原因分析

目的分析交锁髓内钉治疗股骨干骨折失败的相关因素并提出预防措施。方法对15例股骨干骨折交锁髓内钉内固定失败的病例进行相关因素分析和总结。结果15例病例中螺钉松动8例,螺钉断裂4例,主钉断裂2例,钉尾处再骨折1例,导致骨折畸形愈合8例,骨不连2例,膝关节功能受限5例。结论股骨干骨折交锁髓内钉内固定应该严格遵循生物力学原则,根据骨折部位选择适当的交锁髓内钉,在良好复位的同时尽量保护骨折处的血运。严格按照交锁髓内钉的操作程序进行,有骨缺损时应一期植骨。术后功能锻炼应根据骨折复位、固定情况循序渐进,避免术后过早负重。     

磁力导航下交锁髓内钉的远端螺钉锁定

目的 对磁力导航技术应用于交锁髓内钉远端锁钉的固定效果进行分析和评价。方法 30例股骨干骨折中，交锁髓内钉置入后，在磁力导航下完成远端交锁螺钉的固定。结果 30例均完成交锁髓内钉的远端锁钉，一次钻孔、锁钉成功率达100％。结论 磁力导航技术用于交锁髓内钉的远端锁钉有操作简便、定位准确、手术时间短、并发症少等优点。     

329例股骨干骨折带锁髓内钉内固定术并发症及处理对策

目的通过对5年所行329例股骨带锁髓内钉治疗股骨干骨折分析，探讨术后并发症及相应处理对策。方法对329例股骨干骨折患者行带锁髓内钉内固定术，其中单纯股骨干骨折294例、股骨干骨折合并转子下骨折35例。结果远端锁钉失败2l例(其中2枚远端锁钉均未锁上1例、1枚远端锁钉未锁上12例、锁钉松动退出5例、断1枚锁钉3例)，骨折端劈裂5例，骨折延迟愈合12例，骨不连3例．膝关节屈曲受限23例．断主钉1例。结论扩髓型带锁髓内钉治疗股骨干骨折，疗效肯定，但需注意术前选钉合理、术中操作规范、术后康复及时、科学。     

交锁髓内钉远端锁入可吸收螺钉治疗胫骨骨折

目的比较交锁髓内钉远端锁入可吸收螺钉与锁入金属锁钉静力型固定在治疗胫骨骨折中的临床效果。方法采用交锁髓内钉远端锁入可吸收螺钉固定治疗25例胫骨骨折患者（试验组）,检测骨折愈合及并发症情况,并与同期锁入金属锁钉静力型固定28例胫骨骨折（对照组）的随访结果进行比较。结果患者均获得随访,时间4~13个月。骨折愈合时间：试验组为13~16（14.28±0.94）周,对照组为14~18（15.89±1.13）周,差异有统计学意义（P〈0.01）。结论交锁髓内钉远端锁入可吸收螺钉比锁入金属锁钉静力型固定更有利于胫骨骨折愈合。     

Biomechanical analysis of the mechanism of interlocking nail failure

Summary From December 1986 to May 1989, 412 patients with 274 femoral and 144 tibial fractures were treated with Grosse-Kempf interlocking nails at our hospital. 324 cases (78.6%) were followed-up for at least 1 year (average 23 months). There were 13 breakages in the locking nails in femora and none in tibiae. The recorded incidence of breakage in the femur is therefore 4.7% (13/274). The mechanisms of locking nail failure are stress concentration around screw hole and nail slot, nicking of the nail during drilling of the screw holes, too close proximity of the screw hole to the fracture, and larger loading over the proximal femur. The incidence of failure is 4.9% in the upper third, 1.9% in the mid-third, and 8.2% in the distal third (P > 0.05, ² test). The site most at risk is the first screw hole of the distal third, especially if it is near the fracture site. Prevention of failure involves using a nail of larger diameter and sufficient length, improving the surgical drilling technique, and allowing only protected weight bearing. Management of nail breakage by insertion of a new implant and supplementary cancellous bone grafting can gain satisfactory results.     

Mechanical failure in intramedullary interlocking nails

PURPOSE: To study clinical and mechanical factors that predispose to failure of interlocking nails. METHODS: Between October 1996 and December 2002, 286 femoral fractures, 211 tibial fractures, and 47 humeral fractures were repaired using variously designed interlocking nails. Fracture pattern, level and site, nail size and type, weight bearing after nailing, and union status were reviewed after a mean follow-up of 22 months. RESULTS: Nail failure occurred in 27 fracture repairs (17 femoral, 9 tibial, and one humeral; 13 from our institution and 14 referred from elsewhere). In 55% of failed repairs, the fracture was distal. A high rate of tibial nail failure was noted. CONCLUSION: Distal fractures and stress concentration at the distal screws predispose to interlocking nail failure and can be prevented by protected weight bearing combined with the use of longer and larger nails. Routine supplementary cancellous bone grafting is unnecessary during renailing surgery when adequate reaming and a larger nail are used.     

股骨干骨折内固定失败的原因分析

目的：分析股骨干骨折内固定失败的原因并提出预防措施。方法：对36例股骨干骨折内固定失败的病例进行生物力学分析和总结。结果：36例中采用钢板内固定21例，梅花钉9例，“V”形针3例，国产带锁髓内钉3例。其中内固定物选择错误16例，骨折复位不良或有明显骨缺损18例，术后过早负重22例。所有病例经过再次手术内固定、植骨后全部愈合。结论：股骨干骨折内固定失败的主要原因是未遵循生物力学原则。根据骨折部位选择适当的内固定物、在良好复位的同时尽量保护骨折处的血运、有明显骨缺损时应一期植骨及术后功能锻炼应根据骨折复位、固定情况循序渐进，避免术后过早负重是预防股骨干骨折内固定失败的有效措施。     

Fatigue load of current tibial intramedullary nail designs: a simulated study

Comminuted tibial shaft fractures are traditionally treated with statically locked intramedullary nailing and protected weight bearing until fracture callous is evident. The purpose of this study was to demonstrate that a simulation of immediate full weight bearing following intramedullary nailing of these fractures does not result in implant failure.A comminuted fracture model was created using 2 pieces of polyvinyl chloride (PVC) pipe. Ten-millimeter-diameter tibial nails (Synthes, Paoli, Pennsylvania; Styker, Mahwah, New Jersey; Zimmer, Warsaw, Indiana; Smith & Nephew, Memphis, Tennessee) were inserted within the PVC pipe and secured proximally and distally with 2 or 3 locking bolts. The constructs were cycled in axial compression for 500,000 cycles or until implant failure. The tests were conducted using a modified staircase method (200 N per step), and the fatigue strength was identified for each of the tibial nail designs. When 2 interlocking bolts were placed proximally and distally, the fatigue strength was between 900 and 1100 N for the Stryker nail, 1100 and 1300 N for the Zimmer nail, 1200 and 1400 N for the Synthes nail, and 1400 and 1600 N for the Smith & Nephew nail. Adding a third interlocking bolt proximally and distally to the Smith & Nephew nail increased the fatigue strength by 13% to between 1700 and 1900 N. In all cases, implant failures occurred through the proximal or distal interlocking bolts.Biomechanical tests suggest that current tibial nail designs may permit immediate full weight bearing of comminuted tibial shaft fractures with minimal risk of implant failure. This may facilitate mobilization in the early postoperative period, especially in the multiply injured patient.     

小切口复位逆行交锁髓内钉治疗股骨远端骨折

目的探讨小切口复位逆行交锁髓内钉治疗股骨远端骨折的临床效果。方法2003年7月至2006年12月，对24例股骨远端骨折患者的手术治疗进行回顾性分析。按股骨远端骨折AO／ASIF分型，A型16例～型8例，治疗采用小切口复位逆行交锁髓内钉内固定。结果本组病例随访时间6～24个月（平均17．4个月），平均愈合时间为4．6个月，无术后感染，1例远端锁钉断裂，经制动后愈合。按Neer等膝关节评分标准进行评价，优15例，良6例，优良率87．5％。结论小切口复位逆行交锁髓内钉治疗股骨远端骨折，手术操作简单，固定可靠，对软组织破坏少，骨折愈合率明显提高，用于治疗股骨远端复杂骨折手术效果好。     

胫骨骨折的交锁髓内钉治疗

目的：观察交锁髓内钉在胫骨骨折中的治疗效果。方法：1997年2月－2000年2月对37例胫骨骨折采用交锁髓内钉治疗,男30例,女7例,年龄18－65岁,闭合性骨折28例,开放性骨折6例,陈旧性骨折2例,胫骨骨不连2例,开放性骨折采用非扩髓髓内钉,闭合性骨折采用扩髓髓内钉。结果：37例得到随访,骨折全部愈合,无锁钉及髓内钉松动、断裂,膝踝关节功能正常,迟发性感染1例。结论：交锁髓内钉在治疗胫骨骨折中具有创伤小、固定坚强、骨折愈合率高、能早期活动、感染率低等优点,是一种较好的内固定方法。     

胫骨带锁髓内钉治疗骨折与锁钉装置的改进

目的：探讨应用带锁髓内钉治疗胫腌骨骨折，在不需X线引导下进行手术的可行性和效果。方法：应用非扩髓带锁骨内钉治疗胫骨骨折46例。其中闭合性骨折25例，开放性骨折21例。改进带锁髓内钉远端瞄准器，增设辅助定位装置。结果：全部病例经随访6个月以上，除1例骨折术后10个月愈合外，45例骨折愈合时间平均4．8个月。患者膝、踝关节功能均恢复正常。改进后的带锁髓内钉远端瞄准器，一次钻孔交锁成功45例，无锁钉放置失败，术后无髓内钉或锁钉断裂。结论：非扩髓带锁髓内钉治疗胫腓骨骨折，手术不需X线引导，改进后的带锁髓内钉远端瞄准器，锁钉准确，简便实用。     

The effect of locked distal screws in retrograde nailing of osteoporotic distal femur fractures: a laboratory study using cadaver femurs

OBJECTIVES: To examine the effects of locked distal screws in retrograde nails used in unstable osteopenic distal femur fractures. DESIGN: Biomechanical testing of paired human cadaveric femurs. INTERVENTION: Seven matched pairs of embalmed, moderately osteopenic cadaver femurs were instrumented with 12-mm intramedullary nails in a statically locked, retrograde fashion. One femur of each pair had locked distal screws and the other femur had unlocked distal screws. A 2.5-cm gap of bone was cut nine centimeters from the distal condyles to simulate an unstable fracture. The locked distal screw nails were compared to unlocked distal screw nails for collapse of the fracture gap, medial-lateral and anterior-posterior translation of the nail within the fracture site, and fracture angulation. The femurs were axially loaded, cycled, and then loaded to failure. MAIN OUTCOME MEASURES: Motion at the fracture site with axial cyclic loading and site of failure when loaded to failure. RESULTS: After cycling, both locked distal screw and unlocked distal screw nails demonstrated several millimeters medial and anterior translation within the fracture site and approximately 1 mm collapse of the fracture gap. Although no statistically significant differences were found, the locked distal screw nails had less anterior and medial translation, angulation, and collapse of the fracture gap after cycling. Loads to failure were similar for both locked distal screw and unlocked distal screw nails. It was noted that proximal femur failure occurred at the level of the proximal screw hole in the nail at the subtrochanteric level in 7 (4 locked distal screws and 3 unlocked distal screw groups) of the 14 samples. Four other samples failed through the intertrochanteric region (2 locked distal screw and 2 unlocked distal screw groups) and the remainder within the distal fragment by fracture of the femur along the medial cortex. CONCLUSIONS: Although most differences in fixation stability were not significant, the locked distal screw nails exhibited less fracture collapse and anterior and medial translation of the nail at the fracture site than the unlocked distal screw nails. The degree of varus angulation after cyclic loading was also less for the locked distal screw nails. The length of the nail chosen should avoid having proximal locking screws distal to the lesser trochanter, thus averting proximal femur stress risers and fractures.