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。     

股骨交锁髓内钉远端锁钉困难的原因分析与二维置入法

目的分析股骨交锁髓内钉远端锁钉困难的原因并提出实用的处理方法。方法 47例股骨交锁髓内钉内固定术中均采用标准方式开路、扩髓、复位插钉,只安装瞄准装置的手柄及瞄准器纵轴定位杆,在纵轴定位杆远端2个定位孔采用二维置入法置入远端锁钉。结果一次性成功置入26例,占55.3%;再作调整后置入18例,占38.3%;置入失败3例,占6.4%。结论明确股骨交锁髓内钉远端锁钉困难的原理,正确掌握二维置入法,能准确、简便置入远端锁钉。     

电磁导航交锁髓内钉在胫骨干骨折中的应用

目的对电磁导航交锁髓内钉技术在胫骨干骨折中的应用的可行性与优势进行评价。方法笔者自2013-07—2015-11在电磁导航下闭合复位远端锁钉内固定治疗12例胫骨干骨折。结果本组均成功地完成了髓内钉闭合复位手术,本组12例远端24枚锁钉均在电磁导航下完成远端锁钉置入,远端锁定一次性成功率达100%,胫骨干髓内钉远端锁钉耗时8~14(11.03±1.78)min;比较在透视下徒手锁钉和使用普通瞄准器锁钉的用时明显减少。结论在电磁导航下行胫骨髓内钉远端锁钉置入效果满意,与普通交锁髓内钉远端锁钉置入相比有手术时间短、定位精确、对患者创伤小的优势。     

带远端锁钉定位装置的交锁髓内钉在股骨干骨折中的应用

目的评价带远端瞄准器的交锁髓内钉在股骨干骨折治疗中的应用特点。方法对采用带远端瞄准器的交锁髓内钉通过闭合复位穿钉技术治疗的26例股骨干骨折患者进行手术过程分析。结果远端锁钉放置顺利21例，放置困难经查找原因并改正后放置成功4例，失败1例。结论使用带远端锁钉定位装置的交锁髓内钉治疗股骨干骨折，可减少术者及患者暴露于X线下的次数及时间。只要操作中正确使用定位装置，减少髓内钉插入过程中产生的应力，减少钉的变形，即可顺利放置远端锁钉。     

股骨交锁髓内钉远端锁钉置入困难的原因分析及处理方法

目的 探讨股骨交锁髓内钉远端锁钉置入困难的原因和处理.方法 手术治疗各类型的股骨干骨折交锁髓内钉内固定手术共260例,分析手术中远端锁钉锁定的准确性,总结手术中的各种困难和所采取的处理措施.结果 一次性顺利置入2枚远端锁钉197例,多次调整和钻孔置入43例,只能置人1枚15例,锁钉误入髓内钉前方3例,误入髓内钉后方2例.结论 股骨交锁髓内钉远端锁钉置入困难的原因是多方面的,目前仍然没有统一的解决办法,手术者必须综合各种影响置人的因素,采取相应处理才能顺利地置人.     

“轴心法”引导远端锁钉治疗股骨干骨折29例分析

目的：探讨“轴心法”远端锁钉瞄准器术在股骨髓内钉治疗股骨干骨折的临床应用。方法应用“轴心法”远端锁钉瞄准器术完成T形杆入点的选择、髓内钉置人、远端锁钉的置入。结果29例股骨干骨折的应用结果令人满意，平均手术时间85分钟，平均X线采集图象2次，平均出血量180ml，手术中和手术后无并发症发生。结论肯定了轴心法远端锁钉瞄准器术在扩髓股骨交锁髓内钉手术中应用的可行性。手术中只需2次X线成像就能使术者的手术工具做到实时监测，减少了X线照射量、缩短了手术时间、提高了髓内钉置人的准确度、减小了手术创伤。     

Orthofix瞄准器在长管骨骨折内固定中的应用体会

目的：探讨Orthofix瞄准器在交锁髓内钉内固定中的正确使用方法。方法。通过对交锁髓内钉在长管理骨折内固定术中应用的系统回顾,总结交锁钉的有效方法。结果：17根交锁髓内钉均顺利按装,骨折全部愈合,除前2例锁钉不满意外其他均准确锁入,结论：Orthofix瞄准器的正确使用是保证交锁髓内钉治疗长管骨骨折的关键。     

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。     

远端锁钉盲置法在交锁髓内钉内固定术中的应用

目的探讨交锁髓内钉远端锁钉置入的新方法。方法2007年6月～2008年11月应用交锁髓内钉治疗下肢骨折72例,远端锁钉均采用盲置法置入,在远端瞄准器定位好长度后,于远端锁钉处直接切开显露,在骨质侧方正中用6mm粗钻头钻钻通近侧皮质,直视下可以看到髓内主钉远端锁孔,更换4.5mm钻头钻通对侧皮质,近端攻丝后直视下拧入锁钉。结果72例均得到随访,时间6个月～2年,平均14个月,均骨折愈合。其中延迟愈合14例,改动力性固定3个月后愈合,远、近端锁钉100%在位,无锁钉断裂和退出。结论远端锁钉盲置法在交锁髓内钉内固定术中的应用简单可靠,锁钉在位率100%,可减少医源性X线辐射,节省手术时间,使髓内钉技术更加微创化。     

带锁髓内钉治疗股骨干骨折与远端安锁定位装置

目的：总结带锁髓内钉治疗股骨干骨折的临床经验，改进远端锁钉瞄准器，方法：股骨干骨折32例中，新鲜骨折25例，陈旧性骨折7例，采用闭合穿钉治疗11例，半开放穿钉12例，开放穿钉9例，设制髓内钉定位孔及安锁定位装置。结果：本组病例随访6－23个月，平均12个月骨折均已愈合，按Klemm功能恢复分级评定；优21例，良9例，中2例，远端锁钉瞄准器改进后手术使用30例，无锁钉放置失败，一次交锁成功29例，结论：（1）应用带锁髓内钉固定，对闭合复位困难的股骨干新鲜骨折，采用半开放穿钉术，效果良好，（2）改进后的远端锁钉瞄准器无需X线引导，锁钉准确可靠。     

Treatment of femoral shaft fractures with a titanium intramedullary nail

Ninety-nine femoral shaft fractures were treated with locked intramedullary nails made from titanium alloy. One of the distal interlocking screws failed in six fractures (6%) and both screws failed in two fractures (2%). Delayed union was associated with all of the eight fractures that had locking screw failure. Young, heavier patients who had nails of small diameter had an increased risk of screw failure. Additional surgery was needed when both screws failed. The authors still use this nail, but currently prefer to ream the medullary canal more so that larger nails can be inserted. Decisions concerning weightbearing are made on an individual basis for each patient, and currently full weightbearing is delayed for young, active, and heavy patients. Two distal interlocking screws should be inserted for treatment of femoral shaft fracture when a Ti locked intramedullary nail is used.     

Stress analysis of the distal locking screws for femoral interlocking nailing.

In femoral locked nailing, the distal locking screws are vulnerable to mechanical failure. Biomechanical studies have shown that the stress on these screws is substantially affected by the fit of the nail in the medullary canal. In this study, a "closed form" mathematical model based on elastic beam-column theory was developed to investigate how the nail-cortical contact, which was simulated by a linear elastic foundation, affected the stress on the distal locking screws. Providing data for the model was a construct of a fractured femur with an intramedullary locked nail loaded by an eccentric vertical load. The stress on the locking screw was analyzed as a function of the distance from the fracture to the locking screw in the distal fragment under two situations: with and without nail-cortical contact in the distal fragment. With nail-cortical contact, the screw stress decreased as the length of nail-cortical contact and the distance between the distal locking screw and the fracture site increased, but this stress contrarily increased when the nail reached the femoral region at which the screw length increased. The screw stress was much higher without nail-cortical contact than with contact and continued to increase as the nail was inserted further. The mathematical model developed here can be a convenient means of rapid stress evaluation and parametric analysis for locked femoral nailing. It may be used to improve the design of interlocking nails and surgical technique.     

Interlocking intramedullary nails. An improved method of screw placement combining image intensification and laser light.

Insertion of distal interlocking screws in femoral nails can be technically demanding and may entail substantial exposure. A method of insertion of femoral interlocking screws that uses a laser guiding system in addition to the standard image intensifier was used in an attempt to improve the accuracy of distal screw placement and to limit radiation exposure. Using this technique, 97% of the distal femoral drill holes attempted were successfully made with the first pass of a drill. Little or no resistance to the drill was met from contacting the femoral nail. Average fluoroscopy time was 0.4 minute. Laser-assisted screw placement requires relatively inexpensive modifications of existing equipment and is easy to master. Compared with the more commonly used freehand method, laser-assisted screw placement appears to offer a reduction in the amount of time and radiation exposure required to insert distal interlocking femoral screws.     

低应力遮挡效应交锁髓内钉的研制与生物力学研究

目的 :研究新型股骨低应力遮挡交锁髓内钉治疗股骨干骨折的生物力学特性。方法 :将股骨干交锁髓内钉远端锁孔向近端分别扩大 1、 2、 3mm ,采用 4具成人男性尸体 8根股骨干标本制成横断骨折模型 ,分别打入 4种不同孔径髓内钉 ,进行骨折断端应力分析实验。结果 :远端锁孔直径 3mm的交锁髓内钉与实验中其它组相比较 ,应力遮挡率最小 ( 2 0 .6 0 %) (P <0 .0 5 ) ,在载荷—应变、载荷—位移、轴向强度及刚度上均占有明显优势 (P <0 .0 5 )。而 4种髓内钉在弯矩—应变、弯矩—桡度、扭矩—扭角关系中无明显差别。结论 :远端锁孔直径扩大 3mm的交锁髓内钉不但应力遮挡小 ,而且强度、刚度符合骨折内固定的生物力学要求 ,从而该实验为临床应用低应力遮挡交锁髓内钉提供了可靠理论依据。     

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.     

交锁髓内钉断裂的原因分析及对策

探讨交锁髓内钉断裂的原因,提出预防的对策。方法：从１９９２年至１９９７年,对６４例复杂粉碎性股骨骨折作了交锁髓内钉固定。结果：５５例随访,平均２６个月。共发生４例交锁钉断裂,断钉率为６．３％。断钉发生在术后６～１４月,３例位于骨折远端第１枚横锁螺孔处,１例位于交锁钉中段。结论：作者认为断钉原因有：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１枚横锁螺钉离骨折端太近,应力集中。预防断裂的方法有尽量闭合穿钉,选择较粗较长的交锁钉,交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。     

Surgical navigation based on fluoroscopy--clinical application for computer-assisted distal locking of intramedullary implants.

OBJECTIVE: Fluoroscopy is used to guide surgical instruments during orthopedic procedures. Radiation exposure and lack of spatial information are drawbacks of this method. Improvements are expected when fluoroscopy-based surgical navigation is used for intraoperative guidance, e.g., in computer-assisted distal locking of intramedullary implants. PATIENTS AND METHODS : The method was applied to 42 interlocking procedures during implantation of the short proximal femoral nail in 27 patients with pertrochanteric femoral fractures. Precision of interlocking, exposure time, operating time, and number of personnel required for computer-assisted distal locking were recorded. RESULTS: One misplaced interlocking screw was observed (2.3%), and contact between the drill bit and the nail during drilling was noticed in 8 cases (19%). The average exposure time was 16 seconds (range 4-42 seconds), and the procedure took an average of 43 min (range 20-70 min). The number of persons required for computer-assisted distal locking was reduced from three to one within the course of the study. CONCLUSIONS: Fluoroscopy-based surgical navigation provided precise intraoperative guidance for computer-assisted distal locking with minimal use of fluoroscopy. The complex system and related procedure times may be drawbacks in this application. Clinical studies are underway to define implants and surgical procedures where intraoperative guidance by fluoroscopy-based surgical navigation is beneficial for the patient and/or surgeon.     

Intramedullary osteosynthesis of complex proximal femoral fractures with the Targon PF nail

We evaluated the performance of the Targon PF nailing system in the treatment of complex proximal femoral fractures with a retrospective analysis of prospectively collected data for 94 patients with a complex proximal femoral fracture (subtrochanteric fracture or fracture with reversed fracture line pattern) treated with a Targon PF nail. There were no intra-operative femoral fractures. Late complications requiring reoperation were one femoral fracture and one fracture around the nail secondary to tumour. Seven nails had to be dynamised and a further six 'self-dynamised' at the site of the distal locking screw. One patient required revision of the distal locking. Only one other patient required secondary surgery for a wound haematoma. There were no cases of implant cut-out or non-union. The Targon PF nail represents a progressive development in the design of intramedullary nails for proximal femoral fractures and the results compare favourably with other intramedullary systems used to treat complex proximal femoral fractures.     

Failure of intertrochanteric nailing due to distal nail jamming

Nail impingement against the anterior femoral cortex during nail insertion, or anterior cortex penetration, has been described in the literature as a worrying complication. We describe a previously unreported surgical failure due to a compromised dynamic distal locking caused by distal jamming of the nail. An 80-year-old male suffered a closed right intertrochanteric femoral fracture. Due to the presence of a long medial fragment, a 240 mm long titanium trochanteric nail was chosen to stabilize the fracture. Dynamic distal locking was performed by placing the distal screw at the inferior rim of the elliptical locking hole to allow compression of the fracture site during weight-bearing. Six-month X-ray follow-up revealed a broken nail and nonunion of the fracture due to failed dynamization of the distal locking screw. The nail was removed and replaced by a total arthroplasty. Due to the femoral anterior bow of the shaft, anterior cortical impingement of the distal tip of a nail may result in the failure of the nail to slide within the diaphyseal canal when using a medium-length nail preventing compression of the fracture. Dynamic distal locking can be ineffective if the ability of the distal nail to slide within the diaphyseal canal is hindered. This type of scenario can represent an opportunity for anterior nail impingement. Distal jamming of the nail can thus compromise dynamic compression at the fracture site during loading, thus inducing nonunion of the fracture, and leading to breakage of the osteosynthesis device. For these reasons, caution is recommended when using medium-length trochanteric nails for unstable trochanteric fractures.