股骨远端、胫骨近端微创固定系统 (LISS-DF,LISS-PLT)

LISS(less invasive stabilization system)是一个带锁髓内钉技术的优势与生物学接骨板技术相结合形成的一个新的微创内固定系统[1].Rüedi等则将LISS作为一种内固定器原则的概念,用外固定支架来理解,只是这种固定杆非常贴近骨面,接骨板与骨面无接触和压迫,这个特点可以防止任何对骨血运的破坏.使用长接骨板代替长的管状固定杆;使用能紧紧地锁扣于接骨板的头部带螺纹的强力自攻自钻螺丝钉取代外固定支架中广泛使用的Schanz钉和突起的紧固夹钳[2].     

锁定加压接骨板在骨折治疗中的应用

锁定加压接骨板(LCP)是国际内固定研究会基于生物学内固定理念研发的新型内固定系统,其特征是动力加压孔和圆雏形锁定螺纹孔相结合.既能作为单纯AO加压接骨板,用普通螺丝钉对简单骨折行加压固定,也能作为一种内固定支架.运用锁定螺钉对粉碎性骨折行桥接固定.还能对同时有关节内、外骨折或长骨干简单骨折伴发邻近部位粉碎性骨折患者同时进行加压和桥接固定.LCP的临床应用广泛,尤适于治疗骨折部位邻近关节或伴发严重骨质疏松的患者.LCP具有独特的力学特性,临床上如不遵循LCP手术操作原则而盲目使用,仍会导致手术失败.该文就LCP的结构与力学特点、临床应用效果及问题作一综述.     

MIPPO技术LCP钢板内固定治疗胫骨干多节段骨折21例分析

胫骨多段骨折通常由高能量暴力引起．骨折大多不稳定且常伴有严重的软组织损伤．是临床治疗较为棘手的骨折之一。近年来在动力加压接骨板（DCP）和有限接触动力加压接骨板（LC—DCP）的基础上．结合AO的点接触接骨板（PC—Fix）和微创固定系统（LISS）研发出来的一种全新锁定加压接骨板（LCP）为解决这一问题提供了一种崭新而有效的方法。     

AO/ASIF锁定加压接骨板在上肢近关节粉碎性骨折中的应用

锁定加压钢板（LCP）是AO／ASIF组织在限制性接触加压接骨板（LCDCP）、接触内固定系统和微创内固定系统的基础上研制出的一种新型接骨扳。笔者选取2002年2月～2004年10月,采用瑞士Mathys公司生产的LCP浩疗上肢近关节粉碎性骨折38例,均获得良好的效果。     

解剖型锁定加压接骨板微创治疗Pilon骨折

目的介绍解剖型锁定加压接骨板微创治疗Pilon骨折的方法,并观察其效果。方法采用微创手术治疗Pilon骨折14例,均采用解剖型锁定加压接骨板经皮内固定。结果随访3~12个月,平均8个月。全部创口愈合良好,无骨折延迟愈合和不愈合。按Mazur踝关节症状和功能评分系统进行疗效评定,优11例,良2例,可1例。结论临床疗效与治疗方法密切相关,解剖型锁定加压接骨板微创治疗Pilon骨折可以获得确实可靠的效果。     

微创内固定系统与锁定加压接骨板治疗胫骨近端骨折的对比研究

目的对比研究生物学固定技术（biological osteosynthesis,BO）微创内固定系统（less invasive stabilization systems,LISS）与锁定加压接骨板治疗胫骨近端骨折患者的临床疗效。方法回顾分析2005年5月至2009年3月收治的胫骨近端骨折患者32例,男23例,女9例;年龄28～57岁,平均46岁;左侧17例,右侧15例;交通伤18例,高处坠落伤6例,跌伤8例;闭合性骨折27例,开放性骨折5例;新鲜骨折31例,陈旧骨折1例。骨折按AO/OTA分类：A型关节外骨折24例,C型关节内骨折8例。随机分为2组,各16例,分别进行LISS治疗和锁定加压接骨板治疗,术前X线片示均为胫骨平台粉碎性骨折,胫骨近端骨折。将术中对骨缺损较大患者进行一期植骨,术后观察对伤口愈合情况、术后X线检查结果及关节功能恢复情况。结果全部获得随访,随访时间为3～23个月,平均13个月。术后12个月行X线检查示骨折对位对线佳,骨折均愈合,愈合时间为5～8个月,平均6.4个月。按照Kolmert和Wulff的评价标准：锁定加压接骨板治疗组,优10例,良4例,可2例,优良率为86.5%;LISS治疗组,优12例、良3例、可1例,优良率为93.8%。结论 LISS具有微创、安全、简便、快速的特点,治疗胫骨近端骨折的切口愈合时间、长度、骨折愈合时间、膝关节功能恢复等方面均优于锁定加压接骨板。     

锁定加压接骨板应用原则及注意事项

锁定加压接骨板技术符合生物学内固定(BO)原则,尤其是对复杂骨折具有不可比拟的优势和广阔的应用前景.目前临床上对正确应用锁定加压接骨板的原则及应用螺钉的注意事项,尚未统一.该文就锁定加压接骨板的设计原理、应用适应证及临床应用原则作一综述.     

锁定加压接骨板治疗骨折术后钢板螺钉断裂原因分析

目的 分析锁定加压接骨板固定骨折后钢板螺钉出现断裂的原因。方法 对收治的8例应用锁定钢板后出现钢板螺钉断裂的病例进行回顾性分析。结果 1例因钢板过短,5例因螺钉密度过大,1例因未对骨折端进行加压,5例未进行植骨,4例为开放性伤口,局部血运破坏严重,1例术后感染,2例因操作技术不当。 结论 锁定钢板的应用,除了应遵循AO内固定原则外,还需遵循其本身的特点及使用要求,以免内固定物断裂。     

微创锁定接骨板技术治疗股骨转子间骨折的临床研究

目的评价通过微创接骨板技术以锁定加压接骨板内固定治疗股骨转子间骨折的疗效。方法从2007年10月至2009年10月,通过微创接骨板技术以锁定加压接骨板内固定治疗35例股骨转子间骨折。男性22例,女性13例,年龄17～84岁,平均51岁。按AO/OTA分类,A1 9例,A2 19例,A3 7例。无开放性骨折。以临床功能和X线检查评定治疗效果。结果 35例均获随访,平均随访时间13个月（4～28个月）。35例骨折全部愈合,平均愈合时间为13周（9～16周）,没有发生内固定失败以及骨不愈合者。发生浅表感染1例。髋关节功能评价（Harris）优良31例,优良率88.5%。结论微创锁定接骨板技术操作简单,创伤小,效果好,是治疗股骨转子间骨折的一种有效方法。     

微创经皮接骨板技术治疗胫骨骨折21例体会

目的观察AO锁定加压钢板结合微创经皮接骨板技术治疗胫骨中下段骨折的临床效果。方法选择AO锁定加压钢板使用微创经皮接骨板技术,对32例胫骨中下段骨折进行手术固定。术后平均随访7．5个月。结果29例骨折复位良好、顺利愈合且功能恢复良好,3例出现延迟愈合。结论运用锁定加压钢板结合微创经皮接骨板技术治疗胫骨中下段骨折具有较高的临床应用价值。     

From the classical AO compression plate to the new internal fixator principle

TheclassicalAOprinciplesarebasedupontheanatomicalreconstructionononesideandinterfragmentarycompressionontheother.Providingabsolutestabilitytoafracturehasbeenthegoal,whichinturnallowedpainfreemovementoftheinjuredlimbandthepatientasawhole.Whilethese3AOprincipleswereusuallywellrespected,thefourthprinciple,whichhadbeenestablishedfromtheverybeginningandwhichaddressestheimportanceofthebiologyandthecareforthesofttissuesandboneaswell,hasoftenbeenneglectedormisunderstood.Woundbreakdownandinfectionasw…     

General principles for the clinical use of the LCP

The basic principles of an internal fixation procedure using a conventional plate and screw system (compression method) are direct, anatomical reduction and stable internal fixation of the fracture. Wide exposure of the bone is usually necessary to gain access to and provide good visibility of the fracture zone to allow reduction and plate fixation to be performed. This procedure requires pre-contouring of the plate to match the anatomy of the bone. The screws are tightened to fix the plate onto the bone, which then compresses the plate onto the bone. The actual stability results from the friction between the plate and the bone. Anatomical reduction of the fracture was the goal of conventional plating technique, but over time a technique for bridging plate osteosynthesis has been developed for multifragmentary shaft fractures that, thanks to a reduction of vascular damage to the bone, permits healing with callus formation, as seen after locked nailing. Since the damage to the soft tissues and the blood supply is less extensive, more rapid fracture healing can be achieved. The newly developed, so-called locked internal fixators (e.g.PC-Fix and Less Invasive Stabilization System (LISS)), consist of plate and screw systems where the screws are locked in the plate. This locking minimizes the compressive forces exerted by the plate on the bone. This method of screw-plate fixation means that the plate does not need to touch the bone at all, which is of particular advantage in so-called Minimal Invasive Percutaneous Osteosynthesis (MIPO). Precise anatomical contouring of a plate is no longer necessary thanks to these new screws and because the plate does not need to be pressed on to the bone to achieve stability. This prevents primary dislocation of the fracture caused by inexact contouring of a plate. The LISS plates are precontoured to match the average anatomical form of the relevant site and, therefore, do not have to be further adapted intraoperatively. The development of the locked internal fixator method has been based on scientific insights into bone biology especially with reference to its blood supply. The basic locked internal fixation technique aims at flexible elastic fixation to initiate spontaneous healing, including its induction of callus formation. This technology supports what is currently known as MIPO. The development of the Locking Compression Plate (LCP) has only been possible based on the experience gained with the PC-Fix and LISS. With reference to the mechanical, biomechanical and clinical results, the new AO LCP with combination holes can be used, depending on the fracture situation, as a compression plate, a locked internal fixator, or as an internal fixation system combining both techniques. The LCP with combination holes can also be used, depending on the fracture situation, in either a conventional technique (compression principle), bridging technique (internal fixator principle), or a combination technique (compression and bridging principles). A combination of both screw types offers the possibility to achieve a synergy of both internal fixation, methods. If the LCP is applied as a compression plate, the operative technique is much the same as conventional technique, in which existing instruments and screws can be used. The internal fixator method can be applied through an open but less invasive or an MIPO approach. An indirect closed reduction is necessary when using the LCP in the internal fixator method bridging the fracture zone. A combination of both plating techniques is possible and valuable, depending on the indication. It is important to command a knowledge of both techniques and their different features.     

Mechanical analysis of the bone to plate interface of the LC-DCP and of the PC-FIX on human femora

The scope of this analysis was to evaluate the mechanical behaviour of newly developed plates at the junction between plate and bone (friction between plate and bone) for the limited contact dynamic compression plate (LC-DCP) and the point contact fixator (PC-Fix) under simulated physiological load and using the tension band principle on the human femur. The intact human cadaveric femora were plated on the lateral aspect according to the tension band principle (AO) and subjected to a load which simulated careful physiological load in single stance. Five strain gauges were glued around the bones, parallel to the bone axis, at five levels, whereby three of them had to be covered by a bone plate and the two others were just outside the plate location. The cross-sectional geometry had been obtained at these levels using computed tomography. One side was plated using the conventional compression plate LC-DCP and the contralateral side using the internal fixator PC-Fix. The LC-DCP was affixed using screws tightened at different torque values and the PC-Fix at a standard torque value. Motion (slippage) between the plate and the bone was indicated by a hysteresis of the strain reading during loading and unloading. Slippage was more important for the LC-DCP than for the PC-Fix, particularly at the proximal end of the plate and when the screws were insufficiently tightened on the LC-DCP. As expected, better stability was obtained with the PC-Fix.     

Guidelines for the clinical application of the LCP

The Locking Compression Plate (LCP), in combination with the LISS and the PHILOS, is part of a new plate generation requiring an adapted surgical technique and new thinking about commonly used concepts of internal fixation using plates. The following guidelines are needed to avoid failures and possible complications in the hands of surgeons not yet confident with the new implant philosophy. The importance of the reduction technique and minimal-invasive plate insertion and fixation is addressed to keep bone viability undisturbed. Understanding of mechanical background for choosing the proper implant length and the type and number of screws is essential to obtain a sound fixation with a high plate span ratio and a low plate screw density. A high plate span ration decreases the load onto the plate. A high working length of the plate in turn reduces the screw loading, thus fewer screws need to be inserted and the plate screw density can be kept low. Knowledge of the working length of the screw is helpful for the proper choice of monocortical or bicortical screws. Selection is done according to the quality of the bone structure and is important to avoid problems at the screw thread bone interface with potential pullout of screws and secondary displacement. Conclusive rules are given at the end of this chapter.     

Revolution in plate osteosynthesis: new internal fixator systems

 Conventional plating has been performed since the nineteenth century, and since then Lambotte, Danis, and others have developed new plate designs to restore fractured bones. At the early stage of plating, mechanical aspects were the focus, and the biology of the bone was sometimes neglected. During the 1980s the AO/ASIF group started to work on new plate designs to minimize the disadvantages of plating with respect to cortical perfusion. To overcome the negative effect of compression forces on the periosteum, a new generation of plates, or internal fixators, were created. The key to these internal fixators is the locking mechanism of the screw in the implant, which provides angular stability. This technical detail ensures that compression forces on the bone surface are not necessary to gain stability of the bone–implant construct, which improves fracture healing and provides an excellent holding force even in osteoporotic bone. The locking mechanism also makes the technique of percutaneous plating easier because, in contrast to conventional plates, the fragments are not pulled toward the implant by the locking screws. The new internal fixator systems [LISS (less invasive stabilization system) and LCP (locking compression plates)] offer new approaches to trauma surgery, especially for metaphyseal fractures. Received: July 22, 2002 Offprint requests to: M. Schütz Presented at the 75th Annual Meeting of the Japanese Orthopaedic Association, Okayama, Japan, May 18, 2002     

Less invasive stabilization system (LISS) in the treatment of distal femoral fractures

The treatment of distal femoral fractures has been associated with a high rate of complications for a long time. Although implants and surgical techniques have improved, plate osteosynthesis and intramedullary nailing have been accompanied by a high occurrence of infection, non-union and malalignment. The treatment of soft tissue envelopes using "biological" osteosynthesis and minimally invasive approaches has resulted in a decrease in complication rates and ultimately led to the concept of the less invasive stabilization system (LISS). This is an extramedullary-applied, internal fixator shaped according to the implantation site anatomy, with minimal invasiveness. The purpose of this study was to present this new surgical technique and draw attention to its advantages and importance. Although this is not a scientific paper, we hope to provide enough evidence of the LISS usefulness. The main LISS components include multiple-fixed angle screws and an insertion handle for submuscular sliding of a fixator and placement of percutaneous, self-drilling, unicortical screws for fixation of the diaphyseal fracture fragments. The LISS has been designed to preserve periosteal perfusion and to facilitate a minimally invasive application. Since the first implantation of the LISS, only a few studies have been published on its use in treatment of distal femoral fractures. The rate of infection has been low, ranging from 0 to 4%. The rate of delayed union has been between 2.4 and 6.1%, but delayed unions do not necessarily lead to secondary bone grafting or repeat osteosynthesis as the LISS has a high and lasting stability. When the LISS is used, bone grafting is rarely necessary (0 to 1.6% in primary and 0 to 5% in secondary grafting). Also implant failure differs from the failure of plate osteosynthesis because, with the use of LISS, no screw loosening or secondary malalignment occurs. Implant failures (up to 7.4%) were recorded particularly at the time of LISS introduction in surgical practice and were attributed to the technique of implantation rather than to the implant itself. Good treatment outcomes have been reported. The average knee flexion has been 103 degrees and 107 degrees. In 72.5% of the patients, flexion has been more than 90 degrees and an extension lag of > or = 10 degrees has been found in only 7.5% of all cases. The average Neer score has ranged from 73.9 to 77.2 points. In conclusion, the LISS is a useful implant for treatment of distal femoral fractures, especially when bone quality is poor. Infection, delayed union and non-union rates are low, as shown by yet unpublished data from our clinic. Primary bone grafting, which is rarely necessary with this system, is carried out only when there is a great bone loss. Implant failure, such as screw loosening or secondary malalignment, is not seen.     

Biomechanical evaluation of the less invasive stabilization system and the 95-degree angled blade plate for the internal fixation of distal femur Fractures in human cadaveric bones with high bone mineral density

BACKGROUND: The less invasive stabilization system (LISS) is an internal fixator that utilizes unicortical locked screws for fixation of distal femur fractures. A question is whether locked unicortical screw fixation is sufficient, when compared with a standard implant such as a blade plate. METHODS: Eight matched pairs of fresh-frozen cadaveric femora were instrumented with either the LISS or a 95-degree blade plate. A 4-cm supracondylar gap fracture model was created and all bone-implant constructs were tested to failure in axial loading. RESULTS: All constructs failed by plastic deformation of the implant. There was no significant difference between the LISS and the blade plate constructs with respect to load to failure. CONCLUSIONS: Despite unicortical fixation axial loading to failure of the LISS did not result in implant/screw pull-out neither proximally nor distally. However, there does not appear to be a biomechanical advantage of using the LISS as opposed to a blade plate in bones with high bone mineral density.     

Biomechanical testing of the LCP--how can stability in locked internal fixators be controlled?

New plating techniques, such as non-contact plates, have been introduced in acknowledgment of the importance of biological factors in internal fixation. Knowledge of the fixation stability provided by these new plates is very limited and clarification is still necessary to determine how the mechanical stability, e.g. fracture motion, and the risk of implant failure can best be controlled. The results of a study based on in vitro experiments with composite bone cylinders and finite element analysis using the Locking Compression Plate (LCP) for diaphyseal fractures are presented and recommendations for clinical practice are given. Several factors were shown to influence stability both in compression and torsion. Axial stiffness and torsional rigidity was mainly influenced by the working length, e.g. the distance of the first screw to the fracture site. By omitting one screw hole on either side of the fracture, the construct became almost twice as flexible in both compression and torsion. The number of screws also significantly affected the stability, however, more than three screws per fragment did little to increase axial stiffness; nor did four screws increase torsional rigidity. The position of the third screw in the fragment significantly affected axial stiffness, but not torsional rigidity. The closer an additional screw is positioned towards the fracture gap, the stiffer the construct becomes under compression. The rigidity under torsional load was determined by the number of screws only. Another factor affecting construct stability was the distance of the plate to the bone. Increasing this distance resulted in decreased construct stability. Finally, a shorter plate with an equal number of screws caused a reduction in axial stiffness but not in torsional rigidity. Static compression tests showed that increasing the working length, e.g. omitting the screws immediately adjacent to the fracture on both sides, significantly diminished the load causing plastic deformation of the plate. If bone contact was not present at the fracture site due to comminution, a greater working length also led to earlier failure in dynamic loading tests. For simple fractures with a small fracture gap and bone contact under dynamic load, the number of cycles until failure was greater than one million for all tested constructs. Plate failures invariably occurred through the DCP hole where the highest von Mises stresses were found in the finite element analysis (FEA). This stress was reduced in constructions with bone contact by increasing the bridging length. On the other hand, additional screws increased the implant stress since higher loads were needed to achieve bone contact. Based on the present results, the following clinical recommendations can be made for the locked internal fixator in bridging technique as part of a minimally invasive percutaneous osteosynthesis (MIPO): for fractures of the lower extremity, two or three screws on either side of the fracture should be sufficient. For fractures of the humerus or forearm, three to four screws on either side should be used as rotational forces predominate in these bones. In simple fractures with a small interfragmentary gap, one or two holes should be omitted on each side of the fracture to initiate spontaneous fracture healing, including the generation of callus formations. In fractures with a large fracture gap such as comminuted fractures, we advise placement of the innermost screws as close as practicable to the fracture. Furthermore, the distance between the plate and the bone ought to be kept small and long plates should be used to provide sufficient axial stiffness.     

Less Invasive Stabilization System for treatment of distal femur fractures

The low profile of Less Invasive Stabilization System (LISS) plates allows them to be inserted between muscle and diaphysis with less bone exposure than that obtained with conventional plating techniques. In the unique LISS mechanism, unicortical screws thread into both plate and bone and allow the system to act as an internal fixator, with compressive pressure no longer bearing down on the periosteum. Results are minimal soft-tissue, periosteal, cortical, and vascular damage and no compromise in stability. This lesser degree of tissue disruption is hypothesized to accelerate bone healing, make bone grafting unnecessary, decrease infection rates, and prevent further injury by lessening overall surgical trauma. In a prospective, nonrandomized study conducted at a level I trauma center, we sought to determine the benefits of LISS plating in the treatment of distal femur fractures. Between January 1, 1998, and June 3, 2001, we treated 25 multiply injured adult patients admitted through the trauma department with 26 unstable distal femur fractures. Treatment involved minimally invasive plate osteosynthesis using LISS plating. Main outcome measures were time to union, postoperative complications, and functional impairment as measured with the SF-36v2 Health Survey. Results included no nonunions, no infections, no required bone grafting, and excellent range of motion and alignment.     

Submuscular plating of the distalfemur

A variety of implants are available for the treatment of distal femur fractures. However, continued problems includeinfection, nonunion, need for bone grafting, malunions, joint stiffness, and loss of fixation. “Biological plating” emphasizes maintenance of the soft tissue environment around the fracture. The concept of “biological plating” in supracondylar femur fractures has been very advantageous. The Less Invasive Stabilization System (LISS) for fractures of the distal femur combines these biological advantages of submuscular fixation with the biomechanical advantage of fixed angled, locked screws for fixation of the distal femoral block. The LISS may be particular helpful in the setting of complex articular pathology, a short distal segment, and osteoporotic bone. LISS methodology relies on traditional internal fixation of the articular surface, closed reduction of metaphyseal/diaphyseal component of the fracture, and placement of a submuscular LISS fixator. Percutaneous locking screws are then placed for proximal fixation. In this review, the evolution of submuscular fixation of supracondylar femur fractures and the technique are described.