principios lcp

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Injury, Int. J. Care Injured 34 (2003) S-B31S-B42

The basic principles of an internal fixation procedureusing a conventional plate and screw system (compres-sion methode) are direct, anatomical reduction and sta-

ble internal fixation of the fracture. Wide exposure ofthe bone is usually necessary to gain access to and pro-vide good visibility of the fracture zone to allow reduc-tion and plate fixation to be performed. This procedurerequires pre-contouring of the plate to match theanatomy of the bone. The screws are tightened to fix the

plate onto the bone, which then compresses the plateonto the bone. The actual stability results from the fric-tion between the plate and the bone.

Anatomical reduction of the fracture was the goal ofconventional platingtechnique, but over time a tech-nique for bridging plate osteosynthesis has been devel-oped for multifragmentary shaft fractures that, thanksto a reduction of vascular damage to the bone, permitshealing with callus formation, as seen after locked nail-ing. Since the damage to the soft tissues and the bloodsupply is less extensive, more rapid fracture healing can

be achieved.The newly developed, so-called locked internal fixa-

tors (e.g. PC-Fix and Less Invasive Stabilization System(LISS)), consist of plate and screw systems where thescrews are locked in the plate. This locking minimizesthe compressive forces exerted by the plate on the bone.This method of screw-plate fixation means that the platedoes not need to touch the bone at all, which is of par-ticular advantage in so-called Minimal Invasive Percu-taneous Osteosynthesis (MIPO). Precise anatomicalcontouring of a plate is no longer necessary thanks to

these new screws and because the plate does not needto be pressed onto the bone to achieve stability. This pre-vents primary dislocation of the fracture caused by inex-act contouring of a plate. The LISS plates are precon-toured to match the average anatomical form of the rel-evant site and, therefore, do not have to be furtheradapted intraoperatively.

The development of the locked internal fixator meth-ode has been based on scientific insights into bone biol-

ogy especially with reference to its blood supply. Thebasic locked internal fixation technique aims at flexibleelastic fixation to initiate spontaneous healing, includ-ing its induction of callus formation. This technologysupports what is currently known as MIPO.

The development of the Locking Compression Plate(LCP) has only been possible based on the experiencegained with the PC-Fix and LISS. With reference to themechanical, biomechanical and clinical results, the newAO LCP with combination holes can be used, depend-ing on the fracture situation, as a compression plate, alocked internal fixator, or as an internal fixation systemcombining both techniques.

The LCP with combination holes can also be used,depending on the fracture situation, in either a conven-tional technique (compression principle), bridging tech-nique (internal fixator principle), or a combination tech-nique (compression and bridging principles). A combi-nation of both screw types offers the possibility toachieve a synergy of both internal fixation methodes. Ifthe LCP is applied as a compression plate, the operativetechnique is much the same as conventional technique,in which existing instruments and screws can be used.The internal fixator method can be applied through anopen but less invasiv or an MIPO approach. An indirect

1 Abstracts in German, French, Italian, Spanish, Japanese andRussian are printed at the end of this supplement.

General principles for the clinical use of the LCP

Michael Wagner

Klinik fr Trauma and Sportmedizin, Wilhelminenspital Wien1171 Wien, Austria

Summary1

00201383/$ see front matter # 2003 Published by Elsevier Ltd.

doi:10.1016/j.injury.2003.09.023


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closed reduction is necessary when using the LCP in theinternal fixator methode bridging the fracture zone.

A combination of both plating techniques is possibleand valuable, depending on the indication. It is impor-tant to command a knowledge of both techniques andtheir different features.

Keywords: Locking Compression Plate (LCP), com-bination hole, Dynamic Compression Unit (DCU), con-ventional plating technique (compression principle),

bridging plate technique (internal fixator principle),Minimal Invasive Percutaneous Osteosynthesis (MIPO)Injury 2003, Vol. 34, Suppl. 2

Introduction

The AO has developed techniques and defined thebasic principles of internal fixation. There are currently

various methods and techniques for plate osteosynthe-sis:

Conventional plating technique

1) Open reduction and internal fixation (ORIF): Direct,open, precise reduction and stable internal fixation (con-ventional technique, compression methode principlegreater absolute stability) with plates and screws hasestablished itself as a standard and successful techniquefor treating bone fractures. Standard plates producecompression between the implant and the bone and onlywork, if they are pressed to the bone.

However, some problems in internal fixation withplates (DCP) and screws remain unsolved. Two of whichwere implant related and therefore technical issues: pri-mary and secondary loss of reduction leads to misalign-ment and instability, and the third leads to compressionof the periosteum, which causes a disturbance of the bone

blood supply. The biological shortcomings of direct openreduction and conventional compression plating aredamage to the blood supply to the bone, which can leadto biological complications. Compression plating needsgood bone quality and precise, anatomical reduction. In

multifragmentary shaft fractures, precise anatomicalreduction is often not possible without a great risk of aniatrogenic soft tissue trauma. [4, 9]

The total injury of the bone and the surrounding soft-tissue is caused by trauma and by the operative injury(iatrogenic injury). The operative injury = damagecaused by reduction + approach + fixation of fracture.Additional surgical damage can be reduced by adjustingthe surgical technique e.g., a change in soft-tissue han-dling, reduction, and fixation techniques (insertion andchoice of implant). New methods that bear a minimal riskfor treating problematic fractures were developed toaccelerate bone regeneration and bone healing. [6]

2) Biological bridge plating: Indirect, closed or openbut less invasive (no touch technique) reduction andbiological bridge plating (LC DCP, DCS, DHS etc.),greater relative stability. [2, 3].

3) MIPO-technique: Indirect, closed reduction andsub muscular / subcutaneous sliding techniques. Bridg-

ing the fracturezone, internal fixator method (withangular stable implants/locked screws PC Fix, LISS),greater relative stability. [6, 7, 8, 10, 11]

Indirect, closed reduction and bridging of the fracturezone with locked internal fixators (LIF) were often seenas a solution to the problems of ORIF.

Plate and screw systems, where the screw can belocked in the plate, form one stable system and the sta-

bility of the fracture depends on the stiffness of the con-struct. No compression of the plate on the bone isrequired to suppress the risk of primary loss of reduc-tion and preserve the bone blood supply. Locking thescrew into the plate to ensure angular as well as axial

stability eliminates the possibility for the screw to tog-gle, slide or be dislodged and thus greatly reduces therisk of postoperative secondary loss of reduction.

Based on the experiences gained with the PC-Fix sys-tem, the LISS DF and LISS PLT systems were developedand have shown very promising clinical results.

Preconditions for internal fixation by MIPO: Indirect closed reduction without exposure of the

fracture. Small incisions for the insertion of the implants. Elastic bridging of the fracture zone with a locked

internal fixator (e.g., LISS, LCP). Implants with minimal bone contact. Slightly ele-

vated plate from the bone surface to eliminate anymismatch of the precontured plate to the anatomy ofthe bone.

Self-drilling and self-tapping locking head screws formono- or bicortical insertion.

Only for LISS: Ageometrical correlation between aim-ing handle and plate for closed application.

Relative stability (elastic fixation) increases callus for-mation.

Note: The same technique may be used by the less expe-rienced with an open, but less invasive approach. [6]

Some years ago, we expressed the desire to have a 1-plate system with the possibility for the surgeon tochoose pre- or intraoperatively, whether or not to use itwith conventional screws, locked screws or with a com-

bination of both screws. This desire led to the develop-ment of the combination hole of the LCP. [1, 12, 13]

Different methods, different techniques, and dif-ferent biomechanical principles to use the LCP

The LCP with combination holes allows applications asa conventional compression plate as well as an internal

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fixator with locking head screws. Under certain cir-cumstances, the two principles may be incompatible.Therefore, it is advisable to use only one of the two tech-niques in one fracture zone, either conventional or asinternal fixator.

The LCP with combination holes can be used for the fol-lowing fracture situations: Conventional technique (compression methode prin-

ciple of absolute stability > primary fracture healing). MIPO technique (internal fixator methode principle

of relative stability > secondary fracture healing). Combination of both (compression and bridging with

LIF).

Different indications

Choosing to use a LCP depends on a number of factors:

1) Clinical stand point:

Fracture location and configuration. Soft-tissue conditions. Condition of the patient (polytrauma, ISS).

2) Other factors:

Presence of other implants. Im-nail? Borderline indication: metaphyseal zone,

size of the medullary canal, etc.? Personal experience and preference.

Availability of implants (i.e., LCP), instruments, andintraoperative imaging.

There are different indications to use the LCP for dif-ferent techniques and biomechanical principles (Table 1):

1) LCP in a conventional plating technique (com-pression method, principle of absolute stability):

Simple fractures in the diaphysis and metaphysis (ifprecise, anatomical reduction is necessary for thefunctional out come/Simple transverse or obliquefractures with low soft tissue compromise)

Articular fractures (buttress plate). Delayed or non-union. Closed-wedge osteotomies.

2) LCP in a MIPO-technique bridging the fracturezone (internal fixator method, principle of relativestability):

Multifragmentary fractures in the diaphysis andmetaphysis.

Simple fractures in the diaphysis and metaphysis (ifa non-precise reduction is enough for the functionaloutcome. The strictly/following of the biomiechani-

cal principles of strain tolerance are important). Open-wedge osteotomies (e.g., proximal tibia:

TomoFix). Peri-prosthetic fractures. Secondary fractures after intramedullary nailing. Delayed change from external fixator to definitive

internal fixation. Tumor surgery.

3) LCP in a combination of both methods(compression method and internal fixator(bridging) method) using one plate:

Articular fracture with a multifragmentary fractureextension into the diaphysis: anatomical reductionand interfragmentary compression of the articularcomponent, bridging of the reconstructed joint blockto the diaphysis.

Specific indications for the different techniques

Compression Bridging Combination

Simple diaphyseal fractures + (+)*

Simple metaphyseal fractures + (+)*

Multifragmentary diaphyseal fractures + Nocompression!

Multifragmentary metaphyseal fractures + Nocompression!

Osteotomies + +

Articular fractures +No bridging!

Articular fractures with multifragmentary meta-or diaphyseal fracutres

+

Segmental fractures

with two different fracture patterns +

Table 1: Specific indications for the different techniques in plate osteosynthesis. Newer clinical experience has shown anuneventful bone healing also after bridging of simple fractures with internal fixator principle.

Injury 2003, Vol. 34, Suppl. 2

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Segmental fracture with two different fracture pat-terns (one simple and one multifragmentary): con-ventional technique, compression principle for thesimple and bridging technique, internal fixator prin-ciple for the multifragmentary fracture.The term combination describes the combination of

two biomechanical principles: use of a combination ofinterfragmentary compression and the internal-fixatormethod (bridging). Note: Acombination technique doesnot mean combining different types of screws! Thishybrid use of both types of screws are recomented sometimes for the reduction of a fragment onto the bone orto correct the malaligment of the plate on bone axis.

On the femur and tibia, the LCP is indicated as analternative method to intramedullary nailing and otherfixation techniques, especially in cases of: Extension of the fracture into the joint. Multifragmentary shaft and metaphyseal fractures.

Narrow as well as very large medullary canals. P e-existing bone deformity.r Shaft fractures in children. Polytrauma, severe brain or thoracic injury. Simple shaft and metaphyseal fractures with soft tis-

sue compromise.

Notes for the different surgical techniques

The LCP with combination holes can be used, depend-ing on the fracture situation, in a conventional technique(compression methode). The surgical technique andinstruments are similar to conventional plating with theDCP or LC DCP.

After open, direct, precise reduction and preshapingof the plate, the interfragmentary compression isachieved by eccentric cortical screw setting in the DCpart of the combination hole of the LCP (Fig. 1). Frac-ture compression can also be accomplished with a tnsiondevice. Interfragmentary compression can also beaccomplished with insertion of a plate lagging screweither to compress a simple fractureline in the meta- ordiaphyseal segment or an intra-articular fracture.

The additional cortical screws are again used toincrease the friction between the plate and the bone. Incases of good bone quality and through an open

approach (accurate plate contouring possible), conven-tional screws may be inserted.The additional stability with the LCPis achieved with

locking head screws. These locking screws are support-ing reduction and compression created by the lag screwswithout creating uncontrolled forces by pressing the

Fig.1a: AP. and lateral view, open (1)shaft fracture of the forearm, 19-year-oldfemal, fall from the high.

Fig.1b: Stabilisation of the ulna shaftfracture with an 8-hole 3.5 LCP, con-ventional technique compressionprinciple. Two cortex screws (placedeccentrically in the DC part of thecombination hole) are used to com-press the fracture. The radius shaftfracture was fixed with an elasticintramedullary nail. FU 1 year afteroperation shows solid bone healingof both fractures.

Fig. 1c: AP and lateral view afterremovable of the hardware.

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Fig. 2: If the LCP is used in a compression mode, two cortexscrews (placed eccentrically in the DC part of the combinationhole) are used to compress the fracture. The operative tech-nique is much the same as in conventional plating (anatomi-cal reduction, inter-fragmentary compression), whereby con-ventional instruments and screws are used.In case of good bone quality, the additional cortex screws addto the stability of the construct by increasing the friction

between plate and bone.Three bicortical conventional screws (not locking head screws)on each side of the fracture are effective.In osteoporotic bone, the stability is increased by using lock-ing head screws:In osteoporotic bone, locking head screws should be used

because they increase the stability of the bone-implant-inter-face; three LHS on each side of the fracture are advised,whereby at least one bicortical LHS should be used (a mini-

mum of four cortices on either side of the fracture).By using monocortical locking head screws, the opposite cor-tex is not weakened (no drill hole), hence reducing the risk ofrefracture after implant removal.

Fig. 3: If the LCP is used as a neutralization plate, fracturereduction and interfragmentary compression are achieved bythe lag screws (1 & 2). In case of good bone quality, the addi-tional cortex screws add to the stability by increasing the fric-tion between plate and bone.In osteoporotic bone, additional stability is achieved by insert-ing locking head screws.Locking head screws help to maintain reduction and com-pression without additionally pressing the plate against the

bone surface.

Fig. 4: When using a tension device to achieve compression,cortex screws are inserted to maintain the induced interfrag-mentary compression. The fixation of the fracture is consid-ered stable, if the friction forces eliminate all motion at the frac-ture site.The LCP with locking head screws allows optimal purchaseof the plate on the bone. The fracture is compressed with thetension device. This compression is maintained by lockinghead screws. The stability of the fixation is however not rely-ing on the friction between plate and bone, but rather on theangular stable construct thanks to the locking head screws(LHS are advised in osteoporotic bone).

Fig. 5: LCP for plating of intra-articular fractures in conven-tional technique; buttress plate.This picture illustrates one possibility to fix an intra-articularfracture using the LCP in the conventional way by reducingthe fracture to the plate.Depending on the fracture pattern, the anatomical recon-struction of the joint surface can also be achieved with plate-independent lag screws.In case of bone loss or osteoporosis, locking head screws willhelp to maintain angular stability while the standard cancel-lous bone screw provides interfragmentary compression ofthe articular components.




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plate to the bone surface. In osteoporotic bone, lockinghead screws are preferred because there is no primaryloss of reduction if the plate is not adequately contouredand there is better stability in bones of poor quality(Fig. 2). If the plate is used as a neutralization plate, thefracture reduction and the inter-fragmentary compres-sion is achieved by the lag screws (Fig. 3, 4, 5, 6).

The LCPwith combination holes can be used, depend-ing on the fracture situation, in a bridging technique(internal fixator method).

The bridge-plating technique (i.e. pure splinting) canbe applied through an open or an MIPO approach. Anindirect closed non-precise reduction is necessary usingthe LCP in a bridge-plate technique.

A long plate and adequate spacing between the lock-ing screws must be used. The longer the bridging plate,

Fig. 6a: AP and lateral radiographs of a tibial head fracture. Fig. 6b: possibility to fix an intra-articular fracture using theLCP in the conventional way by reducing the fracture to theplate buttress plate. Depending on the fracture pattern, theanatomical reconstruction of the joint surface can also beachieved with plate-independent lag screws. In case ofosteoporosis, locking head screws will help to maintainangular stability while the standard cancellous bone screwprovides interfragmentary compression of the articularcomponents.

Fig. 7: Biomechanic of Locked internal fixator (LIF): bridging technique - internal fixator principle.The plate and screws form on stable system and the stability of the fracture is dependant on the stiffness of the construct.The biomechanical behaviour of the LCP used as a bridging plate with locking screws can be compared to that of an externalfixator. A long plate and adequate spacing between the locking screws must be used.Basic rule in multifragmentary shaft fractures: indirect closed reduction main attention to: axis, length, rotation, bridging of themultifragmentary fracture with an locked internal fixator focus on fixation above and below only, relative stability > inductionof callus formation.

the better. The biomechanical behavior of a bridging

plate (i.e. pure splinting) with locking screws can becompared to that of an external fixator. (Fig. 7)

In bones of good quality, the use of monocortical lock-ing head screws is sufficient, however, at least threescrews should be inserted on either side of the fracture,in each main fragment.

It is important to avoid stress concentration at the frac-ture site, 2 or 3-plate holes in the fracture zone withoutscrews lead to stress distribution.

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Fig. 8 ae:83-year-old woman, hit by car, polytrauma and severe osteoporosis. Complex fracture of the proximal tibia, type 41-C2.Stabilization of the fracture:1. After closed reduction of the articular fracture, fixation with two separate 4.5 mm cannuiated lag screws (with washers).2. Bridging of the comminuted metaphyseal fracture zone with an 8-hole LCP T-plate 4.5/5.0 after closed alignment of length,

axis, and rotation.Fig. 8b: The separate medial and anterior wedges were not touched;Fig. 8c: FU 4 weeks post-operative, beginning of callus formation;Fig. 8d: 4 months FU;Fig. 8e: bone healing after one year.




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Fig 9: 65-year-old woman with fracture of the distal radius, type 23-C3, after fall (a). Stabilization of the fracture with an obliqueangled 3-hole LCP T-plate 3.5 (b).

Fig. 10ae:

a) 59-year-old woman, accident: fall onthe street, distal tibial fracture type 42-B1 fracture with fractured third of theproximal fibula ap and lateral view

b) post-operative radiographs, ap and lat-eral: closed, indirect reduction and fix-ation with an 11-hole 4.5/5.0 LCP(MIPPO), bridging technique internalfixator principle

c) follow-up after 6 weeks, ap and lateralview good callus formation visible

d) follow-up after one year, good bonehealing

e) after implant removal, good functionalresult

c)

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M. Wagner: General principles for the clinical use of the LCP

In osteoporotic bones, the use of locking head screws

is strongly recommended with at least three screws ineach main fragment, on either side of the fracture, ofwhich at least one must be inserted bicortically.

To apply the device as an internal fixator, temporaryspace holders can be screwed into several of the conicalholes of the plate. These space holders maintain a min-imal distance between the plate and the bone. The spaceholders may be replaced by screws during the opera-tion or may be removed once plating has been com-pleted. This procedure offers the advantage that theplate will not touch the bone at any point, thus mini-mizing the damage to the bone vascularity.

Biomechanical and clinical benefits

The main biomechanical and resulting clinical benefitsof these locked internal fixators are: The plate and screws form one stable system and the

stability of the fracture depends on the stiffness of theconstruct. No compression of the plate on the bone isrequired; this suppresses the risk of primary loss ofreduction and preserves the bone blood supply. Lock-ing the screw into the plate to ensure angular as wellas axial stability, eliminates the possibility for thescrew to toggle, slide or be dislodged and thusstrongly reduces the risk of postoperative loss ofreduction.

Fig. 11ad:a) 9-year-old male, Judo, tibia shaft fracture, Type

42-A2.b) Closed reduction and briding of the fracture with

a 9-hole 4.5/5.0 LCP, intra-operative view.c) FU 6 weeks postoperative, beginning of the

callus formation.d) Removal of the plate after 10 months, solid bone

healing




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technology of internal fixators behaves in a similar wayto the external fixator in that it gives way elastically andis thus a forgiving technology. [1, 6, 7, 13]

Locking internal fixation is a new technology that aimsto preserve biology. Its application is similar to that ofthe external fixator. It is inherently simple but requires

an open minded approach to this new methode and phi-losophy. The locked internal fixator methode is anapproach that optimizes internal fixation. It aims at sim-ple and safe handling, optimizing biological conditionsfor soft and hard tissues and at being universally applic-able. This device resembles a plate but functions like anexternal fixator that is fully implanted. This proceduresupports biological internal fixation, that is, a type ofinternal fixation that gives priority to biology overmechanics.

Fig. 12 ac:a) 72-year-old man, fall while playing tabletennis. Subcapital

proximal fracture of the left humerus, type 11-A 3.b) Open plate osteosynthesis, indirect reduction by manual

distraction. (non touch technique). Fixation was obtainedusing the LPHP. Intraoperative x-rays in different planesshow the reduced fracture and the correct positioning ofthe plate, no subacromial impingement (90 abduction).The 5-hole LPHP was proximally fixed with five and dis-tally with three locking head screws (distally one LHS wasinserted bicortically, the other two monocortically).

c) Postoperative control after 6 weeks.




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The internal fixation of bone fractures or osteotomieswith the LCP system will be the new standard for fixa-tion with plates and screws from the AO/ASIF. This newplate and screw system uniquely combines the benefitsof both the conventional technique (compression meth-ode) and of the bridging the fracture zone in the MIPO

technique. (internal fixator methode) [1, 12, and 13].Using the LCP in the conventional technique (compres-sion methode pincipiple of absolute stability), it is sim-ilar to the technique using standard plate and screw sys-tem. In the bridging , we use the LCP in the internal fix-ator method (principle of relative stability) with lockinghead screws. Using these different principles of fracturetreatment leads to different types of fracture healing.

Choosing to use a LCP depends on bone quality, frac-ture situation, anatomical region and the surgeons pref-erence.

The LCPcombines two methods and techniques in oneimplant. By making the correct decision in using the LCPin specific cases, one can significantly contribute to theimprovement of the clinical outcome of the operativetreatment of bone fractures. Promising early clinicalresults have already been published.

References

1. Frigg R. Locking Compresssion Plate (LCP). An osteosyn-thesis plate based on the Dynamic Compression Plate andthe Point Contact Fixator (PC-Fix). Injury. 2001;32(suppl2):63-66.

2. Gautier E, Ganz R. Die biologische Plattenosteosynthese[The biological plate osteosynthesis]. Zentralbl Chir.1994;119:564-572.

3. Leunig M, Hertel R, Siebenrock K, Balmer F, Mast J, GanzR. The evaluation of indirect reduction techniques for thetreatment of fractures. Clin Orthop. 2001;375:7-314.

4. Perren SM, Russenberger M, Steinemann S, Mller ME,Allgwer M. A dynamic compression plate. Acta OrthopScand. 1969;125(suppl):31-41.

5. Perren SM, Schlegel U. Surgical aspects of implants andinfections. Arch Orthop Trauma Surg. 1990;109:330-333.

6. Perren SM. Evolution of the internal fixation of long bonefractures. The scientific basis of biological internal fixation:choosing a new balance between stability and biology.J Bone Joint Surg Br. 2002;84-B:1093-1110.

7. Perren SM. Evolution and rational of locked internal fixa-tor technology. Introductory remarks. Injury. 2001;32(suppl 2):S-B3-9.

8. Perren SM. Point contact fixator: part I. Scientificbackground, design and application. Injury. 1995;22(suppl1):1-10.

9. Redi TP, Murphy WM, eds. AO Principles of FractureManagement. Stuttgart-New York: Thieme; 2000.

10. Schandelmaier P, Stephan C, Reimers N, Krettek C. LISSosteosynthesis for distal fractures of the femur. TraumaBerufskrankh. 1999;l:392-397.

11. Tepic S, Perren SM. The biomechanics of the PC-Fix inter-nal fixator. 1995;26(suppl 2):5-10.

12. Wagner M, Frigg R. Locking Compression Plate (LCP): Einneuer AO-Standard. OP-Jurnal. 2000;16(3):238-243.

13. Wagner M, ed. LCP: Locking Compression Plate. [AOteaching series on CD-ROM]. Davos, Switzerland: AOInternational; 2002.

Correspondence address:Prof. Michael WagnerKlinik fr Trauma and Sportmedizin, Wilhelminen-spital Wien, Montleardstr. 37, 1171 Wien, Austria

e-mail: [email protected]

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