Orthopaedics & Traumatology: Surgery & Research (2013) 99, 353—360

Available online at

www.sciencedirect.com

REVIEW ARTICLE

Distal femur fractures. Surgical techniques and areview of the literature

M. Ehlinger ∗, G. Ducrot, P. Adam, F. Bonnomet

Department of Orthopaedics and Trauma Surgery, Hautepierre Teaching Hospital Center, Strasbourg Academy Hospital Group, 1,avenue Molière, 67098 Strasbourg cedex, France

Accepted: 29 October 2012

KEYWORDSDistal femur;Fracture;Supracondylar andintercondylarfracture;Internal fixation;

Summary Fractures of the distal femur are rare and severe. The estimated frequency is 0.4%with an epidemiology that varies: there is a classic bimodal distribution, with a frequency peakfor men in their 30s and a peak for elderly women; however, at present it is found predominantlyin women and in the elderly with more than 50% of patients who are over 65. The most commonmechanism is an indirect trauma on a bent knee, and more rarely direct trauma by crushing.The anatomy of the distal femur explains the three major types of fracture. Because of theanatomy of the distal femur, only surgical treatment is indicated to stabilize the fracture. A

Biomechanics non-surgical treatment is a rare option. The aim of this report was to provide an update on theexisting surgical solutions for the management of these fractures and describe details of thesurgical technique applicable to these injuries. Recent radiological, clinical and biomechanicaldata published in the literature are reported to compare different surgical options.© 2013 Elsevier Masson SAS. All rights reserved.

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Introduction

Fractures of the distal femur are rare and severe. Theestimated frequency is 0.4% of all fractures and 3% offemoral fractures [1]. A classic bimodal distribution isfound with a peak in frequency in young men (in their

30s) and elderly women (in their 70s). The usual con-text is a high energy trauma in a young patient and adomestic accident in an elderly person [1]. The gender

∗ Corresponding author.E-mail address: matthieu.ehlinger@chru-strasbourg.fr

(M. Ehlinger).

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atio has changed and today there is a majority of women1 man/2 women), and the population is also increasinglylder; mean 61 years old at fracture and over 65 in morehan half the cases [1]. Sufficient stabilization to withstandtatic loading forces on bone and dynamic muscular forcesan only be obtained with surgery. An orthopedic treat-ent is rare: it is proposed in bedridden patients and/or inatients with reduced autonomy in fractures with little or noisplacement.

The goal of this study was to provide an update on

he management of these fractures. The basic pointsf treatment are summarized. The technical details andhe indications of the different surgical treatments arehen described. Finally, recent radiological, clinical and

served.

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iomechanical results published in the literature areeported to compare the techniques.

anagement and therapeutic principles

nitial management

esides a clinical examination and a standard radiologicalxamination, a CT scan is recommended because 55% ofhese fractures are intra-articular [1]. If there is a doubtbout the presence of vascular injury, appropriate testshould be performed. It should be remembered that theresence of a distal pulse does not exclude vascular injury.emoral nerve block is indicated and recommended by sameuthors in the emergency room [2]. These fractures are seri-us with a high mortality rate in elderly populations which isomparable to that found in the proximal femur. It has beenhown that a delay in surgery by more than 4 days (what-ver the cause) is associated with an increase in mortalityt 6 and 12 months of follow-up [3]. The known risk fac-ors are dementia as well as cardiac and kidney disorders3]. To reduce perioperative morbidity and mortality in thisge group, Kammerlander et al. [4] advise appropriate ini-ial medical management and taking measures to preventomplications that may compromise functional results. In aeries of 43 patients in their 80s, they reported 50% mortalityt the 5-year follow-up, a frequent loss of independence,nd only 18% of patients who can walk without help.

he major principles of treatment

ractures of the distal femur are severe and medicalanagement and treatment are difficult. The 1988 SOF-OT symposium reported [5]: infection and septic nonunion

n 13% (29% of open fractures), aseptic nonunion in4%, residual stiffness in 35%, secondary post-traumaticsteoarthritis in 50%, with initial chondral injury as well asncomplete reduction.

The main therapeutic principles are as follows. If theracture is intra-articular, joint reconstruction is the firsttep. The knee must remain free and mobile at the surgicalite. Exposure of epiphyseal fracture lines is obtained withhe knee bent, especially with frontal lines. Stabilizationn the frontal plane is usually not difficult, while saggitallane stability with rotation of the condyles is much moreifficult. The metaphyseal portion, in particular of the ante-ior cortex can serve as a reference point. The second stepncludes reducing the epiphysis on the metaphyso-diaphysis:his is performed with the leg in extension. In case of a com-inutive fracture, rotation and length should be carefully

ontrolled.

urgical options

or an extra-articular fracture, all therapeutic options are

ossible and mini-invasive surgery can be performed. In casef an intra-articular fracture, open reduction and internallate fixation should be performed with the patient on atandard operating table.

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M. Ehlinger et al.

xternal fixation

xternal fixation is not indicated for definitive treatmentf these fractures, in particular in displaced intra-articularractures. It is difficult to control alignment, the stabilityf this technique is poor (lever arm of the leg), there iso fixation of the articular component and stabilization ofhe fracture requires bridging the knee, which increases theisk of stiffness. The indications are more often for tempo-ary fixation. If there is a complex fracture, the fracture cane evaluated and a therapeutic strategy can be determinedsing this solution. A bilateral fracture or a floating kneere typical examples of these complex fractures (Fig. 1).xternal fixation provides medical management and a Dam-ge Orthopedic Control approach which reduces pain andacilitates treatment. Local monitoring of an open fractures facilitated. Finally, in case of associated vascular injury,he fracture must be stabilized rapidly.

External fixation should bridge the knee when there isntra-articular involvement. The femoral pins should be at

distance from the fracture site and the joint to preventnfection. Anterior femoral pins can be a good choice if inter-al fixation with a lateral plate is used later: in that casexternal fixation is maintained during the procedure to facil-tate control of alignment during internal fixation. Althoughemporary external fixation has certain advantages, therere still certain risks. Control of the fracture is limited,nd there is a risk of skin damage from a protruding boneragment. Oh et al. [6] reported results of a series of 59omplex intra-articular fractures with temporary bridgingxternal fixation. There were seven complications includ-ng four that developed in distal femoral fractures. Theuthors explain this rate of infection and the unsuccessfulontrol of length that occurred by the abundant femoral leguscles and the presence of the suprapatellar pouch. On

he other hand, Parekh et al. [7] reported good results inhe two-step management of complex intra-articular frac-ures around the knee (with 16 distal femoral fractures in aeries of 47 cases). Finally, Bonnevialle et al. [8] reported aeries of 27 fractures of the femoral diaphysis and 26 frac-ures of the distal femur treated with a lateral externalonoplane fixator with a high rate of infection and knee

tiffening in the ‘‘distal fracture’’ group. They concludedhat definitive external fixation is only indicated in stableistal metaphyseal-diaphyseal fractures when the epiphysisas first been stabilized.

nterograde intramedullary nailing

he indications for anterograde intramedullary nailing aressentially extra-articular fractures. Certain intra-articularractures without or with very little displacement can bereated with this technique as long as the epiphyseal partf the fracture has been stabilized with isolated screws tovoid opening of the fracture site during nailing. Finally, inhe rare cases of bi- or trifocal fractures of the distal femur,ailing is often the only therapeutic alternative (Fig. 2).

his solution is contraindicated in complex intra-articularractures.

The advantages of this technique are that it is closedith conservation of heamatoma and that the implant is

Treatment of distal femur fractures in adults 355

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Figure 1 Bilateral floating knee: a: clinical appearance; b: APX-ray, right side.

extra-articular which is relatively easy to remove. Thepatient should be installed on a traction table. If condylartraction is being performed (extra-articular fracture), thisshould be as anterior as possible. If there is intra-articularinvolvement, a traction boot is indicated. Recurvatum defor-mity of the distal fragment is controlled by providingdistal support attached to the traction table (Fig. 3). Addi-tional internal fixation of an epiphyseal fragment shouldtake into account the position of the future nail. The nailshould descend as deeply as possible into the condyle formaximum stability. Antekeier et al. [9] defined the min-imum distance between the fracture site and the mostproximal screw for distal fixation of the nail. Anterogradeintramedullary nailing is possible when the fracture islocated more than 3 cm from the proximal screw, which canresist one million cycles of loading. The diameter of the

nail is also important. For Huang et al. [10], distal corti-cal contact increases stability of the system while reducingstrains which are absorbed by the nail and the lockingscrews.

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y; c and d: postoperative X-ray, left side; e and f: postoperative

etrograde nailing

he indications for retrograde nailing are classic: extra-rticular fracture, simple intra-articular fractures withittle or no displacement. This technique may bendicated in cases of floating knee with a singleurgical approach for stabilization of both fractureites.

Passing a nail near the fractured trochlea can worsenhe situation by opening the fracture site, thus if theres an intra-articular fracture line, initial screw fixation isndicated. Retrograde nailing has the advantages of being alosed technique, but because it is intra-articular, there is

risk of septic arthritis in case of infection. Removal is alsoore difficult. The patient can be installed on a standard

r a fracture table. On a standard table, the knee is in 30◦

exion and the distal femur is supported. On a fractureable, reduction is obtained by skeletal traction at theroximal tibia with the leg hanging slightly. The nail shoulde inserted deep enough to avoid any impingement with the

356 M. Ehlinger et al.

Figure 2 Example of a bifocal fracture of the femur treated with ad, e, f: immediate postoperative X-rays.

Figure 3 Distal support attached to a traction table to controlt

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tallowing compression of the epiphyseal-metaphyseal frac-

ilting of the distal fragment.

atella and should not be used as a lever to prevent

reating an intercondylar fracture line. Epiphysealxation can be improved by using a screw and countercrew.

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nterograde intramedullary nailing: a, b, c: preoperative X-rays;

imple screw fixation

imple screw fixation is proposed in the presence of a frontalr sagittal unicondylar fracture.

A medial or lateral parapatellar approach is oftenecessary, however, in case of a fracture with no or lit-le displacement, a percutaneous procedure is possible andeduction is controlled by ligamentotaxis. A recent studyhowed that osteosynthesis using two 6.5 mm screws wereore effective than osteosynthesis using two or four 3.5 mm

crews [11]. A load of 40—56% more was required with.5 mm screws to cause system failure. In frontal fractures,he direction of the screws changes the mechanical stability.ouble screws using cancellous lag screws in a posterior tonterior direction provide better mechanical strength dur-ng loading than those in an anterior to posterior direction12].

lade plate

lassic indications are extra-articular fractures, sagittalnicondylar fractures or supracondylar and intercondylarractures.

This is a monoblock, preshaped implant that is adapted tohe anatomy of the distal femur. The system is very stable

ure site. In osteoporotic bone, placement of the bladean be traumatic and have little resistance to breakage.echanically, the plate functions like a dynamic tension

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Treatment of distal femur fractures in adults

band and creates medial compression. The 95◦ blade plate isplaced on a femur whose articular surface is in 1—3◦ valgus.In this way, the difference in angle between the plate andthe distal end of the femur results in medial compressionof the metaphyseal fracture site after diaphyseal fixation,thanks to the deformation of the blade plate. For an optimaleffect, the medial pillar must be perfectly reconstructed.The diaphyseal position of the plate is determined by theposition of the blade which must be precisely defined. Itshould be located 2 cm from the joint line (AP and lateralview), along the axis of the femoral diaphysis and in the mid-dle of the anterior half of the largest diameter of the condylein profile. Thus the blade is inserted in front of the Blumen-satt line (avoiding the cruciate ligaments) and behind thegroove of the trochlea (avoiding the patellofemoral jointline). The path is perpendicular to the lateral cortex, aimedapproximately a dozen degrees towards the back to preventinternal rotation and medial translation of the distal frag-ment. The blade should not extend beyond the medial cortexto prevent injuries of the medial collateral ligament.

Dynamic compression plate

The indications are classic: extra-articular fractures,sagittal unicondylar fractures or supra- and intercondylarfractures.

This solution includes dynamic epiphyseal screw fixation(lag screw) for compression of the fracture site. Epiphy-seal fixation is obtained by a single screw which the platepivots upon for sagittal adjustment. The 95◦ angle betweenthe plate and the screw facilitates frontal placement andpositions the ephiphyseal screw parallel to the joint. Thissystem has the advantage of being fairly easy to position,because the screw is cannulated, to limit bone trauma andto have good resistance to screw failure. However the screwhole is large, there may be rotational instability in the dis-tal screw before diaphyseal fixation and the insertion site ofthe screw may be located near a frontal fracture. The inser-tion guide is positioned according to the same criteria as theblade plate, and its direction on the axial plane is parallel tothe anterior trochlear rims, or 10◦ downwards and inwards.

Locking compression plate

The classic indications are extra-articular fractures, sagittalunicondylar fractures or supra- and intercondylar fractures.

The goal of locking plate is to provide better stability infragile bone. Primary stability of the plate is independentof the friction effect as the screw presses the plate, and isobtained by locking the screw into the plate. Plate design isusually anatomical which allows it to be used as a ‘‘reductionmold’’, molding the bone to the plate.

The locking plate can be used during an open procedurewhen there is intra-articular involvement, or with mini-invasive surgery using the ancillary less invasive stabilizationsystem (LISS) in case of an extra-articular fracture or in thepresence of a simple non- displaced fracture [13]. Combina-

tion use is possible, with mini-invasive proximal diaphysealfixation combined with open distal internal fixation. Mini-invasive surgery reduces postoperative pain, and facilitatesfunctional recovery [14]. Its main disadvantage is the lack

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f epiphyseal compression with locking screws, requiringrior placement of standard additional screws. These screwshould not interfere with the plate. The rules for fixation ofhis system must be strictly followed, in particular duringini-invasive surgery to prevent malunion and mechanical

ailure [15]. The patient can be installed according to theurgeon’s preference. If the patient is installed on a tractionable, traction should be moderate and a certain degree ofmpaction of the fragments should be preserved, especiallyn elderly patients to promote union. The first step of theini-invasive surgery is to mark the skin with references

fracture, joint line, patella, femoral stems of an existingmplant, femoral axis, incision) which will help reduce themount of radiation to the patient, choose the length of thelate and facilitate the procedure. The lateral paracondylarpproach is used. The length of the plate is chosen to leavet least five holes above the fracture. The goal is to obtainoverage that is as long as possible to absorb and distributetrains and stresses. It is necessary to remain extra-articulary raising the suprapatellar pouch. The beveled tip of thelate allows minimally traumatic submuscular and extrape-iosteal insertion. The plate should be parallel to the lateralortex in front, centered on the femoral diaphysis in profile,ith the racket of the distal femoral plate located behind

he base of the trochlea and in front of the Blumensatt line.he anatomical plate can be used as a reduction mold if andnly if the plate is, firstly, parallel to the lateral cortex ofhe femur (parallel to the cortex does not mean in contactith bone), secondly, the epiphyseal screws are parallel to

he joint line. The second part of the procedure includeslacing a 2 mm pin along the path of the central screw ofhe LISS system which should be parallel to the joint line.he bone can then be pulled towards the plate with a trac-ion screw or by using the LISS system. To obtain a perfecteduction, different technical tricks can be used (lag screwrom the bone to the plate, temporary intrafocal pinning,emporary screws, joystick pin) [13—15].

Numerous biomechanical studies have been performedo evaluate and define locking plate fixation systems.he LCP® (Synthes, Etupes, France) system is usually theeference and is compared to classic internal fixation sys-ems. Dougherty et al. [16] suggest that bicortical screwshould be systematically used to provide three points ofxation (2 cortical + the plate) to limit breakage. The posi-ion of the screw in relation to the fracture line depends onhe type of fracture. If the fracture is unstable (long frac-ure line, comminutive fracture) locking screws are placedear the fracture line to stabilize the fracture site. If it is

simple fracture, locking screws are placed further awayith an open hole on each side of the fracture to createlasticity in the system, which will promote union [17]. Forhmad et al. [18], the internal fixation system should belose to the fracture. A distance of less than 2 mm providesetter resistance to compression and torsion, while theres significant plastic deformity with more than 5 mm. LCPlates have combination screw holes making it possible tose a ‘‘locked system’’, a dynamic compression plate (DCP)ystem or a ‘‘combination’’ system. Stoeffel et al. [19] com-

ared these three systems. The locking system results iness loss of reduction under axial compression with less plas-ic deformity and the DCP system provides better strengthnder torsion. The authors propose combination fixation.

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ottlang et al. [20] propose the use of a standard screw athe end of the plate in case of a fracture in osteoporotic boneo limit strains and prevent a stress fracture. This type ofystem increases strength during bending without changingtrength under compression or torsion. The implant must bearallel at a 10◦ angle to the cortex and the lateral condyle.ndeed Khalafi et al. [21] have shown that these parallel sys-ems are stronger under axial compression and cyclic loadinghan systems in which the plate is not parallel to the lateralortex. Beingessner et al. [22] compared ‘‘titanium’’ plateso steel plates as well as unicortical to bicortial screws inhese indications. They showed that strength under torsions reduced in ‘‘titanium’’ plates and strength is improvedith bicortical screws. On the other hand, there is no dif-

erence for axial compression strains and plastic deformity.ujan et al. [23] concluded that ‘‘titanium’’ plates favorhe formation of calluses by increasing elasticity in fixationaterial. Finally, for Wilkens et al. [24], the placement ofolyaxial screws increases strength under axial compressionnd torsion and reduces deformation observed under cyclicoading.

otal knee arthroplasty

s in complex fractures of the proximal humerus, the dis-al humerus and fractures of the femoral neck, total kneerthroplasties can be included as a therapeutic option inlderly patients.

This is a difficult procedure in a fragile population requir-ng extensive expertise in arthroplasty. The main technicaloint is to restore the height of the joint line when theres no longer any possibility of reduction. An intact lateralr medial pillar facilitates adjustment of the replacements.

constrained knee replacement is usually chosen and evenn certain cases a megaprosthesis such as that used afterumor resection. Postoperative morbidity-mortality is high.n a series of 54 fractures in patients in their 80s, Apple-on et al. [25] reported a mortality of 40% and a morbidityf 15% at 1 year with 11% of surgical revisions and 4% ofmplant revisions. Patient selection is essential to guaranteehe best results. Finally, certain authors propose a hingedrosthesis to treat nonunion of the distal femur in elderlyatients. After a mean follow-up of 4 years in a series of 10atients mean age 74 years old, Vaishya et al. [26] reportedatisfactory functional results with a very low morbidity inight patients. Haidukewych et al. [27] proposed a totalnee replacement for nonunion of the distal femur as well asor early failure of internal fixation. Survival was 91%, after

years in 15 patients with perioperative complications in9%, postoperative complications in 29%, and poorer resultshan for primary replacements.

esults in the literature

iomechanical data

everal biomechanical studies have shown that locking sys-

ems are better than classic internal fixation (DCP plate,etrograde nailing, blade plate) [28—30]. Fulkerson et al.28] compared locking plates to classic large fragment platesith cables. Strength under axial compression and torsion

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M. Ehlinger et al.

as increased in locking plates, however failures were moreevere with opening of the proximal femoral fragment.lowodzki et al. [29] compared LCP, blade plates, and ret-ograde nailing in extra-articular fractures. Strength underxial compression was better with the LCP system than withhe blade plate or nailing, by 34 and 13% respectively, buttrength under torsion was reduced. The authors observedetter distal fixation with the LCP system with loss of dis-al fixation in only one LCP plate (6%), three blade plates38%) and eight losses with retrograde intramedullary nail-ng (100%). These same authors compared the blade plate tohe LCP system in cadavers with high bone density and didot find any significant difference in compression strength30]. Finally, Hingins et al. [31] concluded that the lockinglate system was better than the blade plate with increasedtrength under axial compression and cyclic loading what-ver the quality of cadaveric bone. To our knowledge, notudies have been performed to compare anteretrogradentramedullary nailing to locking plates. Overall, biome-hanical results showed that locking plates are better.

linical results

allier and Immler [32] compared the 95◦ blade platend LCP locking plates in a retrospective series of 71ntra-articular and extra-articular fractures. The rates ofomplications, surgical revisions and nonunion were statisti-ally higher with LCP plates. On the other hand, Nayak et al.33] support the use of LCP locking plates for extra-articularractures, reporting union in all cases, good recovery oflignment and high quality function. An autologous graft wasot necessary with the mini-invasive technique, postopera-ive pain was reduced and the rate of union was high. Kolbt al. [34] confirmed these results in a retrospective seriesf 50 fractures. Functional recovery was found to be veryood with 80% of good and very good results. They concludedhat the locking plate system allows early mobility, rapidunctional recovery and good radiological results with loworbidity, even though these were intra-articular fractures.anabar et al. [35] and Kavali et al. [36] proposed fixation ofomplex fractures of the distal femur with locking plates byini-invasive approach emphasizing the limited blood loss

nd low rate of complications. Kavali et al. [36] did not findny statistical difference in functional recovery betweenatients treated for single or multiple fractures. Compar-sons in the literature between retrograde intramedullaryailing and blade plate by a mini-invasive approach haveot shown any difference between intra-articular or extra-rticular fractures. Markmiller et al. [37] did not reportmproved results for any particular implant for identicalndications. Hierholzer et al. [38] confirmed these resultsn a retrospective series of 115 fractures comparing retro-rade nailing (n = 59) and mini-invasive locking plate (n = 56).he authors describe the indications for each technique:he plate can be adapted to all fractures, while retrogradeailing is better adapted to extra-articular fractures. Theymphasize that high quality results are more dependent

pon the surgical technique than the choice of implant.n the other hand, results comparing retrograde nailingnd classic open internal fixation are clear. For Thomp-on et al. [39], statistical results for the rate of surgical

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Treatment of distal femur fractures in adults

revision and the rate of malunion are better for retrogradeintramedullary nailing. The rates of infection and nonunionwere higher in the open internal fixation group. After amean follow-up of 6 years nearly 50% of intra-articularfractures showed progression to arthritis on radiologicalimaging. Acharya et Rao [40] reported a prospective seriesin 28 patients treated with retrograde nailing with unionin 93%, malunion in 14% and excellent or good functionalresults in 75% of cases. There was no difference betweenresults for retro- and anteretrograde nailing. For Salemet al. [41], results in length, torsion, alignment and functionwere comparable. The only reported difference was in hiprange of motion which was more limited with anteretrogradeintramedullary nailing, and knee range of motion whichwas more limited with retrograde nailing. Hartin et al. [42]did not observe any difference in functional recovery in arandomized comparison of the treatment of extra-articularfractures by retrograde intramedullary nailing and bladeplate. The only element observed was more frequent painin the knee in the retrograde nailing group, so that fixa-tion material had to be removed in 25% of the cases. Theresults in the literature do not provide any consensus on thetechnique — only closed techniques seem to make a differ-ence. It is important to remember that the best results areobtained with techniques in which the surgeon has the mostexperience.

Conclusion

The quality of the surgical technique is the primary fac-tor, and the only guarantee of obtaining good radiologicaland clinical results in distal femoral fractures. Mini-invasivetreatment (nailing or plates) seems to provide better results.All types of fractures can be treated with locking platesand a classic or mini-invasive surgical approach is possi-ble. Although the overall mid-term results are satisfactory,there are no studies evaluating the long-term functional andradiological results of fractures of the distal femur. However,there seems to be a tendency towards progression to arthri-tis in intra-articular fractures. Recent biomechanical studieshave shown that results are better with locking plates. Thesurgical technique must be rigorous and the biomechanicalqualities of these implants must be understood to preventthe development of major complications.

Disclosure of interest

ME, PA: occasional consultant for Synthes®.

Appendix A. Supplementary data

Supplementary data associated with this article can befound, in the online version, at http://dx.doi.org/10.1016/j.otsr.2012.10.014.

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