Fractures
of
the
neck
of
the
fifth
metacarpal
bone.
Medium-term
results
in
28
cases
treated
by
percutaneous
transverse
pinning
V.
Potenza
*
,
R.
Caterini,
F.
De
Maio,
S.
Bisicchia,
P.
Farsetti
DepartmentofOrthopaedicSurgery,UniversityofRome‘TorVergata’,Rome,Italy
Fracturesofthemetacarpalbonesareverycommoninjuriesof theskeletalsystemand,inapproximately50%ofthecases,involve the neck of the fifth metacarpal bone. These fractures are frequentlyobservedinactiveyoungmen,occurinthedominant handandaretypicalinjuriesofaggression(boxer’sfractures).1–3 Surgical treatment is mandatory for severely displaced and unstablefracturestoavoidimpairmentofhandfunction.Infact, malrotation or volar angulation of the metacarpal head may frequentlycausereduction inthegrip strengthand lackof full extensionofthefifthfinger.3–7Theresultsofsurgicaltreatment seemtobeinfluencedbythepreoperativeconditionofthesoft tissuesofthehand;therefore,infracturesassociatedwith soft-tissue injuries, most authors suggest minimising the surgical traumasoastoobtainbetterresults.3,6
BerkmanandMiles8firstdescribedtransversewirefixationto intact metacarpals for treatment of unstable fractures of the metacarpalbones.Thepurposeofthisretrospectivestudywasto report the medium-term results in 28 patients affected by
displaced fracture of the neck of the fifth metacarpal (boxer’s fracture),withanassociatedsevereswellingofthesurrounding soft tissues, who were treated by percutaneous transverse pinning.8
Materialsandmethods
In a pool of 88 consecutive fractures of the metacarpals surgicallytreatedatourhospitalbetween2004and2008,44were displacedfracturesoftheneckofthefifthmetacarpalbone(boxer’s fracture). At diagnosis, 35 of these fractures showed a severe swelling of the surroundingsoft tissues; they weretreated by closedreductionandpercutaneoustransverseK-wirepinning.All 35 patients were invited to our hospital for a clinical and radiological follow-up, but only 28 were able to return for examination.Therewere25maleandthreefemalepatients;the righthandwasinvolvedin24casesandtheleftinfour.Theaverage age of the patients was 38.4 years (range 15–71 years). The mechanism of trauma was a direct blowin 25 patients and a scooteraccidentinthree.Inallpatients,arotationaldeformityof thefifthfingerand/ora palmarangulation ofthefracture308 were present. Rotational displacement of the fifth ray was
Injury,Int.J.CareInjured43(2012)242–245
ARTICLE INFO Articlehistory: Accepted27October2011 Keywords: Boxer’sfracture Transversepinning Metacarpalneckfracture
ABSTRACT
Thepurposeofthisstudywas toreportthemedium-termresultsin28patientsaffectedbyclosed
displacedfracturesoftheneckofthefifthmetacarpalbone(boxer’sfracture)withanassociatedsevere
swellingofthehand,whoweretreatedwithpercutaneoustransverseK-wirepinning,toverifythe
effectivenessofthissurgicaltreatment.Weoptedforthistreatmentinallcasesinwhichmalrotationof
thefifthfingerandvolarangulationofthemetacarpalheadgreaterthan308wereassociatedwitha
severeswellingofthehand.Allthepatientswerereviewedclinicallyandradiologicallyatanaverageof
25monthsaftersurgery.Atthefinalfollow-up,nopatientreportedresidualpain.Allpatientshadfull
extensionofthefifthfinger,excepttwoinwhomweobservedalimitationoftheextensionofthefifth
metacarpophalangeal(MP) jointofabout108,without significantimpairmentofhandfunction.All
patientshadatleast908flexionofthefifthMPjointandfullrangeofmotionoftheinterphalangeal(IP)
joints.Nopatienthadrotationaldeformityofthefifthfingerwithadeficitofgripstrength.Atthefinal
follow-up,aresidualpalmarangulationoftheheadofthefifthmetacarpalwasfoundinthreepatients,
withameanof78.Thedisabilitiesofthearm,shoulderandhand(DASH)scalehadameanvalueof5,and
allpatientsconsideredtheirresultasgoodorexcellent.Werecommendpercutaneoustransversepinning
inallboxer’sfracturesinwhichoperativetreatmentisindicated,especiallyinpatientswithsevere
soft-tissueswelling.Thesurgicalprocedureiseasytoperform,andsurgicalresultsaregenerallygood.
ß2011ElsevierLtd.Allrightsreserved.
*Correspondingauthor.Tel.:+390620903466;fax:+390620903465. E-mailaddress:vitopotenza2@virgilio.it(V.Potenza).
ContentslistsavailableatSciVerseScienceDirect
Injury
j ou rna l h ome p a ge : w ww . e l se v i e r. co m/ l oc a te / i n j ury
0020–1383/$–seefrontmatterß2011ElsevierLtd.Allrightsreserved. doi:10.1016/j.injury.2011.10.036
evaluated clinically: malrotation of the fifth metacarpal was diagnosed when the fifth finger wasnot oriented towards the scaphoidtubercleinflexion,andifthelittlefingerwasnotparallel totheotherfingersin extension.The palmarangulationof the metacarpalheadwasmeasuredonthelatero-obliqueX-rayswitha goniometer;itmeasuredfrom458to908,withanaverageof638. Soft-tissueswellingofthehandwasconsideredseverewhenthe knucklesofthefingerswerenotclinicallydetectableandthefovea signwaspresentonthedorsumofthehand.
Thepatientswereoperatedonusingaperipheralnerveblock anaesthesia.Underfluoroscopy,weperformedaclosedreduction ofthefracturebymanipulationaccordingtotheJahssmanoeuvre9 andinternalfixationusingtwoK-wires1.5mmthick.Thefirst K-wirewasintroducedpercutaneously,proximallytothefracture andperpendiculartotheulnarborderofthehand,andfixedfrom thefifthtothefourthmetacarpalshaft,whilstthesecondK-wire wasintroduceddistallytothefractureandparalleltothefirstwire, through the fifth and the fourth metacarpal heads. Since malrotationis usually difficult toassess under fluoroscopy,we verifiedcorrectrotationclinically.Inflexion,thelittlefingershould beorientedtowardsthescaphoidtubercle,whilstinextension,the fifth fingernail should be parallel to the other fingernails. Postoperatively,thehandwasimmobilisedinashort-armsplint. Sevendaysaftersurgery,anX-rayofthehandwastakentodetect anysecondarydisplacementofthefracture.TheK-wiresandthe splintwereremovedintheoutpatientdepartmentafteranaverage periodof5weeks(range4–6weeks).
Allthepatientswerereviewedclinicallyandradiographically from13to37monthsaftersurgery(average25months).Fromthe clinicalpointof view,we evaluatedtherangeof motionof the metacarpophalangeal(MP)andinterphalangeal(IP)joints,thegrip strength, and the possible presence of malrotation of thefifth fingerandofthedropped-knucklesignwithlackofextensionof thelittlefinger.Moreover,weuseddisabilitiesofthearm,shoulder and hand (DASH) scale (0–100 points) to assess upper arm function.From theradiographic point ofview, antero-posterior (AP)andlatero-obliqueX-raysweretakentoassessthepossible presenceofaresidualdeformityofthefifthfinger.
Results
In five cases,a minor localinfection occurred at thesite of introductionoftheK-wires,anditwastreatedsuccessfullywith antibiotictherapy.Nopatientsufferedsecondarydisplacementof thefractureattheX-raytaken7daysaftersurgery.
Atthefinalfollow-up,allpatientsweresatisfiedwiththefinal result.Nopatientreportedresidualpain,andnopatientshowed thedropped-knucklesign.Allpatientsbuttwohadfullextension of thefifth finger. In those two patients, we observed a slight limitationoftheextensionofthefifthMPjointoflessthan108, althoughtheydidnotreportanysignificantimpairmentoftheir handfunction.Allpatientshadatleast908flexionofthefifthMP jointandfullrangeofmotionoftheIPjoints.Nopatienthadany clinicallydetectablerotationaldeformityofthefifthfinger,witha deficitofgripstrength.TheDASHscalehadameanvalueoffive points,rangingfromonetoeightpoints.
AtthefinalX-rayexamination,weneverobservednonunion, avascularnecrosis ofthefifth metacarpalhead ordegenerative signs of the fifth MPjoint. Preoperatively, the average palmar angulationoftheheadofthefifthmetacarpalwas638(range45– 908),whereasatthefinalfollow-uparesidualpalmarangulationof theheadofthefifthmetacarpalwasfoundinonlythreepatients, averaging78(range 5–138)(Fig.1). Thedifference between the value of the palmar angulation of the fifth metacarpal head, measured radiographically before and after treatment, was significant.
Discussion
The purpose of this retrospective study was to assess the medium-term clinicaland radiographic results ofpercutaneous transverse fixation with K-wires in displaced and unstable fractures of the neck of the fifth metacarpal bone (boxer’s fractures). Boxer’s fracturesarevery common injuries,2,9 which cancauseimpairmentofhandfunction.5,10,11Whentheyhealin malrotationand/orinvolarangulationofthemetacarpalhead,the resultmaybealossofthegripstrengthandanextensiondeficitof the little finger. The management of boxer’s fracture is still controversial;however,surgicaltreatmentisalwaysindicatedin severely displaced and unstable fractures. Various operative techniqueshavebeenproposedforthesurgicaltreatmentofthese fractures,1,12–15 although transversepinning, first described by BerkmanandMiles,8iscurrentlyoneofthesurgicalproceduresof choice. We report the results obtained in 28 patients with a displaced fracture of the neck of the fifth metacarpal, treated surgicallyusingpercutaneoustransversefixationwithtwoK-wires totheintactfourthmetacarpalandfollowed-upatleast13months aftersurgery.FollowingthecriteriaofAlietal.10andofBirndorf etal.,5weonlyoperatedonpatientswithrotationaldisplacement ofthefifthfingerand/orpalmarangulationofthefractureof308or more. At follow-up, no patient had any clinically detectable rotationaldeformityofthefifthfingerwithaconsequentdeficitof thegripstrength,and atthefinalradiographic examinationwe neverobservednonunion,avascularnecrosisofthefifth metacar-palheadorabnormalitiesoftheMPjoint.Inspiteofameanperiod ofimmobilisationof5weeks,onlytwopatientsshowedaminimal deficit of theextension of thelittle finger. At theradiographic examination, a mild residual palmar angulation of the fifth metacarpal headwasobservedinthree patients.None ofthese last five patients reported significantimpairmentof their hand function.Theresidualpalmarangulation,observedinthreecases, couldberelatedtothefactthatonesingleK-wire,insertedthrough thedistalfragment,mightnotcontrolrotationofthefragment.To avoidthisresidualdeformityofthefifthfinger,athirdK-wire(in additiontoonedistalandoneproximal)couldbeinsertedinthe distalfragmenttobetterstabilisethereductionobtained.Allour patients,atsurgery,presentedasevereswellingofthesurrounding softtissuesofthehand.Webelievethatthepresenceofasevere swellingofthesofttissuesofthehandisonemorereasontochoose thistypeoftreatmentwhichminimisesthesurgicaltrauma.
To the best of our knowledge, several papers have been published on the transverse K-wire fixation technique for treatmentoffracturesofthemetacarpals,6,7,16,17butno medium-or long-term results have been reported. In their short-term retrospective studywithonly 3monthsoffollow-up,Galanakis etal.6reportedexcellentfunctionalandradiographicoutcomesin a series of patients affected by unstable metacarpal fractures treated with percutaneous transverse fixation with K-wires. Winter et al.,7 in their short-term retrospective study, with a meanfollow-upof2.7months,reportedthatintheboxer’sfracture intramedullary pinning gave better functional outcomes than transversepinning,althoughtheyconcludedthatintramedullary pinning istechnicallymoredemandingthantransversepinning andthesurgeonhasamoredefinitelearningcurve.
Intramedullary pinning and internal fixation with locking plates are the other two common methods of treatment for boxer’s fracture. Recently, in a comparative study on fifth metacarpal neckfracture fixation,Faccaet al.15reported better results in the series stabilised with intramedullary K-wire in comparison to a second series treated with lockingplates and immediatemobilisation.Inthissecondseriestreatedwithlocking plates,theauthorsreportedadeficit,despiteimmediate mobilisa-tion, of the MP joint due to the adherences of the extensor
apparatus.Inaddition,theyreportedacaseofavascularnecrosisof themetacarpalheadinthesameseries.In ashort-termreview, with a mean follow-up of 9 months, Calder et al.12 reported excellent results in six patients treated for displaced boxer’s fractures,stabilisedbyamodifiedanterogradeintramedullarypin. Wedisagreewiththistreatmentbecausewebelievethatbyusing only one K-wire, although modified, the risk of a secondary rotationaldisplacementofthefractureisextremelyhigh.Foucher et al.13,14 reported excellent functional results in 62 patients affected by displaced fifth metacarpal neck fracture, surgically treatedbyclosedreductionandanterogradeinternalfixationwith threepre-bentK-wires(Bouquetosteosynthesis).Asreportedby theauthorsthemselves,thisisaverydifficultsurgicaltechnique, whichrequiresalonglearningcurve.NeitherCalderetal.12nor Foucheret al.13,14mentioned thepreoperative condition of the
surroundingsofttissueofthehand,whichgreatlyinfluencesthe outcome after surgery, as reported by other authors.8 Some authors15,18reportedgoodresultsusingaretrograde intramedul-larypinningforthetreatment ofboxer’sfracture.Inagreement withotherauthors,webelievethatretrogradefixationofthefifth metacarpal bone maycauseMP jointstiffness, witha frequent limitationoftheextensionofthefifthfinger,duetothetraumaof theextensorhoodandthecollateral ligaments duringthewire insertion.12
Thelimitationsofourstudyarethatitisaretrospectivestudy whichincludeda relativelysmallnumberofpatients,withouta control series of patients treated with a different method. However, on the basis of our final results, we believe that transversepinningfixationtotheintactfourthmetacarpalbonefor displacedboxer’sfracturesisavalidandeasysurgicaltechnique,
Fig.1.Clinicalaspectandradiographicexaminationoftherighthandina23-year-oldpatientaffectedbyaboxer’sfracturewithseveremalrotationandvolarangulationof themetacarpalhead.Severeswellingofthehandispresent(A–C).ThepatientwastreatedbyclosedreductionandpercutaneoustransverseK-wirepinningfromthefifthto theintactfourthmetacarpal(D).Atfollow-up,24monthsaftertheoperation,thepatienthadfullrangeofmotionoftherighthand.Theradiographicexaminationshows perfecthealingofthefracturewithoutmalrotationorvolarangulationofthemetacarpalhead(E–I).
V.Potenzaetal./Injury,Int.J.CareInjured43(2012)242–245 244
with minimised surgical trauma. In our opinion, anterograde intramedullarynailingusingmorethanonepinremainstheother validoptionoftreatment,althoughthissurgicaltechniqueismore difficult.Internalfixationwithplatesorretrogradeintramedullary nailingshould,ifpossible,beavoided.
Inconclusion,werecommendpercutaneoustransversepinning inall boxer’sfracturesin whichsurgery is indicated,especially whensevereswellingofthehandispresent.
Conflictofinterest
Theauthorsreportnoconflictofinterest. References
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