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TheSpringLigament,PTTTear,andAdultAcquiredFlatfootDeformityOnMRI

(Part2) ByWilliamRenner,M.D.

This and other topics will be discussed in:

Theposteriortibialtendonistheprimarystabi- andstabilizesthetalocalcanealnavicularjoint.lizerofthefoot.Otherstabilizersincludethe Thetarsalsinusligaments(cervicalandinteros-springligament,thetarsalsinusligamentsand seousligaments)limitmedialdeviationoftheplantarfascia.Thespringligamentcomplex talarhead.Tosurgicallycorrectflatfootde-consistsofthetibio-springcomponentofthe formitybothPTTandSpringLigamentinjuriesdeltoidligamentandthecalcaneonavicularliga-mustbeaddressed.ment,whichlimitsplantarflexionofthetalus

ThisMRINewsletterispublishedonRadiusImaging

ForEducationalPurposesOnly.NotforDistributionorReproduction.Allimagesandarticlesummariesarecompiledfrompublicsources.

Thetibio-springligamentinblueisaportionofthedeltoidligament.TheSM-CNLband(red)oftheSpringLigmentisthemostimportantportionoftheligament.InferiortotheSM-CNLbandisthemedioplantarobliqueligament(pink)andmostinferioristheinferoplantarligament(brown)

Thetibio-springligamentisaportionofthedel-toidligamentandhasawideattachmenttotheSM-CNL.Thespringligament(navicularcalcanealligament)has3componentsthatextendfromthecalcaneustothenavicular.Thesuperiormedial(SM-CNL)bandisthemostimportantportionoftheligament.InferiortotheSM-CNLbandisthemedioplantarobliqueligamentandmostinferioristheinferoplantarligament.TheSM-CNListhestrongestcomponentandshouldbeemphasizedwhenreadingMRexams.TheSM-CNLextendsfromthesustentaculumtalitothedorsalaspectofthemedialnavicular.ImmediatelysuperiortotheSM-CNListheposteriortibialtendon.Athinsynoviallayerseparatesthespringligamentandtheposteriortibialtendonandthisiscalledtheglidezone.

Frequentlythereisacombinationofposteriortibialtendoninjury,springligamentinjuryandtarsalsinusligamentinjurythatleadstoflatfootdeformityinadultsandresultsinhindfootvalgusdeformity.

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CoronalMR:Thetibio-springligament(TS)isaportionofthedeltoidligament.Attachedtothetibio-springligamentinferiorlyistheCNL(springligament,medialtotheposteriortibialtendon(PTT).

CoronalDiagram:Thetibio-springligamentinblueisaportionofthedeltoidligament.Attachedtothetibio-springligmentinferiorlyistheSM-CNLbandinred,themostimportantportionofthespringligament.Thesupe-riormedialcalcanealnavicularligament(SM-CNL)formsaslingthatholdsthetalarheadinitscorrectposition.

ThisMRINewsletterispublishedonRadiusImaging

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Axial

Diagram:SM-CNLbandoftheSpringLigment,inred,isthemostimportantportionoftheligament.Thiscanbeseenbetweenthetalarhead/neckandtheposteriortibialtendon(yellow).

Whenthesurgeonsarediscussingthespringliga-menttheyarefrequentlyreferringtothetibio-springligamentandtheSM-CNL,whichIcallthespringligamentcomplex.Infact,atearatthejunc-tionofthetibio-springligamentandtheSM-CNLisoneofthemorecommontearsandiscalledthe“springligamenttear”bythesurgeons.

ThebestMRsignsofclinicallyimportantspringliga-menttearsareincreasedsignalonPDorT2weightedimageswithintheligamentwiththickening

oftheligamentgreaterthan5mmorthinningoftheligamenttolessthan2mm.Partialorcompletetearsresultinagapwithfluidsignalwithintheligament.

InastudyofMRfindingsofspringligamenttears:100%hadincreasedsignalonT2-weightedimages,93%hadabnormalcaliber,79%hadagapwithintheligament,64%hadawavyligament,and93%hadassociatedPTTtears.

AxialMR:SM-CNLbandoftheSpringLigmentisthestrongestandmostimportantportionoftheligament.Thiscanbeseenbetweenthetalarhead/neckandtheposteriortibialten-don(PTT).

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ForEducationalPurposesOnly.NotforDistributionorReproduction.Allimagesandarticlesummariesarecompiledfrompublicsources.

T2FSCoronalMRImage:thickeningoftheSM-CNLgreaterthan5mmconsistentwithspringligamentinjury.

MRfindingsofspringligamentinjury:

TheSMbandismostcommonlyinjured.TheSMbandinjurymayshowthickeninggreaterthan5mmorbeatreticiflessthan2mm.Agapintheligamentwithfluidsignalwithinthebandisthestrongestfindingofatear.Tearsofthespringligamentareaccompaniedbyposteriortibialtendontearsin>90%ofcases,flatfootdeformity,andsinustarsussyndrome

Checklistforadultacquiredflatfootdeformity: Posteriortibialtendoninjury Springligamentcomplextearincludingtibialspringligament Sinustarsisyndrome Plantarfasciitis Tarsalcoalition:themostcommoncoalitionsarethecalcaneonavicularandthetalocalcanealcoalition