Objective:Toanalyzethehistologicalresultsandthebiologicalremodelingofligamentousinsertionafterthereconstructionofanteriorcruciateligament(ACL)withautograftorallografttendon.Methods:ExtensordigitorumtendonwasharvestedfromhindlimbasgraftmaterialandtransplantedtoreconstructtheresectedACLin12mongreldogs.Eachfreetendonendwassecuredbyholdingsuturesandthenthesuturesweretiedtothepostscrewatthefemoralandtibialbonytunneloutletaftertransplantationrespectively.Autograftwasrandomlyperformedononesideofkneewhileallograftontheothersideofknee.Aftertransplantation,thehistologicalanalysiswasundertakenatthe6th,12thweeksandthe6thmonthusinghematoxylin-eosin(HE)stainunderlightmicroscope.Results:TheinsertionstructureofnormalACLtypicallyconsistedoffourlayers,i.e.,denseconnectivetissue,fibrocartilage,mineralizedfibrocartilageandbone.Therewasadistinctregulartidemarklinebetweenfibrocartilageandmineralizedfibrocartilage.Atthe6thweekpostoperativcly,looseconnectivetissuepresentedintheinterspacebetweengraftandbonytunnelwallinbothautograftandallograftgroups.Atthe12thweekpostoperatively,thecollagenousfibersbetweenautograftandtunnelwallbecamewellorganizedandthefourlayersofinsertionwithdiscontinuoustidemarklineweredemonstratedindistinctlyinautograftgroupbutnotinallograftgroup.Atthe6thmonthpostoperatively,bothofaclearandcontinuoustidemarklineanddistinctfourlayerscouldbeseeninautograftgroup.Inallograftgroup,onlyawaveddiscontinuoustidemarklinewasshownandeithertheanatomicmorphologyorthematurityofinsertionwasinferiortothatofautograftgroup.Conclusions:Atthe6thmonthpostoperatively,althoughtheligament-cartilageinsertionisprimarilyformedafterACLreconstructionwithautograftorallografttendon,thehistologicalmorphologyandthematurationofinsertionofautografttendonar
