Improvedcontrolofkneelaxityafter‘dynamic’augmentationofACLsuturerepair
BiomechanicalcomparisonofthreeACLsuturerepairtechniquesinthehumancadavericknee
Roy A.G. Hoogeslag MD1 Reinoud W. Brouwer, MD, PhD2 Rianne Huis in ‘t Veld, PhD1 Joanna M. Stephen, Ph3,4 Andrew A. Amis, FREng, DSc(Eng)3,5
1Centre for Orthopaedic Surgery OCON, Hengelo, the Netherlands 2Department of Orthopaedic Surgery, Martini Hospital, Groningen, the Netherlands 3Biomechanics Group, Mechanical Engineering Department, Imperial College London, London, UK 4Fortius Clinic, Fitzhardinge Street, London, UK 5Musculoskeletal Surgery Lab, Department of Surgery & Cancer, Imperial College London School of Medicine, London, UK
INTRODUCTION
AlthoughaugmentedsuturerepairoftherupturedACLregainedinterestinthelastdecade,thereislack of objective evidence investigating how contemporary techniques affects anterior tibialtranslationacrossthefullarcofLlexion,andaftercyclicloadingoftheknee.
Abiomechanicalstudywasconductedonhumankneecadaverstocompareresultsafternon-,static-anddynamic-augmentedACLsuturerepairacrossthearcofLlexion,andaftercyclicloading.
Hypotheses1. Non-augmentedsuturerepairand
2. Static joint bridging augmentationdonot restore anterior tibial translation (ATT) compared toACL-intactvaluesacrossthearcofLlexionoftheknee,aftercyclicloading.
3. Dynamic joint bridging augmentation restores ATT compared to ACL-intact values andsigniLicantlyreducesATTcomparedtoACL-deLicientvaluesacrossthearcofLlexionoftheknee,andmaintainsthesevaluesaftercyclicloading.
ACLsuturerepairtechniques
Classic ACL suture repair technique as described by Marshall et al.: the tibial stump of the ruptured ACL is sutured and the suture wires are knotted over the femoral cortex after the suture are led through two femoral tunnels (in PL en AM attachment).
Contemporary ACL suture repair technique as described by Mackay et al.: the sutured ACL is stabi l ized with a stat ic joint br idging augmentation (Internal Brace; Arthrex); a thread through the ACL, a tibial and a femoral tunnel is fixed to the femoral cortex with a button and to the tibial cortex with an interference screw; the thread can be tightened by means of a variable loop length cortical suspension device (TightRope; Arthrex).
Contemporary ACL suture repair technique as described by Eggli et al.: the sutured ACL is stabilized with a dynamic joint bridging augmentation (Ligamys; Mathys); a thread through the ACL, a tibial and a femoral tunnel is fixed to the femoral cortex with a button and to the tibial cortex with an spring-in-screw mechanism; the thread is pretensioned before fixation in the dynamic tibial screw.
METHODS
Twelvehumancadaverickneesweremountedinatestrig,andkneekinematicsfrom0°to90°ofLlexionwererecordedbyuseofanopticaltrackingsystem.Measurementswererecordedwithoutloadandwith89-Nanteriorforce.
Thekneesweretestedinthefollowingstates:• ACL-intact• ACL-deLicient• non-augmentedsuturerepair(Marshall)after10,150and300loadingcycles• staticjointbridgingaugmentation(InternalBraceTM)after10,150and300loadingcycles,and• dynamicjointbridgingaugmentation(LigamysTM)after10,150and300loadingcycles.
Statisticalanalysisusedmixed-modelanalysiscomparingtheeffectsofstatesforATTacrossthearcofLlexion.PosthocSIDAKtestswereappliedinordertoinvestigatedifferencesacrossconditionswhilecontrollingformultiplecomparisons.LevelofsigniLicancewassetatp<0.05.
Illustration: Cuomo P, Rama KRBS, Bull AMJ, Amis AA. The Effects of Different Tensioning Strategies on Knee Laxity and Graft Tensioning After Double-Bundle Anterior Cruciate Ligament Reconstruction. AJSM 2007
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Ant
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Flexion Angle (degrees)
Intact
ACL Def
Marshall 10
Marshall 150
Marshall 300
Non-AugmentedACLSutureRepair(Marshall)after10,150and300cycles
#
ACL-de'icientstate ComparedtotheACL-deLicientstate,acrossthearcofLlexion,non-augmentedACLsuturerepair(Marshall)didnotresultinsigniLicantdecreaseofATTdirectlypostoperative(p=0.642)andaftercyclicloadingwith150(p=1.000)and300(p=1.000)cyclesofLlexionandextension.
ACL-intactstateComparedtotheACL-intactstate,acrossthearcofLlexion,non-augmentedACLsuturerepair(Marshall)resultedinasigniLicantincrease(#)ofATT after cyclic loading with 150 (p=0.003) and 300 (p=0.000) cycles of Llexion and extension; however, the increase of ATT directlypostoperative,wasnotsigniLicant,althoughitdidapproachsigniLicantvalues(p=0,068).
= significant compared to ACL def*= significant compared to ACL intact#
##
*
StaticJointBridgingAugmentation(InternalBrace)after10,150and300cycles
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0 10 20 30 40 50 60 70 80 90
Ant
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(m
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Flexion Angle (degrees)
Intact
ACL Def
Internal Brace 10
Internal Brace 150
Internal Brace 300
*
ACL-de'icientstateCompared to the ACL-deLicient state, across the arc of Llexion, static joint bridging augmentation (Internal Brace) resulted in a signiLicantdecrease(*)ofATTdirectlypostoperative(p=0.011);however,thedecreaseinATTdidnotreachsigniLicantvaluesaftercyclicloadingwith150(p=0.075)and300(p=0.223)cyclesofLlexionandextension.
ACL-intactstateComparedtotheACL-intactstate,acrossthearcofLlexion,staticjointbridgingaugmentation(InternalBrace)decreasedATTtonormalvaluesdirectlypostoperative(p=0.982)andaftercyclicloadingwith150(p=0.774)and300(p=0.364)cyclesofLlexionandextension.
= significant compared to ACL def*= significant compared to ACL intact#
*
#
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Ant
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(m
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Flexion Angle (degrees)
Intact
ACL Def
80-N Ligamys 10
80-N Ligamys 150
80-N Ligamys 300
DynamicJointBridgingAugmentation(Ligamys80-N)after10,150and300cycles
ACL-de'icientstateComparedtotheACL-deLicientstate,acrossthearcofLlexion,dynamicjointbridgingaugmentation(Ligamys)with80-Npretensioningresultedina signiLicantdecrease (*)ofATTdirectlypostoperative (p=0.000)andafter cyclic loadingwith150 (p=0.000)and300 (p=0.000) cyclesofLlexionandextension.
ACL-intactstateComparedtotheACL-intactstate,acrossthearcoffLlexion,dynamicjointbridgingaugmentation(Ligamys)with80-NpretensioningdecreasedATT to normal values directly postoperative (p=1.000) and after cyclic loadingwith 150 (p=1.000) and 300 (p=1.000) cycles of Llexion andextension.
***
= significant compared to ACL def*= significant compared to ACL intact#
*
#
DynamicJointBridgingAugmentation(Ligamys60-N)after10,150and300cycles
ACL-de'icientstateComparedtotheACL-deLicientstate,acrossthearcofLlexion,dynamicjointbridgingaugmentation(Ligamys)with60-Npretensioningresultedina signiLicantdecrease (*)ofATTdirectlypostoperative (p=0.000)andafter cyclic loadingwith150 (p=0.000)and300 (p=0.000) cyclesofLlexionandextension.
ACL-intactstateComparedtotheACL-intactstate,acrossthearcoffLlexion,dynamicjointbridgingaugmentation(Ligamys)with60-NpretensioningdecreasedATT to normal values directly postoperative (p=1.000) and after cyclic loadingwith 150 (p=1.000) and 300 (p=1.000) cycles of Llexion andextension.
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Flexion Angle (degrees)
Intact
ACL Def
60-N Ligamys 10
60-N Ligamys 150
60-N Ligamys 300
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= significant compared to ACL def*= significant compared to ACL intact#
*
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Ant
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Flexion Angle (degrees)
Intact
ACL Def
Marshall 300
Internal Brace 300
80 Ligamys 300
60 Ligamys 300
***
Non-augmented,staticaugmentedanddynamicaugmentedjointbridgingaugmentationafter300loadingcycles
#
ACL-de'icientstateCompared to the ACL-deLicient state, across the arc of Llexion, dynamic joint bridging augmentation (Ligamys) with 80-N and 60-NpretensioningresultedinasigniLicantdecrease(*)ofATTaftercyclicloadingwith300(p=0.000)cyclesofLlexionandextension.
ACL-intactstateComparedtotheACL-intactstate,acrossthearcofLlexion,non-augmentedACLsuturerepair(Marshall)resultedinasigniLicantincrease(#)ofATTaftercyclicloadingwith300(p=0.000)cyclesofLlexionandextension
= significant compared to ACL def*= significant compared to ACL intact#
#
CONCLUSION
In contrast to non-augmented ACL suture repair and static joint bridgingaugmentation, dynamic joint bridging augmentation resulted in restoration ofnormal ATT values when compared to the ACL-intact knee, and signiLicantlydecreased ATT values when compared to the ACL-deLicient knee, after cyclicloadingoftheknee,acrossthefullarcofLlexion.
ClinicalRelevance
ThisstudysuggeststhatdynamicjointbridgingaugmentationcanapproximatetherupturedendsoftheACLdirectlypostoperativeandcanmaintainthisaftercyclicloading,whichisanimportantconditiontopromotehealingoftherupturedACL.
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