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Knee Stability Symposia: Check The Slope in Failed ACLRs

AAOS 2017AOSSM Specialty Day

RobertF.LaPrade,M.D.,Ph.D.Chief Medical Officer

Steadman Philippon Research InstituteCo-Director, Sports Medicine Fellowship

Complex Knee and Sports Medicine SurgeonThe Steadman Clinic Vail, CO

Adjunct Professor, University of MinnesotaAffiliate Faculty, Colorado State University

Disclosures

Etiology of ACLR Failures• Technical errors• Malalignment: Coronal and Sagittal

Planes• Recurrent trauma• Concurrent instabilities (think PLC)• Graft choices (previous)• Deficient PHMM, meniscal root

tears• Genu Recurvatum

Malalignment- SagittalPlane• Normalposteriortibial

slope=7-9°(Harner,AJSM,2007)• SlopeMeasurement:angle

betweenperpendicularlinetotibiashaftverticalaxisandlinealongtibial plateau

• Anteriortiltà ACLDknee

Medial Tibial Slope• Matsuda, J knee Surg, 1999• Mean tibial posterior slope in the

medial plateau: – 10.7 degrees (range: 5 degrees - 15.5

degrees) in normal knees– 9.9 degrees (range: 1.5 degrees- 19

degrees) in varus knees

Lateral Tibial Slope• Matsuda, J knee Surg, 1999• Mean tibial posterior slope in the lateral

plateau:– 7.2 degrees (range: 0 degrees - 14.5 degrees) in

normal knees– 6 degrees (range: 1 degrees - 13 degrees) in

varus knees.

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Tibial Slope + ACL Deficiency • Todd et al, AJSM, 2010

– When compared to uninjured controls, female ACL injured cases had: o Increased lateral tibial slope (P = .03) oShallower medial tibial depth (P = .0003)

– When compared to uninjured controls, male ACL injured cases had: o Increased lateral and medial tibial slope (P = .02) oShallower medial tibial depth (P = .0004) compared

with controls

Tibial Slope + ACL Deficiency

• Christensen, AJSM, 2015– Mean LTPS in ACL failure

group 8.4º vs 6.5º in control group

– ↑ LTPS assoc with risk for early ACL graft failure

Malalignment - Sagittal Plane

• Increased posterior slope increases anterior translation of graft

• Significant increased posterior slope stretches out ACL graft

Tibial Slope Assessment on MRI• Hudek, CORR, 2009

– Mean posterior tibialslope 3.4° decreased on MRI compared with radiographs

– Mean posterior slopeo MRI: 4.8° ± 2.4°

o Radiograph: 8.2° ±2.8°

PTO & Sagittal Tibial Slope• LaPradeetal.(KSSTA,2016)

– Slopemeasuredatpreop,immediatepostop,6monthspostop

– Foundnosig.changeintibial slopeimmediatelypostop– Conclusion:Currentplatedesignsarenotsufficienttodecreasetibial slope

– Unabletoassesseffectofanteriorcorticalstapleasresultofnochangeinslope

(ChahlaandLaPrade,Arthrosc Tech,2016)

CaseBasedExample• CC: Recurrent left knee

instability after 2 failed left ACL reconstructions.

• HPI: Non-contact twisting injury to left knee while walking.

– Functional instability w/ twisting movements.

– Pain 0/10 resting, 7/10 with episodes of instability (sharp and aching)

– Cannot participate in sports

• Physical Exam– 5’ 9” and 145 lbs– ROM: - 4° to 145° bilateral– No effusion– Neurovascularly intact– 3+ Lachman – 2+ pivot shift– All other tests negative

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PreoperativeRadiographsVarus malalignmentIncreased sagittal tibial slope

~13°

PreoperativeCT

• ObtainforallACLRfailures

• Bestmeanstoassesstunnelposition/osteolysis

StagedACLrevision– 1st Stage• Stage 1:

– ACL tunnel bone grafting of femoral and tibial tunnels with allograft bone graft

– Biplanar medial opening wedge proximal tibial osteotomy with allograft bone graft

– Deep hardware removal– Decrease in slope: ~ 2 °

StagedACLrevision– 2nd Stage• Stage 2:

– Removal of plate and screws– Medial meniscal allograft

transplantation with anterior and posterior bone plug fixation

– Re-revision ACLR with BTB autograft

TeachingPoints- Alignment• Biplanar medial opening wedge proximal tibial

osteotomy in ACL deficient patients with varus malalignment:– Decreases stress on the graft

• Correct coronal plan deformity• Correct sagittal plane deformity (decrease tibial slope) (Dejour, JBJS,

1994)

– Decreased tibial slope decreases anterior tibial translation (Li, AJSM, 2014)

– Improves stability (Trojani, OTSR, 2014)

– Increases return to sport (Trojani, OTSR, 2014; Li, Arthrsocopy, 2015)

– Slows OA progression (Dejour, Clin Orth, 1994; Noyes, AJSM, 2000)

Tibial Slope + ACL Deficiency• Arun, 2016, AOTS

– Decreasing tibial slope >5º prod functional favorable outcome

– Dec tibial slope may be protective in ACL def knee

– Mean increase in IKDC:o <5º decrease in posterior tibial slope=

10.7o >5º decrease in posterior slope= 19.9

– Mean increase in Lysholm:o <5º decrease in posterior tibial slope=

10.3o >5º decrease in posterior slope= 27.1

P<0.05

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When to Increase Slope?

• When to increase slope:– Significant genu

recurvatum à Increase slope to “normal”

– Flat posterior tibialslope

Summary• ACLR revision technically demanding

• Technical errors, malalignment, and concurrent instabilities need to be assessed

• Failed ACLR with increased slope àconsider PTO to decrease slope

Steadman PhilipponResearch Institute

ThankYou