5/31/15. The Problem. Every Decade We Change Our Minds The Journey Around the Notch. Life is full of Compromises. 50 years ago..

Transcription

1 The Problem Surgical Treatment of ACL Tears Optimizing Femoral Tunnel Positioning Andrew D. Pearle, MD Associate Attending Orthopedic Surgeon Sports Medicine and Shoulder Service Hospital for Special Surgery Director, HSS CAS Center ACL footprint area is 3.5 x the size of the midsubstance of the ACL Harner Arthroscopy 1999 Proximal ACL is flat (9-16 mm x 2-4mm) Siebold KSSTA mm slot between notch and PCL thru which ACL must fit Triantafyllidi Arthroscopy 2013 Discrepancy between size and shape of femoral footprint and midsubstance of the ACL Life is full of Compromises ACL footprint area is 3.5 x the size of the midsubstance of the ACL Harner Arthroscopy mm tunnel - area 79 mm 2 Femoral footprint area ranges mm 2 Kopf KSSTA 2009 Can t fill the footprint Must be strategic!! Every Decade We Change Our Minds The Journey Around the Notch 1980s Isometric 1990s Transtibial 2000s Anatomic 2015 and beyond IDEAL?? Definitions Ridge 50 years ago.. Isometric concept 1960s - full range of knee motion can be achieved without causing ligament elongation and plastic deformation Artmann & Wirth- found the isometric point 1

2 Optimizing Isometry Guided Tunnel Positioning in 1980s Hefzy, Grood & Noyes The Drift Up the wall 1990s Transtibial Endoscopic Use of an Endoscopic Aimer for Femoral Tunnel Placement in Anterior Cruciate Ligament Reconstruction David A. McGuire, M.D., Stephen D. Hendricks, and Geri L. Grinstead, Ph.D. Arthroscopy 1996 Definitive Landmarks for Reproducible Tibial Tunnel Placement in Anterior Cruciate Ligament Reconstruction Craig D. Morgan, M.D., Victor R. Kalman, D.O., and Daniel M. Grawl, P.A.C. Arthroscopy 1995 Center of tunnel at over the top position 6-8 mm anterior to the truck back wall, extreme post cortex; at the junction of the roof & the lateral wall of the femoral intercondylar notch, resulting in a 1-2 mm proximal cortical margin (back wall thickness) Transtibial Results Often Impressive Overall satisfactory outcomes Harner JBJS % good and excellent results Dynamic kinematic evaluation Concerns led to reevaluation of tunnel position Logan (Vertically open MRI) AJSM 04 After ACL reconstruction, lateral tibial plateau displaced anteriorly relative to the femur by 5 mm Tashman, Anderson AJSM 04 Abnormal rotational knee motion during running after ACL reconstruction Reconstructed knee more ER and adducted Tashman CORR 07 ACL reconstruction failed to restore normal rotational knee kinematics during dynamic loading and some degradation of graft function occurred Gill, Li AJSM 06 Anterior translation of reconstructed knee compared to intact (3mm) Increased ER beyong 30 degrees flexion Chouliaras Geogoulis AJSM 07 Sig increased tibial rotation compared with controls Standard ACL reconstruction fails to restore normal knee kinematics Biomechanical Data 30 trans2bial ACL Femoral socket too high and outside femoral footprint Above the ridge Lim et al. Clin Orthop Surg 2012 Driscoll, Noble et al. Arthroscopy 2012 Debandi, Fu et al. Arthroscopy 2012 Kondo, Amis et al. AJSM 2011 Bedi et al. Arthroscopy 2011 Placing the graft in the center of the footprint restores AP and rotational stability more than vertical nonanatomic grafts 2

3 The Drift Down Concerns Higher forces on graft with lower position Anatomic Approach Fill the footprint or CENTRALIZE within the footprint Avoid high Nonanatomic position Clinical Outcomes Clinical Outcomes Journal of Arthroscopy Jan 2013 AM 5.6% TT 3.2% Did we take it too far? Too Low on the Wall? 2 incision technique 1980s Transtibial endoscopic 1990s AM portal anatomic 2000s 9,239 ACLR s from Danish Knee Ligament Registry 1945 AM and 6430 TT Primary ACLR s The Anatomy Re- Revisited Footprint fibers are not all created equally! Histology Direct and Indirect types of ACL fiber insertions Flat insertion; Not 2 bundles Stout band of fibers at the ridge with wispy posterior extension Direct Indirect 3

4 High (Direct) ACL Footprint Insertion At the ridge Direct insertion of ACL fibers histologic More robust fibers macroscopically Ideal to make the femoral tunnel at the direct insertion Biomechanically not proven Low (indirect) ACL Footprint Insertion Fan like expanse of fibers Posterior to direct insertion blending with posterior articular cartilage. Simpler ultrastructure Ligament directly anchors to bone without transition zone (smcl) Strength theoretically weaker than direct Biomechanical Study (Pearle et al) Or Within Anatomic Region of ACL femoral footprint: High ACL Fibers Inserting on the Ridge - Carry the Greatest Loads (80%) during stability exam - Are Most Isometric during ROM Conclusion AMB PLB It would appear wise to avoid going too low on the wall when performing anatomic AM portal ACLR Our data suggests that femoral tunnel placement encroaching on the ridge may be a good idea 4

5 Reconstruction most functional and isometric region of ACL Reconstruction most functional and isometric region of ACL Reconstruction of most functional and isometric region of the ACL footprint Recommended Position Based on Anatomic, Histologic, and Biomechanical Data Tunnel should encroach on ridge!! Anatomic but in the most functional portion of the footprint Covers the direct fibers Optimizes isometry (minimizes tension on graft during ROM) Time-honored approach I.D.E.A.L Femoral Tunnel Position Thank You Isometric Direct Insertion Eccentrically located in footprint Encroaching the ridge Anatomic In most functional portion of footprint Low Tension throughout ROM 5