Why anteromedial portal is the best

Transcription

1 Controversies in ACL Reconstruction Why anteromedial portal is the best Robert A. Gallo, MD Associate Professor Nothing to disclose Case presentation 20-year-old Division III track athlete sustained ACL tear Transtibial ACL reconstruction using patellar tendon autograft Returns to track but Knee doesn t feel right Difficulty playing soccer Not bad enough to undergo another surgery Sound familiar? Advances in ACL reconstruction Open, extraarticular reconstruction Prolonged immobilization Transtibial drilling Arthoscopic intra-articular reconstruction Early restoration of motion Anteromedial drilling 1

2 Goals of ACL reconstruction anatomy biomechanics function What they try to tell us ACL reconstructions performed via transtibial drilling is equivalent in 1. Recreating native anatomy 2. Restoring normal biomechanics 3. Returning function Is this borne out in the literature? Recreating native anatomy CT scans of 32 ACLrecon knees Femoral tunnel = anterior Tibial tunnel = posteromedial 2

3 Recreating native anatomy Drilling by transtibial technique produces most vertical and longest tunnels. Independent drilling technique produce most anatomic tunnels AM technique placed 97.7% of tunnel within native femoral footprint significantly more than 61.2% for the TT technique. Recreating native anatomy 30 prospectively enrolled, AM or TT Both techniques can restore femoral footprint TT must alter tibial tunnel position Recreating native anatomy Perhaps you can restore native anatomy, but at extreme angles 90º flexion required to prevent back wall compromise At 90º flexion, tibial aperture 14.1 mm from joint line 3

4 Recreating native anatomy Consequences of compromising tibial tunnel position Cyst formation beneath medial compartment Drilling into medial compartment Recreating native anatomy Conclusions about recreating anatomy: AM portal drilling appears to be better able to simultaneously recreate anatomic femoral and tibial ACL footprints TT drilling can recreate footprints but requires shallow tibial socket 1.4 mm from medial joint line Restoring normal biomechanics 4

5 Restoring normal biomechanics Restoring normal biomechanics Translation: AM = TT Rotation : AM < TT AM translation and rotation closely followed native ACL medial compartment contact area in AM Restoring normal biomechanics Conclusions about restoring biomechanics: AM portal drilling appears to be better able to restore: rotational stability in some studies, anterior translational stability 5

6 Restoring function CONTROLLED STUDIES Azboy I, Arch Orthop Trauma Surg, 2014 Hussein M, Am J Sports Med, 2012 Zheng Q, Acta Cir Bras, 2012 Alentoen-Geli E, Int Orthop, 2010 TT AM TT AM TT AM TT AM No Laxity n/a n/a 2.0 ± ± ± 1.96 ± 1.9 ± 0.2 ±1.6 (mm) mm mm 0.91 mm 1.02 mm 1.8mm mm Grade % 86.7% 41.7% 66.7% n/a n/a 41.2% 79.2% Pivot shift Normal 61.8% 66.7% 79.2% 88.5% n/a n/a 33.3% 73.1% IKDC Lysholm score n/a n/a 90.9 ± ± ± ± ± ± 2.3 Tegner 6.1 ± ± 1.2 n/a n/a n/a n/a 7.1 ± ± 1.6 time to return to play? (Azboy and Alentorn) Returning function No differences in KOOS AM 2.04 risk of revision Learning curve vs. strain on graft? Returning function No differences in KOOS scores but TT has 2.49 risk of repeat surgery 6

7 Returning function Conclusions about returning function: No differences in subjective IKDC, Lysholm, and Tegner scores Possible advantages to AM drilling: laxity with KT arthrometry, Lachman, and pivot shift testing objective IKDC scores time to return to play Revision surgery? Goals of ACL reconstruction ANTEROMEDIAL TRANSTIBIAL anatomy biomechanics function What are concerns with AM drilling? Potential technical problems and potential solutions Oblong femoral tunnel footprint Accessory inferomedial portal Flexible reamers Short femoral tunnels/back wall compromise Knee hyperflexion Flexible reamers Iatrogenic injury to medial femoral condyle Low-profile reamers Flexible reamers 7

8 Conclusion We can do better! Anteromedial portal drilling Better restores anatomy Better restores biomechanics Equal or better restores function Thank you 8