acl reconstruction: techniques and avoiding pitfalls · questions to be answered •what is the...
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ACL Reconstruction: Techniques and Avoiding Pitfalls
Timothy Hosea, MD
University Orthopaedic Associates
www.UOANJ.com
Liberally “borrowed” images from the internet
Questions to be Answered
• What is the unique anatomy and function of the Anterior Cruciate Ligament (ACL) and how do today’s reconstruction techniques attempt to recreate it?
• What is the history of ACL reconstruction and its evolution?
• What is a current technique of an ACL reconstruction and what is its rationale?
• What are possible technical complications associated with the reconstruction?
• What are my personal preferences in reconstructing the ACL?
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Of course: Based on Current Literature
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What is our Goal?
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• To restore normal knee kinematics
– Possible source of osteoarthritis if lost (Carmont, 2011)
• Provide a pain free stable knee
• To provide an expedient return to previous level of function
Timing of ACL Surgery
• Time interval is not as important as the condition of the knee at the time of surgery
• Elective procedure (Shelbourne, AJSM, 1991) – Full ROM
– Minimal effusion
– Minimal pain
– Mentally prepared for the reconstruction and rehab
• AVOID ARTHROFIBROSIS AT ALL COSTS – Cosgarea, 1995; Shelbourne, 1997; Magit,2007
ACL function
• Anterior translation of the tibia with respect to the femur
• Prevent anterio-lateral rotation
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Embryology 45 Days gestation
Bechler, Hosea 1991
ACL Double bundle
• Anterior Medial Bundle
– Anterior stability
– Taut in flexion
• Posterior Lateral Bundle
– Rotational stability
– Taut in extension
ACL Anatomy Double Bundle
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Kopf, Fu 2012
ACL Reconstruction Techniques
• Until the 1970s, there was a significant controversy about the functional importance of the ACL
• 1970s: ACL repair – Not universally successful
• Early 1980s: Repair with augmentation
• Complete replacement of the ACL with a graft – Clancy: Bone Patella Tendon Bone (vascularized)
• JBJS, 1982
ACL Techniques
• 1990s Transtibial Technique
• Non anatomic
• Quick reproducible
• Femoral tunnel drilled with offset guide through the tibial tunnel.
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ACL Technique
• 2000s
– Anatomically placed tunnels better restore normal knee kinematics
• Tashman, 2004, 2007
– Non anatomic transtibial techniques result in high percentage of OA
• Biau, 2007; Fithian, 2005; Simon, 2015
– Postulated that initial trauma (articular cartilage damage) and tunnel placement may contribute to the onset of OA
• Kopf, Fu, 2012
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ACL Technique
• Double Bundle – Attempts to reproduce the
normal ACL anatomy • Fu etal
– Superior anterior and rotational stability • Clinical implications still unknown
• NIH clinical trails in progress
– Not indicated: • Small, native ACL (<14 mm)
• Open physes
• Narrow notch (<13 mm)
• Severe bone bruising
• Multiple ligament injuries – Fu, 2012
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Vyas, Fu 2010
ACL Technique
• Anatomic single bundle – Awareness of the
importance of anatomic placement • Increased failure of an ACL
reconstruction with non anatomic placement
– Anatomic tibial tunnel placement
– Femoral tunnel placed independent of the tibial tunnel
• Double bundle issues – Increased operating time
• Double the number of tunnels
• Complexity of passing and securing the 2 grafts
• Possibility of large bony voids in the lateral femoral condyle if revision necessary
• 6% rerupture rate – (Carmont, 2011)
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ACL technique
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Kopf, Fu 2012
Technical Aspects of ACL Reconstruction
• Position of the ACL graft is the most critical surgical variable
– Direct effect on knee biomechanics and clinical outcome
Graft Options
• Bone Patella Bone • Hamstring
• Allograft
• Advantages – Lower rate of graft failure
– Sufficient strength
– Bone plug to bone tunnel fixation
• Disadvantages – Increased anterior knee pain
– Small risk patella fractures • Freedman, Bach, 2003
Frank, JBJS, 1997
Graft Options
• Bone Patella Bone
• Hamstring • Allograft
• Advantages
– Adequate strength – Little donor morbidity
• Disadvantages – Higher rate of graft failure
• Freedman, Bach 2003 • Gifstad, 2014
– Increased laxity , functionally similar • Feller, 2002
Graft Pearl
• Size matters
– Hamstring < 8mm
• Increased failure rate – Magnussen, 2012
Surgical Technique
Femoral Notchplasty
• Femoral notch stenosis associated with ACL tears
– LaPrade, 1994, Souryal, 1988
• Increased visualization of the ACL footprint and the posterior condylar wall
Tibial Tunnel Site
• Tibial insertion:
–15 mm behind anterior border of articular surface
–Medial to attachment of anterior horn of lateral meniscus
Insertion sites
• Femoral attachment:
– Posteriorlateral aspect of the intercondylar notch on lateral femoral condyle
Femoral Tunnel Placement
Non Anatomic Single Bundle Vertical Graft
Anatomic Single Bundle
Passing the Graft
Graft Fixation
• Fixation is the weak link during the early stages of healing
• Fixation Goal
– Obtain biologic incorporation of the graft at the anatomic attachment of the ACL and restore the transition from soft tissue to fibrocartilage to calcified cartilage to bone
Fixation Choices
• Interference Screw – Most popular
– Avoid divergence away from bone plug • Divergence >15 deg
decrease in pullout strength
• Clinical studies: few failures
– Blunted screw threads for soft tissue grafts
– Bioabsorbable screws
Fixation Choices
• Endobutton
• Screw and washer
• Cross pin fixation
• Rigid Fix
Anatomic ACL Reconstruction
Poor Surgical Technique
• Vertical tunnels: poor rotational control
Non-anatomic Single Bundle
Poor Surgical Technique
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• Anterior femoral tunnel: Graft failure in flexion
Epiphyseal sparring ACL
reconstruction
Kocher, 2006, 2007
Graft Healing
• BPTB grafts: – Heal by bone plug incorporation and resembled the normal
insertion of the normal ACL
• Hamstring grafts: – Heal by fibrils of the graft penetrating the bone directly and
result in the a fibrous insertion of the tendon
• Allografts: – Slower rate of incorporation
– Greater decrease in structural properties
– Prolonged inflammatory response
Bone Tunnel Widening
• More frequent with allograft and hamstring reconstruction – Associated with accelerated,
brace free rehabilitation protocol (Vadala, 2007)
– Associated with fixation points not close to the joint (Fauno, 2005)
• No study confirms that tunnel widening has an adverse effect on ACL results – Revision is more difficult
ACL Complications
• 60-80% are surgical / technical errors – Femoral tunnel
placement
– Fixation failure or mismatch
– Untreated or unrecognized secondary insufficiencies • Morgan, 2012
Summary: ACL Reconstruction
• Anatomic tunnel placement
• Gold Standard Graft
– B-PT-B
• Hamstring graft with open growth plates or patellofemoral issues
– Semitendinosis
– Gracilis
• Always repair the meniscus