Anterior Cruciate Ligament (ACL) Injuries:
Treatment & Prevention
David A. Abrutyn, M.D.Sports Medicine
Shoulder & Knee Surgery
What Are We Talking About?
Anatomy
• Two Bundles: Anteromedial (AM)
• Proximal/Posterior• Anterior/Medial
Posterolateral (PL)
Significance
What Does the ACL Do?
• Functions to resist anterior translation of the tibia on the femur– AM bundle
– Provides 85% of resistance to the anterior drawer in 90o of flexion
• Resists tibial rotation– PL bundle
• Helps provide varus-valgus stability when the knee is in full extension
Why Are We Talking About It?
Background
• Second most commonly injured ligament in the knee
• Estimated to occur in 1 in 3000 people in the U.S.
• Resulting in an estimated 100,000 reconstructions a year
• 6th most common orthopaedic procedure performed in the U.S.
Gender Differences
• Female:Male Ratio 9:1 Collegiate Basketball 3.5x Soccer 2.67x
• Recreational Alpine Skiers
How Does It Happen?
• The majority of ACL injuries occur from non-contact injuries (70%)
– Pivot shift injury
– Individual decelerates
– Try to change directions abruptly or lands from a jump
– Females are 6-9 times more likely to suffer an ACL tear
What Causes ACL tears?
• Position of body during landing, cutting, pivoting
Hips & Knees are straight Landing on flat feet Puts ACL at risk
• Versus Hips & Knees bent Landing on toes Risk of ACL injury
minimized
Risk Factors
• Muscle Imbalance Hamstring/Quadriceps Poor Hamstring Strength
• Hamstring protect ACL• Quadriceps
stretch/stress ACL• Slow activation of
hamstring with pivot/landing
Risk Factors
• Anatomic Factors
Risk Factors
• Environmental Factors
Risk Factors
• Hormonal Factors ACL estrogen receptors Estrogen
• Ligament looseness• Increased in girls vs. boys• Increased @ specific times during menstrual
cycle Studies VERY inconsistent
Goals of ACL Reconstruction
• Provide stable & pain-free knee under physiologic loads
• Expedient return to previous level of function
• Help prevent future injury to meniscus & cartilage
• Prevent future degenerative arthritis?
Are We Successful?
• Risk of re-tearing after ACL reconstruction 6%
Range 3-30%• Risk of re-tearing opposite
side 12%• 50% return to competing at
same level 80% return to competitive
level
What is the Problem?
• Surgical Technique Tunnel position Fixation Graft choice
• Rehab program• Patient factors
Concomitant injuries Not all ACL injuries are the same
Principles ACL Reconstruction
• Anatomic Approach
Restore knee mechanics
Improves Rotatory stability
Tunnels drilled independently
• Sadoghi P et al Arthroscopy 2011
Trans-Tibial Approach
Rehab Principles
• Immediate Post-Op Bracing Cold Modalities Quad isometrics SLR Heel Slides
• Week 1-2 Minimal Swelling Increase ROM (0-90) Closed Kinetic Chain Activities
Rehab Principles
• 4 weeks ROM (0-120) Increase Strength Cardiovascular training Aquatic Therapy
• Weeks 5-12 Increase flexibility Continue Strengthening Neuromuscular control Running
Return To Play Criteria
• Increase strength, power and endurance 90% uninvolved leg
• Increase running & cutting to meet demands of individual sport
• Increase cardiovascular demands• Progress to partial or full sport activities
6-9 months• RTP < 7 months--15.3% retear• RTP > 7 months--5.2%
– Laboute et al, Ann Phys Med Rehab 2010
We Can’t Rush Biology
• ACL Graft Undergoes necrosis &
remodeling Revascularizes @ 8-10 weeks
• Completed in 16 weeks Cellular Proliferation 4-8 weeks Graft firmly attach to bone @ 8
weeks 1 year before graft appears
histologically normal
Can We Prevent It?
• Biomechanical factors critical
• Neuromuscular/Proprioceptive programs
• Dramatic reduction in ACL tears
• Plyometric/jump training Balance drills
Principles
• Emphasize proper jump/landing techniques
Land on balls of feet Soft landing Toe-to-heel rocking of the foot
• Decrease ground reactive forces
Knee flexed Knee forward Discourage inward buckling Chest over knees
Studies
• PEP program 80% reduction over 2 years in girls playing
soccer ages 14-18 Mandelbaum aclprevent.com
• Balance Drills Carraffa
• Jumping Drills Hewett
Summary
• ACL tears continues to increase• Not all ACL tears are the same• Anatomic Reconstruction is important• Return to play
Need to be realistic Appropriate expectations
• ACL Prevention Neuromuscular training is effective aclprevent.com
Questions?