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?