2 nd Annual Sports Medicine Conference Don G. Aaron, Jr., MD June 8, 2013

2nd Annual Sports Medicine Conference

Don G. Aaron, Jr., MDJune 8, 2013

ACL INJURY PREVENTIONI. ACL Anatomy and FunctionII.Incidence of ACL InjuriesIII.Mechanism of InjuryIV.Risk Factors for InjuryV.Treatment and RehabilitationVI.Prevention of InjuryVII.Summary

ACL ANATOMY AND FUNCTIONAnatomy• The ACL originates at the

posteromedial aspect of the intercondylar notch on the LFC and inserts on the tibia approximately 15 mm behind the anterior articular surface just medial to the anterior horn of the lateral meniscus.

• There are 2 discrete bands – anteromedial and posterolateral.

Function• The ACL is the primary restraint

to anterior translation of the tibia and a secondary restraint to tibial rotation.

• approximately 95,000 ACL injuries occur each year (1 in every 3,000 people)

• isolated ACL injuries account for 50% of all ligamentous knee injuries

• 70% of injuries occur during a sporting activity

INCIDENCE OF ACL INJURIES

MECHANISM OF ACL INJURY

Noncontact Injuries• account for 60-70% of ACL

injuries• most noncontact injuries

occur at footstrike with the knee close to full extension

• result from sudden deceleration prior to change of direction or awkward landing position

Contact Injuries• account for 30-40% of ACL

injuries• occur as a result of valgus

collapse of the knee

• Anatomic Factors• Neuromuscular Factors• Gender• History of Previous Injury• Genetic Factors• Type of Sport• Extrinsic Factors

RISK FACTORS FOR ACL INJURY


Anatomic Factors• Knee Geometry

– intercondylar notch width– posterior tibial slope– decreased medial tibial plateau depth of

concavity• ACL Volume• Anterior-Posterior Laxity• Generalized Joint Laxity• Static Alignment of the Lower

Extremity– valgus knee alignment

• Body Mass Index– higher BMI in female athletes


History of Previous Injury• ACL injury < 12 months –

11.3 times more likely to injure graft or contralateral ACL

• ACL injury > 12 months – 4.4 times more likely to injure graft or contralateral ACL

Neuromuscular Factors• Posture and Landing Biomechanics• Core Stability

– the body’s capacity to maintain or resume a relative position after perturbation


Gender• ACL injuries are 3.5 times

greater in basketball and 2.67 times greater in soccer for female athletes

• Reasons:– anatomic differences– neuromuscular control

• female athletes land from jumps and perform agilities with less hip and knee flexion, increased knee valgus, increased internal rotation of the hip and external rotation of the tibia, and increased quadriceps activation

– sex hormones

Genetic Factors• Higher incidence of ACL injury in

the immediate family of injured athlete (35%) vs. the immediate family of uninjured athlete (4%)

• COL1A1, COL5A1, and COL12A1 genes



Type of Sport• Female soccer – 1 in 6,500

exposures (19%)• Football – 1 in 9,800

exposures (41%)• Female basketball – 1 in

11,000 exposures (13%)


Extrinsic Factors • Cleat Design

– Edge design – longer, irregular cleats placed at the peripheral margin of the forefoot with smaller pointed cleats placed interiorly

– Flat design – cleats on the forefoot are the same height, shape, and diameter

– Screw-in design– Pivot disk design – 10 cm circular

edge on forefoot with central cleat• Athletes wearing edge design cleats

are 3.5 times more likely to sustain ACL injury secondary to higher levels of torsional resistance between the foot and the ground


Extrinsic Factors• Playing Conditions and

Surfaces– dry surfaces > wet surfaces– artificial surfaces > natural

surfaces• artificial turf vs. natural grass

(1.5 x)• indoor synthetic floor vs.

wooden floor (2.35x)– hot weather > cool weather

TREATMENT AND REHABILITATION

PREVENTION OF ACL INJURYIdentification of “At Risk” Athletes• female soccer and basketball

athletes• football players• athletes with history of previous

ACL injury• multivariable model of analysis

PREVENTION OF ACL INJURY

Conditioning and Strength Training• Goal:

– establish and maintain appropriate hamstrings to quadriceps strength relationship


Prophylactic Bracing• Controversial• Largest study involved 1396 cadets

and 16 ACL injuries occurred – 4 in the braced group and 12 in the non-braced group.

• Study determined that bracing did not significantly decrease the SEVERITY of ACL and MCL injuries.

• Human biomechanical studies have demonstrated that bracing significantly reduces ACL strain values for anterior-directed shear loading in the weight bearing and nonweight bearing knee and internal rotation torque in the nonweight bearing knee.


Prophylactic Bracing• Proper fit is a critical

factor• Most athletes will

require custom fitted braces secondary to thigh:calf ratio difference

• The athlete should feel proper counter pressure at the proximal tibial strap from 20° to full extension


Playing Surfaces• appropriately irrigated and

maintained practice and competition surfaces

Types of Cleats• non-edge design cleats


Specific Training Protocols• Balance Training

– series of exercises that involve having the athlete attempt to maintain a balanced position while on a single leg

– results are mixed• Plyometric/Agility Training

– Santa Monica ACL Prevention Project or PEP (Prevent Injury, Enhance Performance) Program

PREVENTION OF ACL INJURYSanta Monica ACL Prevention Project• Goals:

– avoiding vulnerable positions– increasing flexibility– increasing strength– including plyometric exercises in training program– increasing proprioception through agilities

• Program should be completed a minimum of 2-3 times per week as a warm-up prior to athletics

• Results: – athletes that did not perform the program had a 3.3 times greater injury rate– 88% decreased incidence of injury (32 injuries in untrained group vs. 2

injuries in trained group)

http://assets.ngin.com/attachments/document/0004/0565/The_Santa_Monica_ACL_Injury_Prevention_Project.pdf

SANTA MONICA ACL PREVENTION PROJECT LINK





SUMMARY

• ACL injuries are extremely common and debilitating for the competitive athlete.

• There are multiple risk factors that must be considered and modified when possible.

• ACL prevention involves identification of those athletes most at risk, employment of proper strength and conditioning, use of proper equipment, and initiation of a PEP Program or similar protocol.

Go EAGLES

THANK YOU

2 nd Annual Sports Medicine Conference Don G. Aaron, Jr., MD June 8, 2013

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Transcript of 2 nd Annual Sports Medicine Conference Don G. Aaron, Jr., MD June 8, 2013