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

ACL INJURY PREVENTION I.ACL Anatomy and Function II.Incidence of ACL Injuries III.Mechanism of Injury IV.Risk Factors for Injury V.Treatment and Rehabilitation VI.Prevention of Injury VII.Summary

ACL ANATOMY AND FUNCTION Anatomy 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

RISK FACTORS FOR ACL INJURY 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

RISK FACTORS FOR ACL INJURY 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 RISK FACTORS FOR ACL INJURY

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%)

RISK FACTORS FOR ACL INJURY 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

RISK FACTORS FOR ACL INJURY 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 INJURY Identification 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

PREVENTION OF ACL INJURY 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.

PREVENTION OF ACL INJURY 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

PREVENTION OF ACL INJURY Playing Surfaces appropriately irrigated and maintained practice and competition surfaces Types of Cleats non-edge design cleats

PREVENTION OF ACL INJURY 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 INJURY Santa 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)

PREVENTION OF ACL INJURY

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

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