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ACL Prevention. Amanda KW Kelly, MD Case Western Reserve University Rainbow Babies and Children’s Hospital. Outline. Background Injury risk factors ACL prevention programs. Background. 250,000 ACL injuries/yr in USA $1.5 billion annual cost 80 - 90% return to previous level of play
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ACL Prevention Amanda KW Kelly, MD Case Western Reserve University Rainbow Babies and Children’s Hospital
Outline • Background • Injury risk factors • ACL prevention programs
Background • 250,000 ACL injuries/yr in USA • $1.5 billion annual cost • 80 - 90% return to previous level of play • Typical recovery 6-9 mo • > 70% ACL injuries are NON-contact Boden 2000 Physspportsmed
Importance of ACL Injury • Season ending injury • 6-9 mo recovery time • Children often must wait several yrs for repair • Costly
ACL Anatomy PCL ACL LCL MCL
ACL: Function • Keep tibia from sliding forward on the femur
Injury Mechanisms • Pivot • Landing from jump • Contact http://sportzfun.com/v-web/gallery/slideshow.php?set_albumName=soccer
Injury Mechanism: Pivot • Deceleration + change of direction, foot planted • Causes twisting injury of knee • Traction at shoe/playing surface interface • Often close to another player ACL
Mechanism: Pivot • Importance of ground-shoe surface interface in pivot mechanism Shoe surface interface
Mechanism: landing • Knee slightly flexed on landing • Quad pulls tibia forward
Mechanism: Contact • Hit on outside of leg • Foot planted • Twisting of knee
Mechanism • Pivoting with knee slightly bent, twisting knee • Landing from jump: knees slightly bent, quads pull tibia forward • Too much shoe traction • Poor balance • Uneven ground throwing off balance
Risk Factors • Poor landing + pivot style • Stronger quads than hamstrings • Shoe / playing surface interface • Playing surface quality • Female gender
Risk Factors • Landing / Pivoting with knee slightly bent • Places ACL in vulnerable position • Additional torsion/twisting can injury Boden 2000 Physsportsmed
Risk Factors • Hamstring/Quadriceps imbalance • Poor hamstring strength • Hamstrings protect ACL • Quads stretch/stress ACL • Slow activation of hamstring muscles with pivot / landing Hewett AJSM 1999, Crosier AJSM 2002, Huston 1996 AJSM, Orchard AJSM 1997, Baratta AJSM 1988 http://www.preventaclinjury.com/knee_biomechanics.htm
Risk Factors • Footwear • Longer cleats at edge of sole with fewer, smaller cleats in the middle of the sole • ’s torsional resistance Lambson 1996 AJSM
Risk Factor • Uneven playing surface • Unexpected foot position may change muscle activation patterns • Balance thrown off Boden, Orthopedics
Risk Factors • Female Gender • 2-8x more common in girls • Poor ham:quad strength • Activate hams more slowly • Land with knees sl bent • Boys land with knees more bent
Female Gender • Hormonal Influences • ACL has estrogen receptors • Estrogen can ligament looseness • Estrogen levels in girls compared to boys • Estrogen ’d at specific times in menstrual cycle • Studies VERY inconsistent • Every phase of cycle has been implicated in at least 1 study
Female Gender • Knee anatomy • Smaller intercondylar notch • ACL may get stretched across bone and torn • Athletes with bilateral ACL injuries have smaller ICN www.hughston.com Harner 1994 AJSM, Anderson 1999 AOSSM
Female Gender • Lower extremity alignment • Women more knock-kneed • May allow quad to exert more stress on ACL • Data not great Nisell 1985 ActaOrthopScandSuppl www.hughston.com
Prevention Strategies • Shoe wear / field surface • Bracing • Exercise Programs • Change muscle strength + activation • Change landing / Pivoting patterns • Sportmetrics • PEP
Prevention: shoe wear • Shoes with lower ACL injury risk: • Cleats flat, all the same size on forefoot • Screw in cleats with 0.5in ht/diameter cleats • Pivot disk: 10-cm circular edge on sole of forefoot • Flat shoes on turf • Want balance of too much / too little traction Lambson 1996 AJSM
Prevention • Improve playing field????
Bracing • Several studies • Inconclusive results • No change in muscle activation patterns • No ACL shown in any study • Loads placed on brace during play exceeds brace • BUT, many kids who have had ACL surgery FEEL more stable in brace
Training Programs • Balance board training • Improves balance + joint position sense • Caraffa, 1996, Knee Surg Sports Traum Arthrosc • 20 min training sessions • 87% ACL injuries • 7x injury
Training Programs • Frappier Acceleration Training Program • Frappier Acceleraton, Fargo, North Dakota • Heidt, 2000, Amer Orthop Soc Sports Med • 7 wk preseason training: 3d/wk • 2d/wk treadmill sessions • 1d/wk plyometric (jump training) • ’d total # serious knee injuries • ACL ’d but not significantly
Training Programs • Sportmetrics • Hewett, 1999, Amer J Sports Med • Cinicinnati Sportsmedicine Research and Education Foundation • PEP (Prevent injury Enhance Performance) • Mandelbaum, 2005, Amer J Sports Med • Santa Monica Orthopedic and Sports Medicine Research Foundation
Program Goals • Emphasize proper jump/land techniques • Land on balls of feet • Soft landing • Toe-to-heel rocking of the foot • ground reactive forces • Knees flexed • Knees forward • Discourage inward buckling of knees (knock-kneed landing) • Chest over knees Hewett 1999 AJSM, Mandelbaum 2005 AJSM, Boden 2000 Physportsmed www.physsportsmed.com
Training Programs • Sportmetrics • 6 week Preseason-training program • 60 – 90 minute work-out • PEP • 15 minute work-out • Use in place of usual pre-practice warm-up 3 d/wk
PEP Program • Designed to replace usual warm-up • Warm-up • Jog 50yd • Shuttle run 50yd • Backward run 50yd • Stretch • Calf, quad, ham, inner thigh, hip flexor • 2 x 30s each correct incorrect Mandelbaum 2005 AJSM
PEP Program • Strength • Walking lunges 20yd x 2 • Russian hamstr 30s • Single toe raise 30x Mandelbaum 2005 AJSM
PEP Program • Plyometrics • Lateral hops 30s • Forward hops 30s • Single leg hops 30s • Vertical jumps 30s • Scissor jumps 30s Mandelbaum 2005 AJSM
PEP Program • Agilities • Shuttle run 40yd • Diagonal run 40yd • Bounding run 50yd • Knees bent • Avoid upright position incorrect correct Mandelbaum 2005 AJSM
Sportsmetrics • Warm-up: • Stretching: 3 sets, 30s each • Calf, quad, hamstring, hip flexor, IT Band, low back, posterior deltoids, latissimus, pects/biceps • Skipping: 2 laps • Side shuffle: 2 laps
Sportsmetrics (Side-side/front-back) Hewett 1999 AJSM
Sportsmetrics Hewett 1999 AJSM
Sportsmetrics Hewett 1999 AJSM
Jump Definitions • 180 jumps: 2-footed, rotate 180 in the air • Bound for distance: start bounding in place, increase distance with each step, knees high • Broad jumps-hold landing: 2-footed jump, as far as possible hold landing 5s • Cone jumps: double leg, side-side, front-back • Hop, hop, stick: single leg hop, stick landing 5s • Jump into bounding: 2-footed jump, land on 1 leg, progress into bounding for distance • Jump, jump, jump, vertical: 3 broad jumps with vertical jump after last broad jump • Mattress jumps: 2-footed jump on mattress/tramp, side-side + front-back Hewett 1999 AJSM
Jump Definitions • Scissors jump: start in stride position, one foot in front of other, jump up alternating foot position in air • Single-leg jumps, distance: single-leg hop for distance, hold landing 5s • Squat jumps: standing jump, raise arms overhead, land in squat position hands on floor • Step, jump up, down, vertical: 2-footed jump onto step, jump off with 2 feet, then vertical jump • Tuck jump: standing, bring both knees up to chest, repeat • Wall jumps: ankle bounces, arms overhead bounce up/down off of toes Hewett 1999 AJSM
Sportsmetrics • Weight-training: 12 reps upper body, 15 lower • Abdominal curl • Back hyperextension • Leg press • Calf raises • Pullover • Bench press • Lat pull downs • Forearm curl • Warm-down, stretch Hewett 1999 AJSM http://www.sportsmetrics.net/
Training Programs • Both PEP and Sportmetrics well studied • Aim: • Change landing / pivoting patterns • Flex knees more • Stop over several steps instead of sudden stop • Improve hamstring strength + activation • BOTH prevent ACL + other serious knee injury by achieving these aims
Goals • Emphasize proper landing technique RIGHT WRONG
Before Training After training Proper landing Barber-Westin, 2006, AJSM; Noyes 2005 AJSM
’d non-contact injuries in trained groups Decreased Injury 0.47 UT: Untrained T: Trained MC: Male Control 0.35 0.09 0.05 0 PEP Mandelbaum 2005 AJSM Sportsmetrics Hewett 1999 AJSM
Performance Enhancement • vertical jump • 10% jump height • strength • 44% hamstring strength • sprint speed • Improved power endurance • Improved running economy Diallo JSMPF 2001, Turner JSCR 2003, Siegler JSCR 2003, Spurs EJAP 2003, Newton MSSE 1999. Witzke MSSE 2000, Hewett 1999 AJSM
Improved Bone Density • Female athletes participating in jump training build more bone • risk for stress fracture • Prevent time lost from injury • risk for osteoporosis later in life
References • Barber-Westin SD et al. Jump-Land Characteristics and muscle strength development in young athletes. Amer J Sports Med. 2006: 34(3)1-10 • Boden BP et al. Etiology and prevention of noncontact ACL injury. PhysSportsMed. 2000: 29(4) • Caraffa A et al. Prevention of anterior cruciate ligament injuries in soccer: a prospective controlled study of proprioceptive training. KneeSurgSportsTraumatolArthrosc. 1996:4:19-36 • Heidt RS et al. Avoidance of soccer injuries with preseason conditioning. AmJSportsMed. 2000: 28(5)659-62 • Hewett TE et al. The effect of neuromuscular training on the incidence of knee injury in female athletes: a prospective study. Amer J Sports Med 1999. 27(6) 699-706 • Lambson RB et al. Football cleat design and its effect on anterior cruciate ligament injuries: a 3-yr prospective study. AmJSportsMed.1996:24(2)155-9
References • Mandelbaum BR, Silvers HJ, Watanabe DS. Effectiveness of a neuromusclular and proprioceptive training program in preventing anterior cruciate ligament injuries in female athletes: a 2-year follow-up. Amer J Sports Med. 2005: 33(7) 1003-9 • Noyes et al. The Drop-Jump Screening Test. Amer J Sports Med. 2005: 33(2)197-207