1. ACL Prevention Amanda KW Kelly, MD Case Western Reserve University
Rainbow Babies and Children’s Hospital

2. Outline
Background
Injury risk factors
ACL prevention programs

3. Background 250,000 ACL injuries/yr in USA
$1.5 billion annual cost
% return to previous level of play
Typical recovery 6-9 mo
> 70% ACL injuries are NON-contact
Boden 2000 Physspportsmed

4. Importance of ACL Injury
Season ending injury
6-9 mo recovery time
Children often must wait several yrs for repair
Costly

5. ACL Anatomy
PCL
ACL
LCL
MCL

6. ACL: Function
Keep tibia from sliding forward on the femur

7. Injury Mechanisms Pivot Landing from jump Contact

8. 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

9. Mechanism: Pivot
Importance of ground-shoe surface interface in pivot mechanism
Shoe surface interface

10. Mechanism: landing Knee slightly flexed on landing
Quad pulls tibia forward

11. Mechanism: Contact
Hit on outside of leg
Foot planted
Twisting of knee

12. 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

13. Risk Factors Poor landing + pivot style Stronger quads than hamstrings
Shoe / playing surface interface
Playing surface quality
Female gender

14. Risk Factors Landing / Pivoting with knee slightly bent
Places ACL in vulnerable position
Additional torsion/twisting can  injury
Boden 2000 Physsportsmed

15. 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

16. 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

17. Risk Factor Uneven playing surface
Unexpected foot position may change muscle activation patterns
Balance thrown off
Boden, Orthopedics

18. 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

19. 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

20. Female Gender Knee anatomy Smaller intercondylar notch
ACL may get stretched across bone and torn
Athletes with bilateral ACL injuries have smaller ICN
Harner 1994 AJSM, Anderson 1999 AOSSM

21. Female Gender Lower extremity alignment Women more knock-kneed
May allow quad to exert more stress on ACL
Data not great
Nisell 1985 ActaOrthopScandSuppl

22. Prevention Strategies
Shoe wear / field surface
Bracing
Exercise Programs
Change muscle strength + activation
Change landing / Pivoting patterns
Sportmetrics
PEP

23. 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

24. Prevention
Improve playing field????

25. 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

26. 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

27. 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

28. 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

29. 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

30. Training Programs Sportmetrics PEP 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

31. PEP Program Designed to replace usual warm-up Warm-up Stretch correct
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

32. PEP Program Strength Walking lunges 20yd x 2 Russian hamstr 30s
Single toe raise 30x
Mandelbaum 2005 AJSM

33. PEP Program Plyometrics Lateral hops 30s Forward hops 30s
Single leg hops 30s
Vertical jumps 30s
Scissor jumps 30s
Mandelbaum 2005 AJSM

34. PEP Program Agilities Knees bent incorrect correct Shuttle run 40yd
Diagonal run 40yd
Bounding run 50yd
Knees bent
Avoid upright position
incorrect
correct
Mandelbaum 2005 AJSM

35. Sportsmetrics Warm-up: Stretching: 3 sets, 30s each Skipping: 2 laps
Calf, quad, hamstring, hip flexor, IT Band, low back, posterior deltoids, latissimus, pects/biceps
Skipping: 2 laps
Side shuffle: 2 laps

36. Sportsmetrics Phase I: Technique Week 1 Week 2 Wall jumps Tuck jumps
Broad jumps: hold landing
Squat jumps
Double-leg cone jumps
180 jumps
Bounding in place
20s
5 reps
10s
30s/30s
25s
10 reps
15 s
(Side-side/front-back)
Hewett 1999 AJSM

37. Sportsmetrics Phase II Week 3 Week 4 Wall jumps Tuck jumps
Jump, jump, jump, vertical jump
Squat jumps
Bounding for distance
Double-leg cone jumps
Scissors jump
Hop, hop hold landing
30s
5 reps
20s
1 run
30s/30s
5 rep/leg
8 reps
2 runs
4 rep/leg
Hewett 1999 AJSM

38. Sportsmetrics Phase III Week 5 Week 6 Wall jumps
Step, jump up, down, vertical
Mattress jumps (Side-side/front-back)
Single-leg jumps distance
Squat jumps
Jump into bounding
Hop, hop, hold landing
30s
5 reps
30s/30s
5 reps/leg
25s
3 runs
10 reps
4 runs
Hewett 1999 AJSM

39. 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

40. 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

41. 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

42. 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

43. Goals
Emphasize proper landing technique
RIGHT
WRONG

44. Proper landing Before Training After training
Barber-Westin, 2006, AJSM; Noyes 2005 AJSM

45. Decreased Injury ’d non-contact injuries in trained groups
0.47
UT: Untrained
T: Trained
MC: Male Control
0.35
0.09
0.05
PEP
Mandelbaum 2005 AJSM
Sportsmetrics
Hewett 1999 AJSM

46. 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 Witzke MSSE 2000, Hewett 1999 AJSM

47. 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

48. 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 (6)
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

49. 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)
Noyes et al. The Drop-Jump Screening Test. Amer J Sports Med. 2005: 33(2)