1. Prevention and Rehabilitation for ACL injuries

2. Objectives Brief understanding of prevalence and risks of ACL injuries
Understand knee mechanics and importance in protecting the ACL
Familiar with the components of ACL prevention program

3. What is the ACL anyway? ACL – anterior cruciate ligament
1 of 4 ligaments in the knee joint
Provide stability by limiting the tibia (lower leg bone) from moving forward in relation to the femur (upper leg bone)
Limits rotation of the knee joint

4. ACL injuries/tears Contact vs. non-contact
~80% non-contact (soccer, basketball, skiing, etc.)
~20% contact (football, ice hockey)
Non-contact – usually with landing, rapidly stopping, cutting or change in direction
Altered biomechanical and neuromuscular patterns
Female athletes have 3.5 x risk of non-contact injury compared to males

5. Figure 1b. Pivot shift injury.
Figure 1b. Pivot shift injury. (a) Drawing shows a skier with a right knee pivot shift injury (knee valgus, femur internally rotated), a noncontact injury that results when decelerational-rotational-valgus stress is applied to the knee while it is in various states of flexion. (b) Drawing shows that, with the foot planted, the combination of valgus stress on the knee and internal rotation of the femur results in disruption of the ACL. After disruption of the ACL, the tibia is free to sublux anteriorly relative to the femur. This movement results in the impaction of the lateral femoral condyle against the posterolateral tibial plateau. Crosshatching indicates areas of bone contusion. The degree of flexion of the knee at injury determines the exact location of the lateral femoral condyle contusion.
Sanders T G et al. Radiographics 2000;20:S135-S151
©2000 by Radiological Society of North America

6. Prevalence of ACL injury
Roughly 250,000 ACL Tears per year in the U.S.
$20,000+ per reconstruction + rehabilitation
$5 billion annual cost
6-12 months away from sport
High rate of re-injury upon return

7. Bracing
Following ACL repair and appropriate rehab – generally not used during sport
no scientific evidence that a brace is needed after successful reconstruction and rehab.1
May use if have ACL tear without surgical intervention
Bracing supports the muscles and ligaments at the knee region – typically with rehab and sport specific exercises the brace will not be needed and may actually cause the knee to become weaker as the body relies on the brace. Bracing needs to be used until athletes achieve optimal outcomes (good strength, stability, etc).

8. ACL Injury Prevention Program: Basic Components
Warm–Up (~2 min): increase core temp, increase heart rate, and circulation throughout the musculature
Stretching (~2 min): either dynamic (stretching while moving) or static (stationary/traditional stretching)
Strengthening (~4min): focus on the hip region and the thigh regions
Plyometrics (~4 min): jumping, landing, ballistic movements
Agility (~4 min): cutting, changing directions

9. ACL Prevention Program
Goal: decrease the number of ACL tears
Improve neuromuscular control and train proper movement patterns
Gain biomechanical efficiency and accuracy of movement
Enhance dynamic strength and muscle endurance of the trunk, hip and knee
15-minute training session that replaces the traditional warm-up of practice
Education for players on strategies to avoid injury
completed PRIOR TO and DURING sport season
At least 2-3 times per week x 15 min each session
Most important factor – strengthening, pre-season training and between seasons continue strengthening for sport specific activities.
Each sport can be broken down into basic fundamental movements. The art of designing a prevention program is identifying movement patterns unique for a given sport.

10. Jumping Technique Land: on the balls of the feet
knees flexed (initially ~ 20 deg and then bend to about 40 deg) - Simple cue to land “softly” has been shown to decrease force at the ACL 3
chest over the knees
avoid excessive movement of the knee upon landing (inward or forward) – keep knee over the middle of the foot
Keep hips straight – don’t turn out hips
Equal weight on the right and left
Excessive motion of the knee in an inward motion is valgus – this may be used during demonstration of exercises.
Form during squatting exercises should be similar – avoiding excessive motion of the knee, keeping knee over middle of the foot, keeping hips straight, equal weight.

11. Jumping Technique
Jumping technique – watch for knees coming together during the first jump

12. Basketball injury Rebecca Lobo basketball injury
Watch during landing on the left foot – knee falls inward

13. Knee alignment
Note on the good side – knees over the middle toe region (not fallen inward) , equal weight on both sides

14. Why land with knee bent?
Quad muscles works to extend the knee region – also pulls the lower leg bone forward (tibia) relative to the upper leg bone (femur)
ACL prevents this forward movement of the tibia
Hamstring muscles work to bend the knee and pull the tibia backward (works with the ACL)
Hamstring allows the muscles to absorb the force when landing and supports the ACL
Landing with knee bend causes less stress at the ACL and allow muscles to absorb the force
Femur
femur

15. Strengthening Component
Balance between the hamstring and quad muscles
recommended that the hamstrings be % as strong as the quads
Work on the hip muscles to stabilize knee and control knee

16. Plyometrics
Designed to produce fast, powerful movements, and improve the functions of the nervous system
Examples: squat jumps, drop jumps, bounding
Has been shown to be one of the most effective tools to reduce non-contact ACL injuries 4

17. Agility Cutting, changing directions, changing speed of movement
Tips for safe agility training:
Keep body moving in direction you are going
Keep center of mass over your feet
Don’t overcut
Careful of knee position

18. What does research say
Lim et al. “injury prevention program could potentially modify the flexibility, strength and biomechanical properties associated with ACL injury and lower the athletes risk for injury”
Female basketball student who had injury prevention 20 min warm up every practice demo increased strength and flexibility
Gilchrist et al. studied just under 1500 collegiate athletes:
70% reduction in ACL injury with noncontact injury
40% overall reduction in ACL injury
Gilchrist: randomized control trial: intervention and control group – neuromuscular training 3 x per week

19. References
Dubljanin-Raspopovic E, Bumbasirevic M, Devecerski G, Matanovic D. The effects of functional knee bracing after anterior cruciate ligament reconstruction. Med Pregl Sep-Oct;62(9-10):483-7.
Bien DP. Rationale and implementation of anterior cruciate ligament injury prevention warm-up programs in female athletes. J Strength Cond Res Jan;25(1):
Laughlin WA, Weinhand JT, Kernozek TW, Cobb SC, Keenan KG, O’Connor KM. The effects of single-leg landing technique on ACL loading. J Biomech. 2011Jul7:44(10): Epub 2011 May 10
Lim BO, Lee YS, Kim JG, An KO, Yoo J, Kwon YH. Effects of sports injury prevention training on the biomechanical risk factors of anterior cruciate ligament injury in high school female basketball players. Am J Sports Med Sep;37(9): Epub 2009 Jun
Gilchrist J, Mandelbaum BR, Melancon H, Ryan GW, Silvers HJ, Griffin LY, Watanabe DS, Dick RW, Dvorak J. A randomized controlled trial to prevent noncontact anterior cruciate ligament injury in female collegiate soccer players. Am J Sports Med Aug;36(8):
Willy RW, Davis IS. The Effect of a Hip Strengthening Program on Mechanics During Running and During a Single Leg Squat J Orthop Sports Phys Ther Jul 12. [Epub ahead of print]
Lubahn AJ, Kernozek TW, Tyson TL, Merkitch KW, Reutemann P. Chestnut JM.Hip muscle activation and knee frontal plane motion during weight bearing therapeutic exercises. Int J Sports Phys Ther Jun;6(2):
R Tyler Hamilton, MS, ATC, Sandra J Shultz, PhD, ATC, CSCS, Randy J Schmitz, PhD, ATC, and David H Perrin, PhD, ATC, FACSM. Triple-Hop Distance as a Valid Predictor of Lower Limb Strength and Power. J Athl Train Mar-Apr; 43(2): 144–151.