acl injuries in female athletes: theoretical causes and ... · acl injuries in female athletes:...
TRANSCRIPT
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Michelle Barber Drover, MSW, DCAssociate Dean, Palmer College of Chiropractic
ACL Injuries in Female Athletes:Theoretical Causes and
Prevention
Image from pxhere.com
ACL: Anterior Cruciate Ligament
Primary stabilizer of the knee
Limits rotation and anterior translation of the tibia
Protects the menisci from shearing forces
2Image from www.southcountypt.com
Length• 22-41mm• Avg 32mm
Width• 7-12mm
Cross-sectional diameter• 36-49mm2
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Image from www.louisville.edu
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“No person in the United States shall, on the basis of sex, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any education program or activity receiving Federal financial assistance...”
- Title IX of the Educational Assistance Act (1972)
Image from www.womenssportsfoundation.org
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Image from www.womenssportsfoundation.org
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Early opponents of Title IX legislation were concerned that women were
weaker and would have significantly injury rates than men, and
therefore should not be allowed to compete.
This fear was largely unfounded…with one glaring exception.
ACL Injuries/Tears
Non-Contact – usually with landing, rapidly stopping, cutting or change in direction
Altered biomechanical and neuromuscular patterns
Contact vs. Non-Contact
20% contact (football, rugby, ice hockey)
80% non-contact(soccer, basketball, skiing, etc.)
>70% of ACL injuries are sports-related
Often associated with concurrent meniscal injury
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ACL Injury Mechanisms
Hip internally rotated, adducted
Knee near full extension
Tibia externally (or internally) rotated
Foot everted and planted
Body decelerating
Combo of above leads to “Dynamic Knee Valgus” (collapse of the knee)
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8Image from www.physio-pedia.com, adapted from work of Dr. Mary Ireland
Prevention of ACL Injuries
100,000 ACL tears every year
Majority in 15 to 25 year olds
Cost to society 1.5 Billion dollars a year
Short term, loss of participation and game time
Long term, higher chance of arthritis in future
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ACL Injury: The Gender Gap
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• Females
– 4-8x more likely to tear the ACL than males in similar sports
– More likely to have surgery for an ACL injury
– Less likely to return to sports after ACL injury
– 40,000 ACL tears in females/yr
Image from www.daytondailynews.com
Image from contemporarypediatrics.modernmedicine.com 11
Impact of an ACL Injury
• Surgery and/or 6-9 months of rehabilitation
Physical
• Athletes miss whole seasons of play, possible loss of scholarship
• Often limits future sports participation
• Negative impact on academic performance
Social/Academic
• Treatment is $17,000 - $25,000 per injury ($800 million/yr)
Financial
• Despite treatment, 10x rate of early-onset knee OA (15-20 years post injury)
Long-term health
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Factors in Female ACL Injury Risk
Intrinsic (unchangeable)
Extrinsic (changeable)
Combined (potential change)
Joint Laxity Type of Sport Proprioception
Hormonal InfluencesEnvironmental
ConditionsNeuromuscular
Control
Femoral Notch Size ConditioningMuscle Recruitment
Patterns
Ligament Size Strength Core Stability
Limb Alignment Shoes
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Balance of Power• Recruitment Pattern
• Quadriceps muscles antagonist
– stress ACL
• Hamstring muscles agonist
– protect ACL
• Weak hamstrings and strong quadriceps puts ACL at risk
– Female Quad dominant
– Male Hamstring dominant
• Hamstrings 60% to 80% as strong as Quadriceps
Anatomic Factors
Intercondylar Notch
Small notch
Small Ligament size
Intercondylar notch
ACL
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Pantano et al noted that pelvic width to femoral length measurements may be a more accurate structural predictor of
knee valgus and subsequent ACL tension during dynamic activities.
Larger Q-angle tends to place the lower leg into a valgus position resulting in a possible strain on the ACL.
females demonstrate a wider pelvis and a greater average Q-angle.
Q-angle and pelvic width to femoral length ratio
Anatomic Factors: Limb Alignment
Anatomic Factors: Limb Alignment
Environmental Factors
• Fields
• Cleat Design
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Hormonal Factors
• Estrogen and Relaxin
• Relax and soft tissues
• Does this predispose female athlete to ACL injury?
– Increased incidence of ACL tears during ovulatory phase?
Hormonal Factors
Estrogen
• receptors located on the ACL
• reduction of collagen synthesis and fibroblast production
Estradiol and Progesterone
• associated with increased knee and ankle laxity
ACL Injuries Prevention
Biomechanical Factors critical
Neuromuscular/Proprioceptive programs
Plyometric/jump training and Balance drills
Retrain mind on body position
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Prevention Strategies
Greatest success if follow 3 principles:
Plyometrics, balance and strengthening, core
stability, biomechanical feedback
>1x/week Minimum of 6 weeks
Neuromuscular training programs have been shown to decrease ACL injury rates
72% 89% 88% 74% 75%
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ACL Injury Prevention Program: Basic Components
• increase core temp, increase heart rate, and circulation throughout the musculature
Warm–Up (~2 min)
• either dynamic or static Stretching (~2 min)
• focus on the core, hip and thigh regionsStrengthening
(~4min):
• jumping, landing, ballistic movements Plyometrics
(~4 min):
• cutting, changing directions Agility
(~4 min):
ACL Prevention Program
• 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
Goal: the number of ACL tears
• At least 2-3 times per week x 15 min each session
• Replaces the traditional warm-up of practice
• Education for players on strategies to avoid injury
Completed PRIOR TO and DURING sport season
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25Image from orthopropt.com
MANY ACL Prevention Programs out there…
www.smsmf.org/smsf-programs/pep-program
www.aclprevent.com
www.sportsmetrics.net
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References• American Orthopedic Society for Sports Medicine. Hewett TE, Shultz SJ, Griffin LY, Eds. Understanding and Preventing
Noncontact ACL Injuries. Human Kinetics, 2007.
• Beynnon BD, Bernstein IM, Belisle A, et al. The effect of estradiol and progesterone on knee and ankle joint laxity. American Journal of Sports Medicine. 2005 Sep; 33(9): 1298-304.
• Bonci CM. Assessment and Evaluation of Predisposing Factors to Anterior Cruciate Ligament Injury. J Athl Train 1999;34(2):155-164.
• Bosco C, Tarkku L, Komi PV. Effect of elastic energy and myoelectric potentiation of triceps surae during stretch-shortening cycle exercise. Int J Sports Med 1982;3(3):137-140.
• Chandrashekar N, Slauterbeck J, Hashemi J. Sex-based differences in the anthropometric characteristics of the anterior cruciate ligament and its relation to intercondylar notch geometry: a cadaveric study. American Journal of Sports Medicine. 2005 Oct; 33 (10):1492-8.
• Chappell JD, Creighton RA, Giuliani C, Yu B, Garrett WE. Kinematics and electromyography of landing preparation in vertical stop-jump: risks for noncontact anterior cruciate ligament injury. Am J Sports Med 2007;35(2):235-241.
• Dienst M, Schneider G, Altmeyer K, Voelkering K, Georg T, Kramann B, Kohn D. Correltation of intercondylar notch cross sections to the ACL size: a high resolution MR tomographic in vivo analysis. Arch Orthop Trauma Surg 2007;127(4):253-260.
• Draganich LF, Vahey JW. An in vitro study of anterior cruciate ligament strain induced by quadriceps and hamstring forces. Journal of Orthopedic Res. 1990; 8(1):57-63.
• Ford KR, Myer GD, Toms HE, Hewett TE. Gender differences in the kinematics of unanticipated cutting in young athletes. Medicine and Science in Sports and Exercise. 2005 Jan; 37(1):124-9.
• Grindstaff TL, Hammill RR, Tuzson AE, Hertel J. Neuromuscular control training programs and noncontact anterior cruciate ligament injury rates in female athletes: a numbers-needed-to-treat analysis. J Athl Train 2006;41(4):450-456.
• Harmon KG, Ireland ML. Gender differences in noncontact anterior cruciate ligament injuries. Clin Sports Med 2000;19(2):287-302.
• Hewett TE, Lindenfeld TN, Riccobene JV, Noyes FR. The effect of neuromuscular training on the incidence of knee injury in female athletes: a prospective study. Am J Sports Med 1999;27(6):699-706.
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References• Hewett TC, Schultz SJ, Griffin LY. Understanding and Preventing Noncontact ACL Injuries. American
Orthopedic Society for Sports Medicine. Human Kinetics. 2007.• Hewett TE, Stroupe AL, Nance TA, Noyes FR. Plyometric training in female athletes: decreased impact
forces and increased hamstring torque. Am J Sports Med 1996;24(6):765-773.• Ireland ML. The female ACL: why is it more prone to injury? Orthop Clin North Am 2002;33(4):637-651. • Ireland ML. Anterior Cruciate Ligament Injury in Female Athletes: Epidemiology. J Athl Train
1999;34(2):150-154. • Ireland ML, Ott SM. Special concerns of the female athlete. Clin Sports Med 2004;23(2):281-298. • Leetun DT, Ireland ML, Willson JD, Ballantyne BT, Davis IM. Core stability measures as risk factors for
lower extremity injury in athletes. Med Sci Sports Exerc 2004;36(6):926-934. • Liu SH, Al-Shaikh RA, Panossian V, et al. Estrogen affects the cellular metabolism of the anterior cruciate
ligament: a potential explanation for female athletic injury. Am J Sports Med, 1997; 25(5): 704-09.• Mandelbaum BR, Silvers HJ, Watanabe DS, Knarr JF, Thomas SD, Griffin LY, Kirkendall DT, Garrett W Jr.
Effectiveness of a neuromuscular and proprioceptive training program in preventing anterior cruciate ligament injuries in female athletes: 2-year follow-up. Am J Sports Med 2005;33(7):1003-1010.
• McClay, I. ACL research retreat: the gender bias, April 6-7, 2001. Clin Biomech (Bristol, Avon) 2001;16(10):937-959.
• McGill, S. Ultimate Back Fitness and Performance. Stuart McGill, 2004.• Myer GD, Ford KR, Hewett TE. Rationale and Clinical Techniques for Anterior Cruciate Ligament Injury
Prevention Among Female Athletes. J Athl Train 2004;39(4):352-364. • Myklebust G, Engebretsen L, Braekken IH, Skjolberg A, Olsen OE, Bahr R. Prevention of anterior cruciate
ligament injuries in female team handball players: a prospective intervention study over three seasons. Clin J Sport Med 2003;13(2):71-78.
• Sigward SM, Powers CM. The influence of gender on knee kinematics, kinetics and muscle activation patterns during side-step cutting. Clin Biomech (Bristol, Avon) 2006;21(1):41-48.
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