Anterior Cruciate Ligament Injuries in Women AUTHORS Barry

Anterior Cruciate Ligament Injuries in Women

AUTHORS • Barry P. Boden, MD- From the Orthopedic Center in Rockville, Maryland • Frances T. Sheehan, Ph. D- From the National Institutes of Health in Bethesda, Maryland • Joseph S. Torg MD- Temple University School of Medicine, Philadelphia, PA • Timothy E. Hewett, Ph. D- Departments of Pediatrics, Orthopedic Surgery, and Biomedical Engineering, University of Cincinnati College of Medicine, Cincinnati OH • Walter R. Shelton, MD- From Mississippi Sports Medicine and Orthopedic Center, Jackson MS. Serves as a board member of the Arthroscopy Association of North America • Bryan C. Fagan, MD- From North East Orthopedics and Sports Medicine • Robert L. Larson, MD- Clinical Professor of Surgery, School of Medicine, Oregon Health Sciences University, Portland; and is in private practice in Eugene, OR • Letha Y. Griffin, MD- Instructor in the Department of Surgery, Assistant Team Physician and member of the Sports Medicine Clinic at the University of Michigan, and also Head of Orthopaedic Surgery at Wayne County Hospital.

Objective • Explain the anatomy, biomechanics and function of the ACL • Describe the clinical signs and symptoms of an ACL injury including tests utilized to determined injury to the ACL • Discuss the anatomic risk factors, emphasizing the specific risk factors women face, including anatomical and hormonal • Describe the options of treatment selection • Explain the rehabilitation process for an ACL injury

Anatomy of the ACL • Commonly referred to as the ACL the anterior cruciate ligament is a ligament that stabilizes the knee and provides rotational stability. • The ACL is a band of dense connective tissue which runs from the femur to the tibia • ACL originates from medial and anterior aspect of the tibia plateau and runs superiorly, latterly, and posteriorly towards its insertion on the lateral femoral condyle • The ACL traditionally has been divided into anteromedial band a posterolateral band

• • Blood supply: Anatomy of ACL • Major blood supply: from middle genicular artery: • Supplied by the middle genicular artery; • Bony attachments do not provide a significant source of blood to distal or proximal ligament Discussion: • Length of 38 mm (range 25 to 41 mm) • Width of 10 mm (range 7 to 12 mm) • Made up of multiple collagen fascicles; • Surrounded by an endotendineu • Microspocially: interlacing fibrils (150 to 250 nanomet in diameter) • Grouped into fibers (1 to 20 um in diameter) • Synovial membrane envelope Wheeless, Clifford. "Wheeless' Textbook of Orthopaedics. " The Latest in Knee Arthoplasty. Duke Orthopaedics, 4 May 2012. Web. 26 Nov. 2012. <http: //www. wheelessonline. com/ortho/anatomy_of_acl>.

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Biomechanics • The ACL functions primarily to limit anterior tibial displacement • It also restraints tibial rotation and has a minor restraint to valgus and varus stress at full extension • It provides nearly 90% of anterior translation stability of the tibia

Biomechanics • Hyper-extension: - the posterolateral bundle of the ACL is tight in extension; - At 5 degrees of hyperextension, anterior cruciate ligament forces range between 50 and 240 newtons; - Hyperextension of the knee develops much higher forces in ACL than in the PCL • Flexion: • The anteromedial bundle of the ACL is tight in flexion • During isometric quadriceps contraction, ACL strain at 30 deg of knee flexion are significantly higher than at 90 deg where ligament remain unstrained with isometric quadriceps activity; • Active extension of knee between the limits of 50 and 110 degrees does not strain the anterior cruciate • At 90 degrees of flexion, the ACL accounts for approximately 85% of resistance to anterior drawing test Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print.

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Clinical Signs and Symptoms • ACL injury is often a noncontact injury occurring while changing direction or landing a jump. • Patient may feel or hear a “pop” • Swelling noted within a few hours • Knee feels unstable • Physical examination of injured knee must be compared with those of normal knee Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print. 13

• Range of motion is limited by several factors • Injection of a mixture of saline and a local anesthetic mixture may be used to provide additional relaxation and to aid in clinical examination Google Images Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print.

Clinical Tests • Lachman Test – examiner should estimate the displacement and assess the firmness of the endpoint • Pivot Shift Test – based on the fact that in early flexion there is anterior subluxation of the tibia and with further flexion the posterior pull of the iliotibial tract reduces the tibia • Anterior Drawer Test – least reliable test, may normal knees have significant excursion in this position Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print.

ACl injuries in men vs. women VS Google Images Men - Typically injure ACL during strenuous jumping maneuvers • Women - Typically injure ACL during simple decleration maneuver/noncontact activities - Core propioception deficits - Excessive lateral trunk displacement Boden, Barry, et al. "Noncontact Anterior Cruciate Ligament Injuries: Mechanisms and Risk Factors. " Journal of the American Academy of Orthopedic Surgeons 18. 9 (2010): 520 -26. Print.

• Anatomical Risk Factors in Women Knee abduction • • Females land with higher knee abduction movements Joint laxity • Women exhibit less knee stiffness making them susceptible to tears when impulsive loads are transmitted across knee joint- joints ligament dependent Google Images Boden, Barry, et al. "Noncontact Anterior Cruciate Ligament Injuries: Mechanisms and Risk Factors. " Journal of the American Academy of Orthopedic Surgeons 18. 9 (2010): 520 -26. Print.

• Knee recurvatum/hyperextension Allows knee to be closer to full extension during athletic activities • • Increased posterior tibial slope Increases risk of lateral femoral condyle sliding posteriorly on lateral tibial plateau and injuring ACL • Google Images • Boden, Barry, et al. "Noncontact Anterior Cruciate Ligament Injuries: Mechanisms and Risk Factors. " Journal of the American Academy of Orthopedic Surgeons 18. 9 (2010): 520 -26. Print.

Hormonal Risk factors in women • Estrogen and progesterone receptor sites located in ACL cells • • Female sex hormones play an active role in ACL structure • Female sex hormones influence composition and mechanical properties of ACL Studies linking hormone fluctuations during the menstrual cycle to rate of ACL injuries in women Griffin, Letha, and Randall Dick. "Noncontact Anterior Cruciate Ligament Injures: Risk Factors and Prevention Strategies. " Journal of the American Academy of Orthopedic Surgeons 8. 3 (2000): 1 -27. Print.

- More injuries expected during ovulatory phase (days 10 -14) when estrogen levels surge - Fewer injuries occurred in the follicular phase (days 1 -9) when estrogen and progesterone levels are low - Estrogen decreases ACL strength by reducing tensile properties of the ligament -Estrogen effects CNS leading to a decrease in motor skills Google Images Griffin, Letha, and Randall Dick. "Noncontact Anterior Cruciate Ligament Injures: Risk Factors and Prevention Strategies. " Journal of the American Academy of Orthopedic Surgeons 8. 3 (2000): 1 -27. Print.

Rehabilitation Phase I: Preoperative Period - Goal is to obtain full range of motion compared with normal knee - Patient is educated about details of operative procedure and postoperative rehabilitation program Phase II: 0 to 2 Weeks after Surgery - Goal is to achieve full extension, allow wound healing, maintain adequate quadriceps control, minimize swelling, and achieve flexion of 90 degrees - Full extension must be achieved early to prevent formation of scar tissue limiting movement Phase III: 3 to 5 Weeks after Surgery - Goals are to maintain full extension and increase flexion up to range of motion Phase IV: 6 Weeks after Surgery - Goal is to maintain motion and increase strength and agility Griffin, Letha, and Randall Dick. "Noncontact Anterior Cruciate Ligament Injures: Risk Factors and Prevention Strategies. " Journal of the American Academy of Orthopedic Surgeons 8. 3 (2000): 1 -27. Print.

Treatment Selection • There is no ideal method that ensures restoration of normal function • Factors to be considered: • Presence/absence of other lesions involving the knee • Age and level of activity of patient • Type of injury to ACL • Ability of patient to comply with the rehabilitation program • Type of sporting activity Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print.

• Patients with a chronic ACL deficiency must be evaluated to determine whether their instability is producing a functional disability • Also must see whether their activity level combined with instability may cause meniscal damage • In most studies, the incidence of meniscus tear in an acute ACL disruption is greater that 50% Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print.

• Non-operative Management Initial non-operative treatment of the acutely injured ACL is splinting & the use of crutches and early active range of motion • Goal: obtain full range of motion as compared to the normal knee • Strengthening is achieved by using closedchain weight-bearing exercises • Patients should receive counseling concerning high-risk activities to prevent recurrent injuries • Role of functional knee bracing remains controversial Google Images Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print.

Surgical Techniques • Appropriate surgical technique is important in ensuring proper function of reconstructed ACL • The graft must be positioned in as near an anatomic position as possible • Tunnel orientation and contour are important to avoid stress risers • Graft tensioning is important in achieving a successful ACL reconstruction Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print.

Autografts and Allografts • Autograft: A graft of tissue obtained from the patient’s own body to be used in surgical reconstruction • Allograft: A graft of tissue obtained from a donor genetically different from, though of the same species as the recipient • There are possible risks of using an allograft; there is little evidence that the long-term results are better that those associated with use of autogenous tissue Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print.

Conclusions • ACL is crucial for knee stabilization and rotational stability • Women are susceptible to ACL injuries at lower ground reaction forces than men due to differing anatomical and hormonal factors • Several factors must be taken into consideration when determining which treatment method to use • Rehabilitation follows a standard routine, but differs with each individual depending on their progress

Question for the Class • What are two anatomical risk factors women face dealing with ACL injuries?

Question for Teacher • Throughout your experience as an athletic trainer as well as working in the clinic, do you find that women are more prone to ACL injuries? If so, do the doctors address these injuries differently than they do with men?

References • Boden, Barry, et al. "Noncontact Anterior Cruciate Ligament Injuries: Mechanisms and Risk Factors. " Journal of the American Academy of Orthopedic Surgeons 18. 9 (2010): 520 -26. Print. • Griffin, Letha, and Randall Dick. "Noncontact Anterior Cruciate Ligament Injures: Risk Factors and Prevention Strategies. " Journal of the American Academy of Orthopedic Surgeons 8. 3 (2000): 1 -27. Print. • Larson, Robert. "Anterior Cruciate Ligament Insufficiency: Principles of Treatment. " Journal of the American Academy of Orthopedic Surgeons 2. 1(1994): 26 -35. Print. • Shelton, Walter. "Autografts Commonly Used in Anterior Crucial Ligament Construction. " Journal of the American Academy of Orthopedic Surgeons 19. 5 (2011): 259 -62. Print. • Wheeless, Clifford. "Wheeless' Textbook of Orthopaedics. " The Latest in Knee Arthoplasty. Duke Orthopaedics, 4 May 2012. Web. 26 Nov. 2012. <http: //www. wheelessonline. com/ortho/anatomy_of_acl. >