Over 250,000 anterior cruciate ligament (ACL) injuries occur in young, active individuals each year in the United States. 1,2 Highest- risk populations include athletes participating in pivoting and cutting sports, adolescent athletes, and female atheltes.3 ACL reconstruction (ACLR) is the standard treatment of choice, with approximately 90% of patients going on to surgery. 3 The goal of surgery is to restore appropriate knee joint function and functional stability, in order to allow for return to pre-injury activity. 4 However, even after a rigorous rehabilitation program, incidence of secondary ACL injury (same leg or opposite leg) have been reported to range form 6% 5,6 to 29.5% 7 within 24 months of the time to return to sport.
However, even after a rigorous rehabilitation program, incidence of secondary ACL injury (same leg or opposite leg) have been reported to range form 6% 5,6 to 29.5% 7 within 24 months of the time to return to sport.
As both a strength coach and rehabilitation practitioner I have seen numerous athletes that were returned to sport before they were truly ready. The current outcome measures that are evaluated for return to sport criteria do not take into account the overall quality and compensatory movements that are seen in ACLR patients. Recent studies have shown that neuromuscular and biomechanical patterns lead to poor movement quality that can last for up to 2 years following ACLR7, 8 and have been found to lead to reinjures. Normal strength recovery after ACLR does not translate to the appropriate neuromuscular control needed for athletic endeavors.9, 10 Proper neuromuscular control is achieved by the balance of adequate strength, mobility, kinesthetic awareness (awareness of position in space), joint mechanics, and adaptive motor control strategies. 9
The current outcome measures that are evaluated for return to sport criteria do not take into account the overall quality and compensatory movements that are seen in ACLR patients.
Even after athletes are cleared to return to sport, deficits in neuromuscular control are evident. 9,10,11,12. These deficits have been shown to be highly predictive of the risk of secondary injury.11 Four predictive biomechanical factors have been identified: (1) inward rotation of the uninvolved limb at landing, (2) increased inward and outward horizontal motion of the knee during landing, (3) landing with decreased knee flexion, (4) and increased trunk motion. 11 These four factors have been shown to predict a second ACL injury 88% of the time when present.11
Even after athletes are cleared to return to sport, deficits in neuromuscular control are evident.
Neuromuscular training programs have been shown to reduce primary ACL injury 43.8% to 73.4%. 13 However such programs have not been examined for reducing the risk for secondary injuries, 9 the four predictive factors can be trained and improved. Components of a successful neuromuscular training program include training: technique, landing, plyometric, trunk stability, balance/proprioceptive, and last but not least strength. Given that all athletes are different and every athlete presents with different needs, training should be tailored to address the deficits identified in each athlete. 9
Even though most strength training programs include these multiple components, it takes a true professional to determine deficits that are present, develop correct programing, implement proper motor learning strategies, and watch for compensatory movements. Initial ACL injuries are devastating injuries that can be a speed bump and end an athletic season, while secondary ACL injuries are sometimes end careers and have a high psychological toll on an athlete. Given that secondary ACL injuries can be reduced by almost 90% 11 with proper assessment and treatment of neuromuscular deficits we can keep these athletes on the field playing the sports they love. In short, proper training is the same as injury prevention, only when the mechanisms of injury are known and deficits trained.
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Marshall SW, Padua D, McGrath M. Incidence of ACL injury. Inc Hewett TE, Shultz SJ, Griffin Ly, eds. Understanding and Preventing Noncontact ACL Injuires. Champaign. Illinois: Human Kinetics: 2007:5-30
Lyman S, Koulouvaris P, Sherman S, Do H, Mandl LA, Mark RG. Epidemiology Of Anterior Cruciate Ligament Reconstruction. Trends, Readmissions, and Subsequent Knee Surgery. . J Bone Joint Surg Am. 2009; 91:2321-2328
Paterno MV, Rauh MJ, Schmitt LC, Ford KR, Hewett TE. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport. AM J Sports Med. 2014
Salmon L, Russell V, Musgrove T, Pinczewski L, Refshauge K. Incidence and risk factors for graft rupture and contralateral rupture after anterior cruciate ligament reconstruction. Arthroscopy. 2005; 21(8): 948-957.
Wright RW, Dunn WR, Amendola A, et al. Risk of tearing the intact anterior cruciate ligament in the contralateral knee and rupturing the anterior cruciate ligament graft during the first 2 years after anterior cruciate ligament reconstruction: a prospective MOON cohort study. Am J Sports Med. 2007;35(7):1131-1134.
Paterno MV, Ford KR, Myer GD, Heyl R, Hewett TE. Limb asymmetries in landing and jumping 2 years following anterior cruciate ligament reconstruction. Clin J Sport Med. 2007;17(4):258-262.
Roewer BD, Di Stasi SL, Snyder-Mackler L. Quadriceps strength and weight acceptance strategies continue to improve two years after anterior cruciate ligament reconstruction. J Biomech. 2011; 44(10): 1948-1953.
Di Stasi SL, Myer GD, Hewett TE. Neuromuscular Training to Target Deficits Associated With Second Anterior Cruciate Ligament Injury. J Orthop Sports Phys Ther. 2013; 43(11): 777-792
Di Stasi SL, Logerstedt D, Gardinier ES, Snyder-Mackler L. Gait pattern differ between ACL-reconstruction athletes who pass return-to-sport criteria and those who fail. AM J Sports Med. 2013; 41:1310-1318
Paterno MV, Schmitt LC, Ford KR, et al. Biomechanical measures during landing and postural stability predict second anterior cruciate ligament reconstruction and return to sport. Am J Sports Med. 2010; 38 1968-1978
Di Stasi SL, Snyder-Mackler L. The effects of neuromuscular training on the gait patterns of ACL-deficient men and women. Clin Biomech (Bristol, Avon). 2012; 27:360-365
Sugimoto D, Myer GD, McKeon JM, Hewett TE. Evaluation of the effectiveness of neuromuscular training to reduce anterior cruciate ligament injury female athletes: a critical review of relative risk reduction and number-needed-to-treat analyses. Br J Sports Med. 2012; 46:976-988