Clinical correlates to laboratory measures for use in non-contact anterior cruciate ligament injury risk prediction algorithm
Introduction
Female athletes are reported to be four to six times more likely than males to sustain a sports related non-contact anterior cruciate ligament (ACL) injury (Arendt and Dick, 1995, Malone et al., 1993). Several investigators have demonstrated that female athletes exhibit high knee abduction moment (KAM) related landing mechanics more often than males during landing and pivoting movements (Ford et al., 2003, Ford et al., 2006, Malinzak et al., 2001, Hewett et al., 2004, Hewett et al., 2006b, Chappell et al., 2002, Mclean et al., 2004a, Kernozek et al., 2005, Zeller et al., 2003, Pappas et al., 2007). These altered neuromuscular strategies or decreased neuromuscular control of the lower extremity during the execution of sports movements may underlie the increased risk of ACL injury in female athletes (Ford et al., 2003, Ford et al., 2005, Hewett et al., 2005, Mclean et al., 2004b, Chappell et al., 2002, Myer et al., 2006b). Females often demonstrate knee landing alignments associated with high KAM at the time of injury, in validation of these laboratory findings (Olsen et al., 2004, Krosshaug et al., 2007, Boden et al., 2000). In addition, prospective measures related to knee abduction moment measured during drop vertical jump also predict ACL injury risk in young female athletes (Hewett et al., 2005) and in military cadets (Padua et al., 2009).
Calculation of KAM, through inverse dynamics, requires complex laboratory-based three-dimensional kinematic and kinetic measurement techniques. However, a recent report has isolated biomechanical measures that contribute to nearly 80% of the measured variance in KAM during landing (Myer et al., in press-a). These biomechanical predictors of KAM, which include increased knee abduction angle, increased relative quadriceps recruitment and decreased knee flexion range of motion (RoM), concomitant with increased tibia length and mass normalized to body height that accompanies growth, are also measurements that have all been related to increased risk of ACL injury in previous prospective and retrospective epidemiological reports (Boden et al., 2000, Uhorchak et al., 2003, Hewett et al., 2005, Padua et al., 2009). Unfortunately, expensive biomechanical laboratories, with the costly and labor intensive measurement tools to test individual athletes, are required to acquire these measurements. This restricts the potential to perform athlete risk assessments on a large scale, in particular limiting the potential to target high injury risk athletes with the appropriate intervention strategies. If simpler assessment tools are developed that can be administered in a clinic or field testing environment, which are validated by the highly accurate laboratory-based assessment, screening for ACL injury risk can be performed on a more widespread basis. The purpose of the current study was to identify potential correlates to laboratory-based predictors of high KAM for use in clinic-based ACL injury risk prediction algorithm. The hypothesis tested was that clinically obtainable correlates to measures used in the highly predictive laboratory-based models would demonstrate high accuracy in determination of high KAM status.
Section snippets
Subjects
Between 2004 and 2008, all sixth through twelfth grade female athlete participants in basketball and soccer were recruited from a county public school district with five middle schools and three high schools to participate in a prospective longitudinal study. The goal of the study was to determine potential underlying mechanisms that increase ACL injury risk. First time visits for 744 subjects' were designated for inclusion into the current analyses. Subjects were excluded (n = 46) from the study
Results
Mean and 95% CI for independent variables used in the model development are presented in Table 1, together with the correlation coefficients of the clinic-based surrogate predictor to its laboratory-based principal (Myer et al., in press-a) independent variable. The initial prediction of high KAM, was performed using logistic regression analysis in the training dataset (N = 598). The final logistic regression model, which included the independent predictors: knee valgus motion, knee flexion RoM,
Discussion
The purpose of the current study was to develop a “clinician friendly” landing assessment tool derived from the highly predictive laboratory-based measurements that would be easy to use and would facilitate the potential for widespread use in clinical and field settings. A nomogram was developed from the logistic regression analyses that can be used to predict high KAM (> 21.74 Nm KAM) based on clinically measured tibia length, knee valgus motion, knee flexion RoM, body mass and quadriceps to
Conclusion
ACL injury leads to significant short-term disability and currently there is no treatment that effectively prevents the long-term debilitation associated with osteoarthritis that follows this injury. Thus, prevention of ACL injuries is crucial. The current study addresses the increased potential to reduce ACL injury and potentially the long term osteoarthritis risk via identification of simple clinical measures that can be used to asses high KAM landing mechanics. Specifically, we have defined
Acknowledgements
The authors would like to acknowledge funding support from the National Institutes of Health/NIAMS Grants R01-AR049735, R01-AR05563 and R01-AR056259. The authors would like to thank Boone County Kentucky, School District, especially School Superintendent Randy Poe, for participation in this study. We would also like to thank Mike Blevins, Ed Massey, Dr. Brian Blavatt and the athletes of Boone County public school district for their participation in this study. The authors would also like to
References (42)
- et al.
A comparison of dynamic coronal plane excursion between matched male and female athletes when performing single leg landings
Clin. Biomech.
(2006) - et al.
A comparison of knee joint motion patterns between men and women in selected athletic tasks
Clin. Biomech.
(2001) - et al.
Sagittal plane biomechanics cannot injure the ACL during sidestep cutting
Clin. Biomech.
(2004) - et al.
Osteochondral microdamage from valgus bending of the human knee
Clin. Biomech.
(2009) - et al.
Anterior cruciate ligament injury in national collegiate athletic association basketball and soccer: a 13-year review
Am. J. Sports Med.
(2005) - et al.
Musculoskeletal dynamics, locomotion, and clinical applications
- et al.
Knee injury patterns among men and women in collegiate basketball and soccer. NCAA data and review of literature
Am. J. Sports Med.
(1995) - et al.
Mechanisms of anterior cruciate ligament injury
Orthopedics
(2000) - et al.
A comparison of knee kinetics between male and female recreational athletes in stop-jump tasks
Am. J. Sports Med.
(2002) - et al.
Application of the joint coordinate system to three-dimensional joint attitude and movement representation: a standardization proposal
J. Biomech. Eng.
(1993)