The relationship of ACL morphometry and structural composition to anterior knee laxity

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Hsin-Min Wang (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Randy Schmitz

Abstract: Greater anterior knee laxity (AKL) has been identified as a risk factor of anterior cruciate ligament (ACL) injury and could be indicative of a weaker ligament. While ACL morphometry and structural composition have the potential to affect ligamentous strength and resistance to external loadings, little is understood about how ligament size and structure may contribute to AKL. Thus, the purpose of this study was to determine the degree to which ACL morphometry and structural composition collectively predict AKL in active females and males. A cross sectional design recruiting active collegiate females and males were used. AKL was assessed by a knee arthrometer. T2-weighted magnetic resonance imaging (MRI) scans were utilized to obtain ACL morphometry as assessed by ACL volume, ACL width, and ACL cross-sectional area. T1-weighted MRI scans were utilized to acquire femoral notch width. Structural composition of the ACL was assessed by T2* and T2 relaxation times. All AKL and MRI measures were used to determine 1) sex differences in ACL morphometry; 2) sex differences in ACL structural composition; and 3) which ACL morphometric measure and MR relaxation measure were the strongest independent predictors of AKL and the degree to which ACL morphometry combined with ACL structural composition to predict AKL in active females and males. Twenty college-aged active healthy males (180 ± 0.1 m, 84.0 ± 10.9 kg, 23.2 ± 2.9 yrs) and twenty females (167 ± 0.1 m, 61.9 ± 7.2 kg, 21.3 ± 2.3 yrs) were measured for AKL and underwent MRI testing on the left knee. Results revealed that males had 30% larger ACL volume and 18% larger ACL width than females, with no sex difference in ACL cross-sectional area. There were no significant differences between sexes in ACL structural composition as assessed via T2 and T2* relaxation times. ACL volume was the strongest morphometric predictor of AKL in both males and females. Smaller ACL volume and lower T2 relaxation times collectively predicted AKL in females (R2=.68), whereas smaller ACL volume and higher T2* relaxation times collectively predicted AKL in males (R2=.44). The primary findings collectively indicated that ACL morphometry and structural composition independently and collectively correlated with AKL. Further, females had smaller ACL morphometry than males with the ACL volume likely being the most appropriate measure of ACL size in studies of sex biases in ACL injury. Investigation of factors associated with the established risk factor of greater AKL could advance future prevention efforts to enhance ligament strength.

Additional Information

Language: English
Date: 2016
Injury, Knee, MRI
Anterior cruciate ligament $x Wounds and injuries $x Prevention
Knee $x Magnetic resonance imaging
Knee $x Sex differences
Joints $x Hypermobility

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