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Sex based differences in geometry and tensile properties of the ACL

Anterior Cruciate Ligament (ACL) is an important ligament in the knee which stabilizes the knee during various daily activities. It is well known that female athletes tear their ACL 2-8 times more frequently than their male counterparts. In sports such as soccer and basketball the higher female ACL failure rate is glaring. Higher rates of ACL injury in women translate to more ACL replacement surgeries, more revision surgeries, and a higher chance of developing arthritis.

 

 

 

 

 

 

 

 

 

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In this project, it is hypothesized that females have smaller and weaker (inferior material properties) ACLs when compared to males. It is further hypothesized that such differences in mechanical properties are related to sex based differences in ultrastructure of the ACL. Furthermore the force generated in the ACL is inversely proportional to the intercondylar notch width. Finally it is also hypothesized that no sex based difference exists in mechanical properties of patellar tendon. The objective of the project is to investigate if differences exist between sexes in ACL length, volume, mass density, cross-sectional area, maximum load at failure, maximum deformation at failure, stiffness and energy absorbed before failure after adjusting to various covariates. Correlation between the measured parameters and predictors such as age, height, notch width and mass of subjects will also be investigated. A mathematical model predicting the strength of the ACL from predictors such as age, sex and tissue size will be developed.A new non-contact method to determine area and volume of the ACL by 3-D image reconstruction has been developed. Cadaveric knees have been tested for their anthropometry and mechanical properties.

3D Model of the cadaveric ACL

Tensile Testing of cadaveric ACL

Initial results indicate that female ACLs are not only smaller in size but also have inferior mechanical properties. This result is believed to have high clinical and biomechanical importance. This research is expected to give further insight into the cause for gender disparity in ACL injury thus a clinical remedy could be found.