Anatomic Risk Factors For Primary Anterior Cruciate Ligament Injury In Elite Adolescent Athletes

Objective:To analyze the relationship between the first injury of Anterior Cruciate Ligament（ACL）and the anatomical risk factors of knee joint in elite adolescent athletes.Methods:Retrospective study.From 2016 to 2021,21 elite adolescent athletes with first ACL injury（experimental group）and 21 healthy adolescent athletes matched by age and sex1:1（control group）were selected.MRI was used to measure the posterior tibial slope（PTS）,the notch width,the morphology of the femoral condyle,the notch width index（NWI）,the height of tibial spine,and the meniscus bone angle（MBA）to compare the morphological differences of the knee joints between the experimental group and control group.The anatomical risk factors of knee joint for the first injury of anterior cruciate ligament in adolescent athletes were analyzed by the binary logistic regression,and the receiver operating characteristic（ROC）curve was drawn to evaluate the predictive accuracy and the cutoff value of independent risk factors.Results:The lateral meniscus slope angle（2.64 ± 5.59 ° and-1.1 ± 2.64 °）of adolescent athletes with anterior cruciate ligament injury was significantly higher than the control group（P < 0.05）,the notch width（1.61 ± 0.19 cm and 1.79 ± 0.23cm）,NWI（0.23 ±0.02 and 0.25 ± 0.02）and medial MBA（24.9 ± 3.87 ° and 28.1 ± 4.02）were significantly less than the control group（P < 0.05）.The NWI of male adolescent athletes in the experimental group（0.22 ± 0.02 ° and 0.25 ± 0.03 °）was significantly less than that in the control group（P < 0.05）.The medial tibial slope angle（3.95 ± 2.06 ° and1.52 ± 2.04 °）and lateral meniscus slope angle（1.44 ± 3.75 ° and-1.2 ± 2.75 °）of female in the experimental group were significantly higher than the control group（P <0.05）,the bicondylar width（6.27 ± 0.64 cm and 6.69 ± 0.29cm）the notch width（1.51 ±0.13 cm and 1.70 ± 0.16cm）and medial MBA（25.2 ± 4.07 ° and 28.5 ± 3.72 °）were significantly less than the control（P < 0.05）.The binary logistic regression analysis showed lateral meniscus slope angle,notch width and medial MBA angle were risk factors for anterior cruciate ligament injury in adolescent athletes.The areas under curve were 0.735,0.718 and 0.702,respectively.The lateral meniscus slope angle cutoff value was > 2.4 °（sensitivity 57.2%,specificity 90.5%）,notch width cutoff value was< 16.3mm（sensitivity 76.2%,specificity 61.9%）,and medial MBA angle cutoff value was < 27.9 °（sensitivity 57.1%,specificity 85.7%）.Conclusion:Lateral meniscus slope angle,notch width and medial MBA angle are independent risk factors of ACL injury in adolescent athletes.Lateral meniscus slope angle > 2.4 °,notch width < 16.3mm,and medial MBA angle < 27.9°,are effective predictors of ACL injury in adolescent athletes.There are gender differences in ACL injury risk,the risk of ACL injury in female adolescent athletes is greater than male.