The anterior cruciate ligament is a ligament located within the knee joint that stabilizes the joint and prevents the lower leg bone (tibia) from sliding forward under the thigh bone (femur). When the ACL is severely twisted or under excessive stress, it can tear, causing the knee joint to “go limp” and not support the body. Sports medicine statistics show that men and women have different rates of ACL injury when playing the same sport. Women are twice as likely to have an ACL injury in basketball as men; in soccer, women are four times more likely to have an ACL injury than men. Women have more ACL injuries than men in sports, and the reason for this, sports medicine experts suggest that the main reason is that women have improper posture in sports, especially non-professional athletes, for example, when jumping to the ground women can not achieve the same bending degree as men, resulting in the knee joint to bear several times the pressure of the body weight, which can easily lead to ACL injuries. However, a recent study by Chistopher J. Wahl, MD, a sports medicine scholar at the University of Washington, measured the geometry of the knee structures of patients with ACL injuries by magnetic resonance imaging (MRI) and concluded that the anatomical features of the knee joint in women differ from those of men in that the tibial plateau (calf bone) is smaller in length compared to the femur (thigh bone) and the proximal tibial articular surface and lateral femoral articular surface are more convex. The proximal tibial articular surface and lateral femoral articular surface are more convex. A short, highly convex articular surface can make the knee less stable with respect to tibial anterior translation and rotation. The results of this study may go some way to explaining why women are more likely than men to have ACL injuries, even in highly trained professional athletes. Reminder: ACL injuries should be properly diagnosed and treated, otherwise secondary damage to the meniscus (cushioning cartilage) within the knee joint will be inevitable. Without the cushioning protection of the meniscus, the tibia and femur will s-bang into each other, causing further damage.