Common symptoms of cruciate ligament injury include knee pain, swelling, dysfunction and so on. 1. Knee pain: generally there is a history of obvious trauma, acute onset of the disease, can often feel the tearing sound in the knee joint, after the injury, that is to say, feel the severe pain in the knee joint. 2. Swelling around the knee: simple cruciate ligament injury, swelling is mostly limited to the joint. When the posterior joint capsule rupture, the swelling can spread to the upper and lower back of the knee, and involve the back of the calf, and gradually appear subcutaneous bruises. 3. Functional disorders: the knee joint is usually in semi-flexion after the injury, and the joint flexion and extension are limited. In the late stage, in addition to the history of previous injuries, most of them are commonly characterized by knee tenderness, instability and lameness. If the above symptoms occur, we should be alert to the cruciate ligament injury, and we suggest to go to the hospital in time, combined with the imaging examination, to make a clear diagnosis, and follow the doctor’s instructions for timely treatment, so as not to delay the condition.