Tear that results in L knee weakness on the tip toe

During a performance of the French Cancan, I was hopping repeatedly on my L leg, when I felt a pop behind my L knee and my leg and knee gave way. I could no longer stand. I eventually stood up and when I tried to go on the ball of my left foot with a straight leg, the left knee gave way one more time. No swelling, minor discomfort and minor pain in the knee area. Alot of abuse to this leg as R knee had previous ACL/Miniscus surgery.