I tore my acl and meniscus by jumping from what I thought was a reasonable height. Evidently all my weight landing on one leg was too much. Did indeed hear a "pop". I remember talking with doctor and they mentioned to me that football players often tear their acl/meniscus and "don't immediately realize" because of the all the surrounding muscle that compensates. In my case, I immediately realized.

Nearly two decades later, this cadaver* replacement feels much stronger than the stock.

*I also learned you could opt for your own tissue or from a cadaver. With your own tissue, recovery was longer. With cadaver, they cautioned there was a "non-zero" (read:infinitesimal) chance of contracting HIV. I thought that was an unusual disclaimer.