Too many athletes have had to change careers or quit altogether joining MMA and BJJ competitions after they injure their knees in fights or even during practice. Some have gotten injured beyond the normal length of recovery and were reduced to being mere shadows of their former selves when they try to make a comeback bid for their former status or are forced to retire.
Knee injuries and ACL can also happen at the same time, all at once. An awkward land or a funny resulting from evading or stopping a takedown can do much damage. Not only the beyond normal amount of pain but also the knee casts after surgeries and long months of recovery forcing you to stay out of the mat will not be good.
To avoid injury on knees and ACL tears athletes are trained to make sure they have fully warmed up and that they have done enough loosening of their leg muscles and ligaments before exercises and competitions. BJJ and MMA training and competitions are tough and danger and risks are always present. However, damage and injuries can be prevented and mitigated by following correct pre-competition and exercise preparations and wearing the appropriate protective gear.
Knee sleeves and knee pads are good for prevention of any injuries to knees and damage to ligaments and tendons, especially for those who easily pull their knees. Here in this video Kurt Osiander hot rod a pair of Bauerfeind knee pad to supplement the strength of the basic protection the kneepads provide.