Do braces actually work in preventing ACL injuries?

No. There are no good large studies demonstrating that braces prevent acl injuries. However, most football players (linemen) in college and the pros use them anyways during play.
No. If there is an anterior cruciate injury, and you use the brace in sports with moderation, then the brace can be successful. Adding a 10 deg extension stop has helped prevent giving way. "giving way" is what happens when you pivot with an acl deficient knee. The brace tries to prevent instability of the knee when pivoting. Unfortunately, it is difficult for any brace the grip the leg strong.
No. There's no evidence to suggest that braces prevent ACL injuries. Some surgeons still recommend a brace for peace of mind and for the brace top act as a reminder that you should be careful when participating in sports.

Related Questions

How to prevent ACL injuries in tennis?

Strengthen. Probably the best way would be to work on hamstring and quad strengthening exercises especially in the offseason the use of plyometric exercises also would be beneficial. If you have significant instability, the use of a stabiliztion brace might prevent more significant injuries. But preseason conditioning would be the key in my mind. Read more...
Prevention exercises. There are specific acl prevention programs that can help train a person how to jump, land, and turn. The essential component is "neuromuscular balance and training." the exercises vary but it is the combination of them and incorporating them into training that prevents injury. Please see http://pt.Usc.Edu/aclprojectprevent/index.Htm for a well known program. Read more...
Stay fit. Keep yourself fit and strong, especially in the quad and hamstring muscle groups. Keep your muscle well stretched out. Wearing a brace may be of some benefit, but there's no factual proof that they prevent ACL injuries. Read more...
Prevent ACL injury. The best way to prevent ACL injuries is to stretch and strengthen the leg muscles, especially the front and back muscles of the thigh (quadriceps and hamstrings). Here are other things you can do that may help prevent ACL injuries: Avoid wearing shoes with cleats in contact sports. Avoid wearing high-heeled shoes. Avoid sports that involve lots of twisting and contact. Read more...

How can one prevent ACL injuries?

Neuromuscular . Neuromuscular training is recommended for acl prevention. Obviously, it depends on the severity of the injury and whether or not your physician has cleared you to begin return to sport training. Read more...
Strength/Flexibility. The best way to prevent ACL injuries is to stay in good shape and keep up great strength and flexibility in your lower extremities. Keep up cardiovascular endurance, to prevent fatigue during activity, which can contribute to ACL tears. Read more...
Prevent ACL injury. The best way to prevent ACL injuries is to stretch and strengthen the leg muscles, especially the front and back muscles of the thigh (quadriceps and hamstrings). Here are other things you can do that may help prevent ACL injuries: Avoid wearing shoes with cleats in contact sports. Avoid wearing high-heeled shoes. Avoid sports that involve lots of twisting and contact. Read more...