For the most severe instability, or for high-performance athletes, the only knee brace you need is the DonJoy Legend. We have tested braces from most major manufacturers and we are convinced that this one is superior. DonJoy provides the absolute best quality braces and is the brand that most surgeons prescribe and most professional teams use. This brace is designed to provide stability for severe ACL,PCL,MCL, and LCL instabilities. This has been scientifically proven! What is the difference between this and a custom ACL brace such as the DonJoy Defiance? The short answer is, about $600. We have not found any significant difference in performance or comfort between the Legend and any custom brace. We have found custom braces to be very expensive. They are probably only necessary if you have a very unusual leg shape (such as very large thigh above the knee, and skinny leg below the knee). Which sports can this brace be used in? We have found this brace is excellent for virtually any sport where you need stability and comfort in addition to joint protection. These include football, soccer, motocross, water-skiing, tennis, and volleyball. Is this a "functional brace" that I should get for when I return to sports? Yes! Different surgeons have different feelings about brace wear after ACL reconstruction. So, if you have questions, check with your surgeon. However, if you surgeon does recommend a brace, then this is the perfect brace for return to high level sports.