tricky to explain with panache!

rotatory control is about planting your foot on the ground and then controlling the amount of rotating (rolling in or out) your thigh does above it - hence the bit why braces can't fully control this bit.

your cruciate is under greatest strain when your foot is pointing to 2 o'clock and your knee is pointing to 10 o'clock. it's a normal function and usually your cruciate passively controls the extreme's of rotation in your knee. yours being a bit dodgy won't be as efficient so you need your muscles to control this.

you need to practice with your foot static and then get more dynamic with planting your foot. it's all about control - not just doing it. it also gets you to concentrate on not only brute strength around the knee but control around the hip.

as for braces - if you think you need one then your probably not ready to do stuff on it yet! there is no harm in having one, mentally you'll feel tougher but don't rely on it!

cheers

sixphysio