I've just replaced my CTi knee brace with a Donjoy Armor knee brace, the difference is incredible in favour of the off the shelf alloy frame Donjoy.
Hinges are better and stronger, frame is engineered better and has a better more supportive design, as you can see one part of the alloy frame passes on top of your thigh and the other or bottom half goes around the back of the calf.
The CTi is just a shell that sits on top of the leg and that you then need to tightly strap in place to get the support. There are issues relating to comfort and circulation with the tightness required on the CTi straps.
The Donjoy does no rely on the straps tightness for support, the straps just hold the leg above and below the hinge, into the frame. You have to actually step into the Donjoy, it does not just sit on top of your leg.
The other thing I really liked about the Donjoy was I could bend the frame with a bit of effort to accomodate the slightly weird shape of my knee and calf muscle.
CTi is carbon frame, had to be custom made to fit me and cost over $1000, Donjoy is stronger and more supportive and cost just $625
They have a high lower frame and they fit with snowboard bindings and wake board boots, which can be an issue with the CTi frame.
If anyone else out there needs info contact Donjoy 02 9479 9306 I have no affiliation, do not sell them etc.
I just wanted to pass on the contact as I know many people have asked me about knee braces over the last 5 years since I began wearing one (CTi).