Bauerfiend Genutrain is what my ortho gave me after my 2nd meniscus surgery. I try to replace it every 2-3 years to maintain elasticity. Recently I have found the Neenca one on Amazon is so identical I can't tell the difference without looking, and is $30 instead of $200 for the Bauerfiend. I have 2 and rotate them now.

EDIT - Bauerfiend Genutrain is now only $100. They also have a hinged model