DUO stands for Dynamic Unloading Orthosis and is a bilaterally articulated knee orthosis with dynamic progressive unloading of the knee joint. It is used in patients with gonarthrosis for stability, correction, relief, and pain relief. The frame can be individually adjusted for varus or valgus and it has a unique joint that during the extension phase automatically angles the orthosis further for increased relief of the knee joint. DUO is excellent for patients with isolated osteoarthritis as well as for patients with combined osteoarthritis and instability problems. DUO is available in prefabricated design and as Custom made as well as for medial or lateral relief.