Features a unique design that not only normalizes patella tracking but also controls knee hyperextension. The patented Cawley Tension Hinge dynamically adjusts the tension applied from the pressure plate on the buttress according to the flexion angle of the knee. As the knee moves into extension, the buttress increases its influence to prevent patella subluxation. The High Performance PTO features aluminum bars for added durability and a flexible buttress for added conformity to the leg.