A lockable hinge for use in orthopedic braces is provided. When used in a knee brace, the present hinge provides a knee-immobilizing brace that assists persons with standing and/or walking. The hinge is easily converted from a locked mode to a free range of motion mode and vice versa. When the hinge is in the locked mode, patients are better able to stand and walk. With the push of a button, the patient can bend his or her knee to sit or lie down more comfortably. When the hinge is in the free range of motion mode, patients are better able to participate in physical therapy activities without the hinge locking.