This paper is concerned with a compliant-hinge mechanism that can provide a wide range of torque-angle profiles. The mechanism consists of thin-walled open-section shells that are subjected to combined twisting and bending. A pair of open-section shells is so arranged as to get a large rotation about a virtual axis with high stiffness along other axes. A replaceable cam-like guideway regulates the bending of the open-section shells as they twist, thereby generating the desired torque profile. An energy-based, graphical, and computational design method is formulated to obtain the guideway profile for a specified torque profile. A physical prototype is constructed for an assistive chair for the elderly to demonstrate the variable-torque output and the efficacy of the hinge.