The use of robotic assistive devices and exoskeletons to supply movement therapy for the rehabilitation of patients following variety of diseases is noticeably growing presently. In order to provide consistent therapy as well as walking assistance, we are developing a wearable lower-limb exoskeleton robot with an adaptive foot device for better walking ability and enhanced stability. In this paper, we focus on the mechanical design of an active knee orthosis. The proposed kinematic design is inspired by the knee biomechanics. Therefore, it is expected that the proposed configuration will help to provide more natural gait during theraphy sessions of patients or in daily use as a sophisticated system. It is based on efficiently controlling the knee motions with hybrid actuations. The two actuators will be implemented with the proposed design; one as hamstring and the other as quadriceps. It is anticipated that the new system will offer an enhanced walking capacity for the patients.