The HCI advents have not been fully explored in the field of patient-computer interaction. In this paper, we used the cutting-edge technology of free-hand interaction with Leap Motion controller for stroke rehabilitation. We modified the Fruit Ninja game to use the Leap sensor’s hand tracking data. The combination was prepared for patients with stroke to practice their fine motor control. We conducted a pilot study with 14 patients with stroke to evaluate feasibility of using this system for rehabilitation of upper extremity. The results demonstrated significant correlations between scores generated from the Fruit Ninja game and standard clinical outcome measures, such as the Fugl-Meyer Arm assessment and Box-and-Blocks Test. The qualitative evaluation of the system was also proved successful. To make the system more accurate and responsive, we also proposed a kinematic model of the hand. Using this model allows us to incorporate 3D parameters of the hand in tracking which in turn makes tracking more robust.