Usability evaluation of 3D user interface for virtual planning of bone fixation plate placement

Abstract

Universal pre-contoured plates are commonly used for internal fixation of bone fracture. Optimal plate placement can be determined through visual inspection of the relative position between the plate and the fractured bone as displayed on x-rays. While computer-assisted approaches have been developed to enable the manipulation of 3D models of the bone and the plate in virtual environments, as the 3D models are usually maneuvered using a 2D mouse with the virtual trackball paradigm, the process is counter-intuitive and could hamper system usability. An intuitive 3D haptic device was therefore employed to develop a virtual training system for fixation plate placement. A four-session study over two weeks were conducted with 15 subjects to evaluate the usability of the system, with 2D mouse and 3D haptic device employed as user interface. The effect of force feedback was also studied. A questionnaire was administered at the end of the study to assess user satisfaction towards the usability of the two input devices. User performance of virtual plate placement using a 3D haptic device was found to be superior to that using a 2D mouse, in terms of completion time and accuracy. The performance with and without force feedback was not significantly different. Preference toward 3D haptic device was reflected from the responses to the usability questionnaire. In conclusion, employing a 3D input device as user interface can potentially facilitate virtual planning of bone fixation plate placement.