Development of Patient Specific Ankle Foot Orthosis through 3D Reconstruction Morshed Alam 1 , I. A. Choudhury 1 and M. Azuddin 1 1 Manufacturing System Integration, University of Malaya, Malaysia Abstract. Designing and manufacturing methods of assistive devices involve manual techniques such as casting molding of the limbs to be treated. Such methods require skillful labor and often based on trial and error rather than systematic engineering and evidence based principles. 3D scanning allows computer aided design tools to be incorporated, however, this approach also relies on the external model. It is difficult to infer axes of rotation of joints from external models. In this article we have demonstrated an approach of designing ankle foot orthosis (AFO) with commercially available ankle joint that facilitate simultaneous viewing of external and skeletal geometry of the limbs. The output model of AFO is compatible with computer aided manufacturing. Keywords: AFO, design, 3D model 1. Introduction Patients suffering from stroke and other neurological disorder have muscle weakness and reduced walking capability. Assistive devices such as ankle foot orthoses (AFO) are prescribed to compensate such impairments. Patient specific orthotic device designing and fabrication requires manual techniques such as casting, making moulds of the limbs to be treated and vacuum forming [1], [2]. Such design and fabrication processes are time consuming, requires skilled labour and often cumbersome for the patients. Moreover, such techniques are based on trial and error rather than systematic engineering and evidence-based principles. Manufacturing of orthotics in these techniques relies on experience of orthotists as the axes of rotation of joints are not inferable from external observations. The axes of rotation are partially specified by the skeletal structure. Development of digital models of freeform surfaces of the anatomy of human body parts by 3D scanning allows incorporating computer aided design. Several articles [1]-[3] are found exploring the feasibility of computer aided design and manufacturing of AFOs based on external modelling. Darling and Sun [4] first designed a simple AFO, not intended to clinical application, through 3D reconstruction of both external and skeletal structure. In our research we have collected CT-scan data of two healthy subjects and developed solid model of external and skeletal geometry through 3D reconstruction. Based on those model computer aided design of AFO for both subjects with commercially available ankle joint (Dream Brace) were developed. Such design of AFO is compatible to computer aided manufacturing and also discards moulding etc. Dream Brace ankle joint of Ortho Inc. uses one way frictional clutch to prevent drop foot, which makes the design feasible for clinical application. 2. Materials and Methods 2.1. Data acquisition CT-scanning of two adult healthy subjects was accomplished keeping the ankle in neutral position. The imaging data of two subjects’ left leg were converted to 3D model through reconstruction. 3D reconstruction  Corresponding author. Tel.: +60146341430; fax: +60-03-79675317. E-mail address: morshed.alam.me@gmail.com. 2014 3rd International Conference on Environment Energy and Biotechnology IPCBEE vol.70 (2014) © (2014) IACSIT Press, Singapore DOI: 10.7763/IPCBEE. 2014. V70. 16 84