Additive fabrication of custom pedorthoses for clubfoot correction

Purpose - The purpose of this paper is to determine the most-practical means of transforming computer-aided-design models of custom clubfoot pedorthoses into functional pedorthoses for testing on patients in a clinical trial. Design/methodology/approach - The materials used in conventional orthosis fabrication are not yet available for solid free-form fabrication; therefore, to fabricate the pedorthoses, several approaches were considered, including direct manufacturing, additive-based moulding, laser cutting of foam and combinations of several of these approaches. Findings - The chosen approach of additively manufacturing the custom hard shell, and moulding the polyurethane-foam insert, resulted in accurate, durable and effective pedorthoses that fit well, and could be adjusted as needed. The pedorthoses that were produced are currently being tested on the respective patients for their improvement in mobility and degree of clubfoot correction, and will continue through early 2010. Practical implications - Additive manufacturing provides an ideal approach for generating the custom, end-use hard- and soft-layer patterns: each pedorthosis is truly unique; and the soft layer has regions of variable thickness. The advantage of this approach is the reduction in labour and the increase in degrees of design freedom available, compared to conventional methods of fabricating orthotic devices. Replacement inserts can be moulded in a matter of hours using this silicone-moulding approach. Originality/value - Several new approaches for fabricating custom orthotic devices were explored, and the related results are discussed. The goal of this paper is to convey the potential of the fabrication procedure used and lessons learned on this project to the rapid prototyping and orthotic communities.