Implementation of a semiautomatic method to design patient-specific instruments for corrective osteotomy of the radius.

ABSTRACT

PURPOSE: 3D-printed patient-specific instruments (PSIs), such as surgical guides and implants, show great promise for accurate navigation in surgical correction of post-traumatic deformities of the distal radius. However, existing costs of computer-aided design and manufacturing process prevent everyday surgical use. In this paper, we propose an innovative semiautomatic methodology to streamline the PSIs design. METHODS: The new method was implemented as an extension of our existing 3D planning software. It facilitates the design of a regular and smooth implant and a companion guide starting from a user-selected surface on the affected bone. We evaluated the software by designing PSIs starting from preoperative virtual 3D plans of five patients previously treated at our institute for corrective osteotomy. We repeated the design for the same cases also with commercially available software, with and without dedicated customization. We measured design time and tracked user activity during the design process of implants, guides and subsequent modifications. RESULTS: All the designed shapes were considered valid. Median design times ([Formula see text]) were reduced for implants (([Formula see text]) = 2.2 min) and guides (([Formula see text]) = 1.0 min) compared to the standard (([Formula see text]) = 13 min and ([Formula see text]) = 8 min) and the partially customized (([Formula see text]) = 6.5 min and ([Formula see text]) = 6.0 min) commercially available alternatives. Mouse and keyboard activities were reduced (median count of strokes and clicks during implant design (([Formula see text]) = 53, and guide design (([Formula see text]) = 27) compared to using standard software (([Formula see text]) = 559 and ([Formula see text]) = 380) and customized commercial software (([Formula see text]) = 217 and ([Formula see text]) = 180). CONCLUSION: Our software solution efficiently streamlines the design of PSIs for distal radius malunion. It represents a first step in making 3D-printed PSIs technology more accessible.