MULTIPLE BONE FRAGMENT CORRECTION IN COMPUTER-ASSISTED OSTEOTOMY OF THE RADIUS

Abstract

Previously, we have described a novel, computer assisted technique of osteotomy for distal radius malunion. Laboratory and clinical results demonstrate excellent realignment of the articular fragment, but incomplete correction of the radioulnar convergence and loss of radial bow. This study describes an innovation whereby both the proximal and distal fragments of the malunited radius are manipulated in 3D relative to an external template. Two case studies demonstrate the improve restoration of anatomy with this technique.

The purpose of this study was to develop a method of computer-assisted planning and image guided surgery to restore the normal bow to the malunited radius.

Manipulation of a virtual model of a distal radius malunion can only restore the full anatomical bow to the radius if both the distal and proximal fragments are corrected to match a normal template.

This is a novel method of restoring normal anatomy in which both fragments of a malunited bone are corrected relative to an external normal template.

A previously developed CT-based research software system for conducting computer-assisted distal radius osteotomy allowed three-dimensional manipulation of the distal fragment only, to restore the alignment of the distal articular surface. Results of the first six cases demonstrated that this system did not fully correct the convergence of the radius and ulna with persistent loss of radial bow, although it does provide excellent realignment of the articular fragment. The system was modified to include the ability to manipulate the proximal fragment of the radius. This fragment is rotated and translated to match an external reference template derived from a mirror image CT surface mesh of the opposite forearm. Results of two case studies are evaluated, demonstrating the computer models and post-operative radiographs confirming improved restoration of radial anatomy compared to the previous system.