Three-Dimensional Virtual Planning for Corrective Osteotomies Made a Difference

Abstract

Objective: There is increased clinical use of 3-dimensional (3D) virtual planning and 3D printed patient-specific guides to correct malunited fractures. Previous studies have investigated the accuracy and possible improvements in outcome for this technology. The focus has foremost been on the benefits of the 3D printed guides while little research is done on the impact of the preceding 3D virtual planning. The authors’ experience is that digital manipulation of detailed 3D images uncovers information that can influence the preoperative plan. The main purpose of this study was to examine if the 3D virtual planning process had affected the final choice for treatment. Materials and Methods: This retrospective study reviews a consecutive series of 23 cases of corrected malunited radius fractures, treated between 2011 and 2015. Bilateral, high-resolution forearm computed tomographic (CT) scans were acquired from each patient. With use of Materialise Mimics software, 3D models that could be digitally manipulated were created. For all but 1 patient, the healthy forearm was mirrored and used as a template for correction. Three-dimensional virtual planning took place during web meetings between the surgeon and the clinical engineer. Different osteotomy locations and angles and different fragment positions and osteosynthesis plates were digitally evaluated. This allowed the surgeon to choose his preferred treatment plan based on the virtual plate fit, fragment position, bone contact surface, natural ulnar variance seen on the contralateral side, and evaluation of the distal radioulnar joint congruency after virtual reduction. Our review consisted of comparing the preliminary preoperative surgical plans before interaction with the surgeon and the clinical engineer, derived from 2D planning with either standard radiographs or CT images, with the final chosen 3D surgical plan after interaction. The 3D virtual planning was considered to be different from the preliminary 2D planning when it demonstrated the need for at least 1 of the following: (A) plate contouring, (B) bone removal for improved plate fit, (C) change in osteotomy levels or directions, (D) double level osteotomy, (E) change in ulnar variance from neutral, (F) over- or undercorrection compared with the parameters of the contralateral side, (G) not using the contralateral side as a template for correction, (H) avoiding corrective osteotomy. Results: The preliminary 2D surgical plan before interaction between surgeon and clinical engineer was changed for 14 of the 23 patients. Category A counted 2 cases, B 2 cases, C 4 cases, D 1 case, E 4 cases, F 1 case, G 1 case, and H 2 cases. For the remaining 9 cases, the preliminary preoperative plan was chosen as final procedure. Conclusion: Limitations of this study include the retrospective design. As a consequence, details of the preoperative radiological planning were not comprehensively defined. Even so, this study showed that additional or new information acquired by the virtual planning led to a change of surgical procedure in 60% of the cases. Selection of a more ideal surgical method has the potential to improve outcomes of corrective osteotomies.