An Algorithm for Automatic Osteotomy Plate Placement Planning in 3D: Application in Distal Radius Malunion

PURPOSE: Positioning of an osteosynthesis plate is a key step in the preoperative 3D planning processes for the design of patient-specific guides. This step requires considerable time and expertise. To increase 3D planning efficiency, this study aims to develop an automated plate positioning algorithm. METHODS: A robust algorithm was developed to optimize osteosynthesis plate positioning on the distal radius, using STL properties and anatomical landmarks. The algorithm involved alignment, landmark detection, initial placement, and final optimization. Retrospective data of 34 planned radii and corresponding plate positions, including decimated and refined mesh versions, were used to compare algorithm output to manual placement based on runtime, Hausdorff distance, translation, and rotation (mean ± SD, 95% CI), thereby assessing robustness across different mesh resolutions. RESULTS: The average run time for the algorithm was 18.3 ± 16.8 s (95% CI 12.4-24.1 s) compared to a manual placement time of 12.45 ± 4.56 min (single expert, n = 10, 95% CI 9.22-16.28 min). The mean unpaired maximum Hausdorff distance between manual and algorithm placements was 5.5 ± 2.5 mm (95% CI 4.6-6.4 mm). The mean rotation and translation differences were 4.9 ± 3.2° (95% CI 3.8-6.0°) and 3.3 ± 1.7 mm (95% CI 2.8-3.9 mm), respectively. CONCLUSION: In conclusion, while some manual adjustment remains necessary, the algorithm aids in reducing planning time and offers a modular, generalizable framework adaptable to other osteotomy-plate procedures, supporting clinical 3D planning.