Pre-operative virtual three-dimensional planning for proximal humerus fractures: A proof-of-concept study

Purpose To (1) evaluate surgeon agreement on plating features (position and screw length) in virtual 3D planning software, (2) describe outcomes (fracture reduction, plate position, malpositioning of calcar screws and screw lengths) of plate fixations planned with routine pre-operative assessment (2D- and 3D CT imaging) and those planned with dedicated virtual 3D software of the same proximal humerus fracture.Methods Fourteen proximal humerus fractures were retrospectively reduced and fixed with virtual planning software by eight attending orthopaedic surgeons and compared to the true surgical fixation with post-operative computed tomography (CT) scans. Reduction differences were quantified using CT micromotion analysis.Results Intraclass correlation for screw lengths was 0.97 (95% CI: 0.96-0.98) and 0.90 (95% CI: 0.79-0.96) for plate position. Mean difference in total fracture rotation of the head between the virtual and conventional group was 22.0 degrees. Plate position in the virtual planning group was 3.2 mm more proximal. There were no differences in inferomedial quadrant calcar screw positioning and, apart from the superior posterior converging screw, no significant differences in screw lengths.Conclusion Reproducibility on plate position and screw length with virtual planning software is adequate. Apart from fracture reduction, virtual planning yielded similar plate positions, screw malpositioning rates and lengths compared to routine pre-operative assessment.