gms | German Medical Science

Objectives/Interrogation: To reproduce anatomical reduction and appropriate implant placement during the osteosynthesis, we developed a 3D preoperative planning software for the elbow fractures. The objective of this study was to assess the usability and reproducibility of the 3D preoperative planning software for the osteosynthesis of distal humerus fractures.

Methods: 1. Trial application phase: From our database of previous elbow fracture patients, we investigated how much slice width of CT scan is appropriate for a 3D preoperative planning. We created 3D images of the fracture site from the different slice widths of CT data. Fracture reduction, implant choice and placement were simulated with those images. After the simulation, we compared 3D images created from postoperative CT images with those from the simulation.

2. Clinical application phase: 3D preoperative planning were applied for four distal humerus fracture cases (mean age: 65.8, one male and three females). The preoperative planning were performed in order to determine the reduction, placement and choices of implants. Surgeons performed the reduction and the placement of implants while comparing images between the preoperative plan and fluoroscopy during surgery. After the operation, we carried out CT scans and verified accuracy of the reduction and implants choices and placements. The reductions were evaluated with an angle between the diaphysis axis and a line connecting the medial epicondyle with the lateral epicondyle (ΔC) and an angle between the diaphysis axis and the articular surface (ΔJ) in the coronal plane and distance between the anterior diaphysis and the anterior articular surface in the sagittal plane (ΔD) for the 3D images of distal humerus. The reproducibility was evaluated by the differences of the parameters between pre- and post-operative images.

Results and Conclusions: In the trial phase, it was found imaging slices less than 2 mm was favorable to simulate reduction for the fragments. In the clinical application phase, the fracture types of the patients were A1, A3, C1 and C2 according to the AO classification. We applied double plates in three cases and a single plate in one case. The planned sizes of plates were used for all cases. In the results of reproducibility, differences of the measurements ΔC, ΔJ and ΔD were 2.0°±1.7°, 0.7°±2.4° and 1.9 mm±3.7 mm, respectively. 3D preoperative planning allows visualization of the reduction process and implant placement. It may be helpful for acquiring practical images of osteosynthesis.