Fitting accuracy of preformed osteosynthesis plates for zygomaticomaxillary complex fractures.

Background: Preformed osteosynthesis plates are a novel treatment option for the fixation of zygomaticomaxillary complex (ZMC) fractures. A preformed plate may improve the reduction accuracy, as an accurate fit and sufficient fixation possibilities are provided.

Purpose: This study aimed to evaluate the virtual fitting accuracy of preformed anatomical osteosynthesis zygoma plates and to assess whether their shape and size are adequate for ZMC fracture treatment.

Methods: The fitting accuracy of three preformed osteosynthesis plates (KLS Martin: zygoma small, zygoma large, and zygoma-paranasal) was evaluated in 100 patients with unilateral ZMC fractures. Using a semi-automatic method, the plates were virtually positioned in their optimal fitting position on the mirrored 3D model of the unaffected side. Overall virtual adequacy was assessed by calculating the plate-to-bone distance and evaluating the fixation possibilities.

Results: The median (IQR) plate-to-bone distances were 0.22 [0.16-0.28] mm (zygoma small), 0.25 [0.20-0.34] mm (zygoma large) and 0.51 [0.41-0.75] mm (zygoma-paranasal), demonstrating a significant improvement in fitting accuracy as the plate size decreased (p < 0.001). The median (IQR) number of available fixation points differed significantly: 6 [5-7] (zygoma small), 7 [6-8] (zygoma large), and 14 [12.25-16] (zygoma-paranasal) (p < 0.001). The zygoma small, zygoma large, and zygoma-paranasal plates were deemed adequate in 97 %, 98 %, and 93 % of the fractures, respectively.

Conclusions: Preformed anatomical osteosynthesis plates for ZMC reconstruction demonstrate an accurate fit, sufficient fixation possibilities, and overall virtual adequacy. These plates are designed to have a high level of anatomical congruence with the zygomatic bone, offering potential advantages in fracture reduction. However, successful clinical implementation requires careful attention to virtual surgical planning, and consideration of the plate rigidity and compulsive fit.