Assessment of biomechanical properties of the new two-hole miniplate internal fixation for bony mallet finger treatment by finite element analysis

Surgery is highly recommended for a bony mallet finger when the fracture fragment involves greater than one-third of the articular surface. K-wire based and plated-based internal fixation are widely used for mallet fracture. However, the outcomes of different surgical treatment options make the treatment of the bony mallet finger controversial due to frequent complications. The two-hole miniplate is a new and promising plate-based internal fixation treatment for the bony mallet finger with low complication rates in recent years. The aim of this study was to evaluate the biomechanical parameters (von Mises stress, strain and deformation) of the two-hole miniplate fixation compared to the traditional K-wire-based fixation using finite element analysis (FEA). Further, the biomechanical parameters of each part of the two-hole miniplate internal fixation were also analyzed. The results indicated that the two-hole miniplate model had the minimum von Mises stress value and the displacement of fracture fragment was less than 30 µm. The two-hole miniplate had an apparent compression effect on the avulsion fracture and inhibited the fracture displacement. This study would provide further guidance for clinical application in using the two-hole miniplate internal fixation.