Abstract
Category:
Ankle
Introduction/Purpose:
Fixation of the posterior malleolar fracture with plate or screws is under debating. A fatigue loading system and a spatial motion capture system will provide a theoretical basis for the selection.
Methods:
Thirty-six below-knee specimens with Haraguchi I type posterior malleolar fracture model was obtained. The specimens were randomly divided into two groups, Group A used two parallel-placed 3.5 mm semi-threaded hollow titanium alloy screws to fix the fracture from back to front; group B used an anatomical plate to fix the posterior malleolus. According to the ratio S of the area of the sagittal fracture over the total area of the distal tibial articular surface, each group was subdivided into three groups recorded as A1, B1; A2, B2; and A3, B3. In group A1 and B1, S=1/4; in A2 and B2, S=1/3; in A3 and B3, S=1/2. In the simulations of gait cycle, 4 kinds of ankle joints were subjected to mechanical loading. A fatigue loading system was used for repeated loading. The spatial motion capture system was used to measure the displacement X (mm) in the final stage of loading.
Results:
At different locations and different loading conditions, the posterior malleolar fracture displacement X in the three groups of posterior malleolar fracture showed no statistically significant difference.
Conclusion:
here is no biomechanical difference between the internal fixation of two parallel 3.5-mm hollow screws and anatomical plate for Haraguchi I type posterior malleolar fractures with an average fracture block height of 19.27 mm.