A biomechanical study of patellar tension plating system for patellar fractures

Objective To investigate biomechanical properties of the patella tension plating system in order to provide a theoretical basis for its clinical application. Methods Thirty-six models of artificial patella were randomly divided into 3 groups (n=12). After transverse patellar fractures were created in the models, the 3 groups were subjected to fixation respectively with Kirschner wire tension band (tension band group), patellar concentrator (concentrator group) and patellar tension plate (tension plate group). Next, 6 specimens from each group were placed on a mechanical testing machine to measure the fracture displacements after 100 cycles of simulated knee flexion and extension movements. Tensile strength tests were performed on the remaining 6 specimens in each group to measure the maximum load at fixation failure. Results The fracture displacement in the tension plate group (0.40±0.26 mm) was significantly smaller than those in the tension band group (2.58±0.72 mm) and in the concentrator group (1.25±0.74 mm) (P<0.05); the maximum load at fixation failure in the tension plate group (1,709±206 N) was significantly greater than those in the tension band group (581±122 N) and in the concentrator group (1,003±211 N) (P< 0.05). Conclusion As a new treatment for patellar fractures, the patellar tension plating system can perform better in biomechanical properties than Kirschner wire tension band and patellar concentrator. Key words: Patella; Fractures, bone; Fracture fixation, internal; Internal fixator; Biomechanics