Biomechanical Evaluation and Clinical Application Report of Various Forms of Modified Tension Band Wiring for Patellar Fracture

Objective The study was conducted to provide experimental relevant data of internal fixation method for patallar fracture clinically. Methods Using cadaver extremitis with the quadriceps tendon-patellar tendon and intact capsular apparatus, the tibia and femur were mounted in an Instron Materials Testing System , and the tibiofemoral joint was held at 36° of flexion. Tension was applied to the patellar through the quadriceps tendon and fracture displacement was measured with linear motion transducers. Displacement of 3mm was considered to represent failure of fixation. AO tension band wiring, Xu's tension band wiring, figure of eight tension band wiring and Magnusson wiring were examined respectively. Results The figure of eight and Xu's tension band wiring were more effective than AO tension band wiring. All of them could bear tensive force over 294N and may provide sufficient fixation to allow immediate range of motion after operation. Magnusson wiring could bear force less than 294N, which appeared not firm enough. Accordingly, 42 cases of patellar fracture were treated with figure of eight tension band wiring, the excellent and good results was 95. 2% at follow-up studies ranged from 6 to 26 months. Conclusion Figure of eight tension band wiring should be selected firstly in the treatment of fracture of patellar for its effective fixation.