Biomechanical Study of Absorbable Screws Tension Band in The Treatment of Transverse Patella Fractures

Abstract：Objective To explore the biomechanical characters and the stabilization of absorbable screws tension band in the treatment of transverse patella fractures. Methods Transverse patella fractures were created in twelve fresh knees and fixed by one of two techniques:(A Group)absorbable screws with a PDS(Polydloxanone Suture)tension band;(B Group) AO tension band. Testing was performed by pull on the quadriceps tendon between a 90° flexed position and full knee exten_sion,the amount of fracture site displacement in simulated knee extension was measured. Results Except for the first cycle, fracture site displacement in flexion and in extension at A Group was significantly higher than that at B Group(P < 0. 05). With the increase of number of cyclic loading,fracture site displacement at A Group and B Group increased gradually(P < 0. 05). A Group failed over 1 200 cycles loading with a failure criterion of 3 mm fracture site displacement. Conclusion Revi_sion surgery to remove the implants is not required regarding the use of absorbable implants for fixation of patella fractures. But the stabilization of this technique is significantly lower than modified tension band. Auxiliary external fixation is necessary.