Study on Biomechanical Tests of 4 Internal Fixation Techniques for Patellar Fracture

Objective To study the biomechanical properties of four techniques of internal fixation of transvers patella fractures.Methods Twenty fresh cadaver knee joint specimens were divided into 4 groups randomly and transvers osteotomy of the patella were performed. The simulated fractures were fixed with the following 4 techniques:Cerclage wire,Magnuson's wire,AO tension band and Weber's modified tension band. The techniques were evaluated by the KJ-20 biomechanical tests machine. It was defined that the gap of fracture ends ≥1.0mm was fail in internal fixation.Results All techniques were satisfied in 1 kN tensile force of the quadriceps. The AO tension band and Weber's modified tension band techniques resulted better than Magnuson's wire and cerclage wire. But there were no significant differences(P0.05) among the four techniques in resisting the tensile loading within the range of knee motion.Conclusion The operation technique should be properly selected individually in the treatment of patella fractures. The rigid internal fixation and early exercise after operation were required and the unnecessary patellectomy should be avoided.