Experimental study of biomechanical stability of reticular loop ligature fixation for tibial eminence fractures

Objective To study the biomechanical stability of reticular loop ligature fixation for tibial eminence fractures by comparing it with cannulated screw fixation. Methods Sixteen fresh porcine knee joint specimens were used in this experiment.After the fracture model was made in uniform size,all samples were randomly divided into reticular loop ligature group (group A) and cannulated screw group (group B),with eight cases in each group.Biomechanical tests were made on Universal electromagnetic and mechanical testing machine.Each specimen was firstly subjected 200 cyclic tests,and then pulled out until it failed.The maximum failure load,yield load,stiffness and displacement were recorded. Results The failure mode of all cases in group A was displacement going beyond the limit.In group B,6 specimens failed as a result of screw pullout from the fracture fragment,whereas the other 2 failed because of the refracture of the fracture fragment.The maximum failure load of group A was higher than that of group B (517.798 N vs 278.769 N,P=00.000),so was the yield load (247.841 N vs 149.063 N,P=00.001).The displacement of group A was lower than that of group B (2.316 mm vs 4.522 mm,P=00.000).Group A exhibited higher stiffness than that of group B(40.062 N vs 38.253 N),but the difference was not statistically significant (P=00.780). Conclusion Biomechanical study demonstrates that reticular loop ligature fixation for tibial eminence fracture has better biomechanical performance than screw fixation does,especially for comminuted fracture and osteoporosis cases.