Biomechanical properties of MIPPO and IMN in the treatment of distal tibial fractures and their effects on fracture healing

WANG Yong; SU Jian-min; LI Zhong-xin; HOU Jiang-wei

doi:10.3969/j.issn.1009-4237.2018.01.007

Abstract：Objective To compare the biomechanical properties of interlocking intramedullary nail ( IMN) and minimally invasive percutaneous plate osteosynthesis ( MIPPO) and its effect on fracture healing in the treatment of distal tibial fractures .Methods Totally 76 patients with middle and distal tibial fractures , who were admitted to Zhengzhou First People's Hospital from Jan.2013 to Dec.2015,were divided into IMN group(38 cases) and MIPPO group(38 cases) randomly.Mazur score was used to evaluate the ankle function of the two groups .The postopera-tive time,healing time and healing rate of the two groups were statistically analyzed .Ten specimens were randomly selected to establish a distal tibial fracture model and were divided into observation group and control group .Two methods were used to fix the fracture .Three-point bending test , axial compression test and torsional strength test were performed to analyze the data .Results There was no internal fixation failure in either groups .In the IMN group,there were 3 cases of delayed union of fracture and 2 cases of nonunion of the fracture .The healing time was (13.6 ±2.1) weeks.In the MIPPO group,all patients achieved bone healing ,and the healing time was (11.3 ± 1.7) weeks.There was no significant difference in ankle joint function between the two groups (P>0.05).The bending deflection ,axial compression deviation and torsion angle in the MIPPO group were greater than those of the IMN group,and there was significant difference between the two groups (P<0.05).Conclusion MIPPO and IMN have advantages and disadvantages in the treatment of distal tibial fractures .MIPPO can reduce surgical trauma , but its mechanical properties are inferior to those of IMN .The clinical application should be strictly controlled .