| Objective:Through dissection and biomechanical experiment,to research the histological features of Lisfranc ligament ,then to explore the related characteristics of its axial tensile fracture one-time and the mechanical properties of different fixed materials after it rupture. While combining with the material analysis clinical cases Lisfranc injury, they can provide the theoretical basis for clinical surgery.Method:1. The 11 side of fresh-frozen foot specimens (provided by the Second Hospital of Tangshan) were observed.2. Under Surgical microscope in 10 times, the fresh-frozen foot specimens were dissected to measure the length, width and thickness of Lisfranc ligament.3. The mechanical properties of Lisfranc ligament were determined with CSS-44020 biomechanical testing machine (Changchun Testing Machine Institute) (bio-mechanical testing machine installed TestExpert.NET test software)4. After Lisfranc ligaments rupture and anatomic reducation ,each specimens was fixed with three methods:Ф2.0 mm Kirschner,Ф3.0 mm hollow screw,Ф4.0 mm hollow screw, Of which mechanical material properties were determined .We obtain the data and the statistically analyzed.5. The collected data were analysed by using statistical software SPSS .The data were described by the form (mean±standard deviation) (P <0.05, the differences were significant).Results: 1.The result of the dimensions of Lisfranc ligamentTable 1. Anatomic data((x|-)±S,mm) (?)Test Project Length Width Thickness Lisfranc ligament 10.05±1.07 7.03±0.9 3.30±0.2 (?)2.The result of biomechanical propertiesTableTable 2. Biomechanical data((x|-)±S) (?)Test Project Number Fm(N Wt(N.m Rf (N/m) (?)Lisfranc ligament 11 385.40±108.47 8.15±5.43 211.97±53.5 1Ф2.0mmK-wire 11 68.23±12.75* 0.32±0.08* 37.50±8.10*Ф3.0mm hollow screw 11 215.27±24.05* 2.08±0.63* 06.86±27.79*Ф4.0mm hollow screw 11 326.61±14.39 3.073±0.36 193.15±46.91 (?)statistic—F=67.42 F=48.66 F=17.50—P< 0.05 P< 0.05 P< 0.053. The result of retrospectie case reviewTable 3. clinical data ((x|-)±S) (?) Treatment group Number (n=116) AOFAS Score (?) Fine Good Fair Poor Good rate pФ2.0mmK-wire 77 14 32 24 7 59.7%Ф3.0mm hollow screw 23 6 8 6 3 60.9% <0.05Ф4.0mm hollow screw 16 8 7 1 0 93.8%Total 116 28 47 31 10 64.7%(?)Conclusion:1.By the anatomy and HE staining of Lisfranc ligaments, we can know: The Lisfranc ligament originates from the plantar lateral first cuneiform, with a deep band attaching to the base of the second metatarsal and one band attaching to the third metatarsal.2. In tensile test, The Lisfranc ligament is the strongest. Next are the fixation ofФ4.0 mm hollow screw, the fixationФ3.0 mm hollow screw, the fixation ofФ2.0 mm Kirschner .3. Through retrospective clinical study, we can see: There were statistical differences between the the fixation ofФ4.0 mm hollow screw group group and the fixation ofФ3.0 mm hollow screw group as well as the fixation ofФ2.0 mm Kirschner group(p<0.05).4. From the 1.2.3. Point the conclusion, the same conclusion can be drawn: The lisfranc ligament is short but strong. So we can't reconstruct lisfranc ligament by Suturing after it rupture. The study indicates that anatomical reduction and internal fixation withФ4.0 mm hollow screw can reconstruct lisfrancligament, which contributes significantly to stabilizing the second metatarsal to the first cuneiform. The the fixation ofФ4.0 mm hollow screw group group is better than the fixationФ3.0 mm hollow screw group as well as the fixation ofФ2.0 mm Kirschner group. And the gasket can improve the strength of the fixation.However, these studies are very small, with a small number of fresh-frozen foot specimens, so they may bring some bias and be not really established. Meanwhile the experiment is tensile test from the body and tensile break stress is one of many working mechanisms of fracture such asshearing force. In addition, the mechanical properties of other internal fixation materials need to study such as absorbable screws. |
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