| Objective：The posterior medial structure is the Main stability structureIn the Medial knee, sMCL and POL were the most important parts in theposterior medial structure. The two parts maintained the valgus stability androtational stability of the knee joint together. Currently, the treatment forpatients with chronic posterior medial structure injury was almost thereconstruction of the sMCL and POL. However, the operational methodsdidn't unified. The purpose of this study was to compare the anatomicalreconstruction of sMCL and POL and triangle reconstruction of sMCL andPOL. The research make a comparison between the two methods on the effectof recuperating the knee joint valgus stability and rotating stability using abiomechanics torsion testing instrument. It aimed to make sure a bettermethod of reconstruction and provided a theoretical basis for clinic.Method: Totally8fresh-frozen cadaveric knees were used in this study,The knee joint specimens were provided by the Third Hospital of HebeiMedical University. Use3520-AT biomechanics torsion testing instrument toexert the external rotation and valgus on the tibial when the neutral position ofthe knee joint respectively buckled0°,30°,60°,90°and measure the changesof the external rotation and valgus of the knee joint under the four situations:the knee joint specimen was intact, after sMCL and POL were cut offcompletely, after the anatomical reconstruction of sMCL and POL, and afterthe triangle reconstruction of sMCL and POL. The datas were comparedbetween situations with analysis of variance. P<0.05was accepted assignificant.Result: When sMCL and POL were intact, used the biomechanicstorsion testing instrument to exert the internal and external rotation torsion of5N·m on the distal tibia, and measured the external rotation angles when the knees of the tibia bent0°,30°,60°,90°. With knees bent30°, the externalrotation angle was up to (24.83±2.71)°. With knees bent90°, the minimumexternal rotation angle reached to (20.62±3.28)°. After sMCL and POL werecut off completely, the external rotations of the knee joint in various flexionangles all increased than normal ones. With knees bent90°, the externalrotation angle was up to the maximum, reaching to (31.12±3.22)°. With kneesbent0°, the external rotation angle reached the minimum of (26.64±2.83)°.When the knee joint buckled0°,30°,60°,90°, the datas all had significantdifferences compared with the one of intact specimen (P<0.05). After theanatomical reconstruction of sMCL and POL and the triangle reconstructionof sMCL and POL, the tibial external rotation angles in various flexion anglesdecreased apparently compared with the cutting off one. the datas all hadsignificant differences compared with the cutting off one (P<0.05).Besides,compared with the intact knee joint, there were no statistic signification(P>0.05). Besides, Between the two situations compared with each other,there was no statistic signification (P>0.05).When the sMCL and POL were intact, used the biomechanics torsiontesting instrument to exert the valgus and valgus of5N·m on the distal tibia,and measured the vulgus angles. With knees bent30°, the maximum vulgusangle was up to(10.64±1.15)°. With knees bent0°, the minimum vulgus anglereached to (7.20±0.70)°. After sMCL and POL were cut off completely, thevalgus of the knee joint in various flexion angles all increased than intact ones.With knees bent30°, the valgus angle was up to the maximum, reachingto(18.58±2.11)°. When the knee joint buckled0°,30°,60°,90°, the values allhad statistic signification compared with the one of intact specimen (P<0.05).After the anatomical reconstruction of sMCL and POL, the valgus angles invarious flexion angles decreased apparently compared with the cutting offone.The datas all had statistic signification between the two situations(P<0.05). Besides, compared with the intact specimen, there was no statisticsignification (P>0.05). After the triangle reconstruction of sMCL and POL ofthe knee joint, the valgus angles in various flexion angles also decreased apparently compared with the cutting off one. The datas all had significantdifferences between the two situations (P<0.05). Besides, when the knee jointbuckled30°,60°,90°, the datas had no statistic signification compared withthe intact specimen and the anatomically reconstructed specimen (P>0.05).However, when the knee joint buckled0°with full knee extension, the datashad statistic signification compared with the intact specimen and theanatomically reconstructed specimen (P<0.05).Conclusion: For the injury of the clinical knee joint posterior medialstructure, anatomical reconstruction of sMCL and POL and trianglereconstruction of sMCL and POL can both recuperate the rotating stability ofthe knee joint in every angles. Anatomical reconstruction of sMCL and POLcan recuperate the valgus stability of the knee joint in every angle; andtriangle reconstruction of sMCL and POL can recuperate the valgus stabilityof the knee joint when the knees bent30°,60°,90°. With knees bent0°, thevalgus stability was worse than the intact specimen. For the injury of theclinical knee joint posterior medial structure, anatomical reconstruction ofsMCL and POL had a better effect on recuperating the valgus stability of theknee joint than triangle reconstruction of sMCL and POL when the knees bent0°. |
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