Reconstruction Of Popliteal Tendon At Femur Different Sites In Posterolateral Complex Injury:A Finite Element Analysis

Objective Three-dimensional finite element models with different flexion angles of the knee were established including posterolateral complex,and the changes of tibial rotation angle were compared when the popliteus tendon was reconstructed at different locations on the femoral side,to investigate the optimal site of reconstruction after popliteal tendon injury.Method MRI scanner was used to scan the knee joint of healthy adult male,and 5 flexion angle image data of knee were obtained,including 0°、30°、60°、90°、120°,and application of Mimics,Geomagic Studio and other software to establish three-dimensional finite element models and verify its validity.External rotation load of 10N·m was applied to the tibia under 4 conditions at different flexion angles(intact knee,complete rupture of posterolateral complex,the popliteus femoral insertion was reconstructed 18.5 mm in front and below the lateral collateral ligament insertion and 11 mm below the lateral collateral ligament insertion)the external rotation angle of tibia were observed.Results Under normal circumstances,the knee has a certain degree of physiological external rotation at any knee flexion angle,and the external rotation angle is maximized at 30° of knee flexion.When the posterolateral complex was ruptured,the tibial external rotation angle increased significantly,and the trend was the most obvious when the knee was flexion 0°.When the posterolateral complex was reconstructed,the popliteal tendon could restore the stability of the knee at both sites,and the external rotation angle was smaller than that of the normal knee joint;When the flexion was 0°、60°、90°、120°,the external rotation angle of the tibia was the smallest when the popliteal tendon was reconstructed 11 mm below the lateral collateral ligament insertion,and the second was reconstructed 18.5 mm in front and below the lateral collateral ligament insertion.And at 30° flexion,the results are just the opposite.Conclusion The results of finite element analysis showed that the reconstruction of the posterolateral complex with popliteal tendon 11 mm below the insertion of the lateral collateral ligament,which was most effective in restoring the stability of the knee joint.When the knee was reconstructed 18.5 mm in front and below the lateral collateral ligament insertion,the stability of the knee was restored,but the ability to maintain the stability of the knee was relatively poor,it is recommended that the bone tunnel should be located 11 mm below the lateral collateral ligament insertion during the popliteal tendon surgical reconstruction.