Finite Element Analysis of Patellofemoral Ligament Reconstruction in Recurrent Patellar Dislocation
Objective:Based on the traditional"tendon bone"theory,this study investigates the mechanical relationship between the medial patellofemoral ligament(MPFL)and recurrent patellar dislocation through finite element modeling,and investigates the optimal effect point for the reconstruction of the femoral lateral insertion point of the MPFL.Methods:One healthy adult male volunteer aged 29 was selected to undergo 64 slice spiral CT of the right lower limb.Another 5 patients with recurrent patellar dislocation from April 2022 to June 2022 were selected to collect and compare the Lysholm knee joint score,pain visual analogue scale(VAS)score,congruance angle(CA),tibial tubercletrochlear groove distance(TT-TG),and patellar tilt angle(PTA)before and after surgery.Establish 6 groups(normal group,MPFL injury group,MPFL reconstruction group A,MPFL reconstruction group B,MPFL reconstruction group C,MPFL reconstruction group D)to study 4 working conditions of knee joint flexion(30°,60°,90°,120°),and analyze and observe mechanical related indicators(patellofemoral joint internal and external contact pressure,contact area,equivalent stress,MPFL ligament tensile stress,MPFL ligament length,patel-lar displacement changes).Results:In the finite element mod-el of knee joint,the internal and external contact pressure of patellofemoral joint,patellofemoral joint contact area,patellofemoral joint equivalent stress and patellofemoral displace-ment degree gradually increased from 30°-90°,and gradually decreased from 90°-120°.The tensile stress of MPFL at 30°-90° was gradually increased,and that at 90°-120° was gradually decreased.In MPFL reconstruction group D,the internal and lateral pressure values of patellofemoral joint,joint surface contact area and patellar displacement were closer to those of normal knee joint group.After surgery,Lysholm knee joint score of patients was significantly higher than before surgery(P＜0.05),and pain VAS score,CA,TT-TG and PTA were significantly lower than before surgery(P＜0.05).Conclusion:The optimal effect point of MPFL reconstruction on femoral side was verified,and the mechanical effect of equivalent point on the treatment of recurrent patellar dislocation was confirmed,which provided a mechanical basis for the selection of clinical MPFL reconstruction on femoral side.
tendon bundle bonemedial patellofemoral ligamentknee jointrecurrent patellar dislocationfinite element analysis
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