Reconstruction Of The Medial Patellofemoral Ligament Using Hamstring Tendon Graft With Different Methods: A Biomechanical Study

[Objective]To measure the tensile strength of the medial patellofemoral ligament(MPFL),and to evaluate the biomechanics of different fixation methods of the hamstring tendon graft on the patella.[Methods]Eight fresh cadaver knees were prepared by isolating the patella,leaving only the MPFL as its attachment to the medial femoral,and then the tensile strength and elongation to peak force of the MPFL and its patellar side was measured separately.The MPFL was reconstructed by two different methods,four-suture fixation and suture-anchor fixation.The tensile strength and the displacement to peak force of the MPFL-reconstructed were then measured.[Results]In group MPFL,four failed with a mid-substance tear,while the other four separated from the femur.In group MPFL-P,four failed with a mid-substance tear and four separated from the patella with avulsion fracture.In group four-suture,six failed with suture broken or bone tunnel cut and two avulsion fracture of the patella.All failed with suture broken in group suture-anchor.Compare with their tensile strength,group suture-anchor was similar with group MPFL(P＞0.05),and wick than group MPFL-P(P＜0.05). The tensile strength of group four-suture was stronger than that's of group MPFL-P and group suture-anchor(P＜0.05),which was similar with that's of group MPFL-P(P＞0.05).The elongation of group four-suture was differ with the other three group(P＜0.05).[Conclusions]With regard to their tensile strength, the fixation methods mentioned above are both reliable for clinical use.Compare with suture-anchor method,the four-suture needs no specific implants,which is more economical,convenient and efficient.