Biomechanics of different fixation methods for anterior cruciate ligament reconstruction with hamstring tendon grafts on femur

Objective To study the biomechanics of different fixation methods for reconstruction of anterior cruciate ligament（ACL） with hamstring tendon grafts on femor. Methods ACL was reconstructed with 4 hamstring tendon grafts for 32 knee joints of freshly frozen cadavers and fixed with Endobutton, Rigidfix, Hamstring tendon knot, and interface screws, respectively. The displacement at 100N and 400N, failure load, and maximal load were measured to calculate the stiffness after cycling load was detected. Results The maximal load and failure load of Endobutton were the highest followed by those of Rigidfix, Hamstring tendons knot, and interface screws（P＜0.01, P＜0.05）. No significant difference was found in the fixation strength of rigidfix, hamstring tendons knot and interface screws, as well as in displacement at 100N and 400N, stiffness. Conclusion The 4 different fixation methods can meet the biomechanics of reconstructed ACL with hamstring tendon grafts on fermur. The displacement and stiffness as well as the fixation strength of rigidix have certain advantages in biomechanics.