Biomechanical analysis on transverse tibial fixation in anterior cruciate ligament reconstructions☆

OBJECTIVE To verify whether the combination of tibial cross pin fixation and femoral screw fixation presents biomechanical advantages when compared to femoral cross pin fixation and tibial screw fixation for the reconstruction of the anterior cruciate ligament (ACL). METHODS Thirty-eight porcine knees and bovine extensor digitorum tendons were used as the graft materials. The tests were performed in three groups: (1) standard, used fourteen knees, and the grafts were fixated with the combination of femoral cross pin and a tibial screw; (2) inverted, used fourteen knees with an inverted combination of tibial cross pin and a femoral screw; (3) control, ten control tests performed with intact ACL. After the grafts fixation, all the knees were subjected to tensile testing to determine yield strength and ultimate strength. RESULTS There was no statistically significant difference in survival techniques in regard to strength, yield load and tension. There was a higher survival compared in the standard curves of yield stress (p < 0.05). CONCLUSION There is no biomechanical advantage, observed in animal models testing, in the combination of tibial cross pin fixation and femoral screw when compared to femoral cross pin fixation and tibial screw.