Augmentation of Tibial Fixation of Soft-Tissue Grafts in Anterior Cruciate Ligament Reconstruction

Purpose: Fixation of the tibial aspect of soft-tissue grafts in anterior cruciate ligament (ACL) reconstruction is problematic. Augmentation of the interference fit in screw application is seen as a means of improving fixation. This study aims to determine the effect of mesh augmentation of interference screw application in ACL reconstruction. Methods: Forty cadaveric ovine hind limbs were harvested at necropsy. A quadrupled hamstring tendon graft (QHT), used in human ACL reconstruction, was simulated. Metal and bioresorbable interference screws were used for tibial fixation in the presence or absence of mesh augmentation. Anterior translation of the reconstruction was determined via radiostereometric analysis; specimens were then subjected to tensile loading, with load to failure and mechanism of failure recorded. Results: There was no improvement in biomechanical properties observed for either the metal or bioresorbable screws with mesh as evaluated by load to failure or anterior translation in this cadaveric model. Conclusions: The use of a synthetic mesh, encompassing the strands of a QHT and interference screw, did not significantly improve the strength or rigidity of the simulated ACL reconstruction performed. Clinical Relevance: Metal interference screws have provided a more secure fixation in the QHT when compared with bioresorbable screws. Augmentation of the reconstruction, by the application of mesh in the tibial tunnel, proved difficult to apply with no observed benefit to either the mechanical or radiologic attributes of the reconstruction.