Mechanisms of Bone Tunnel Enlargement Following Anterior Cruciate Ligament Reconstruction

Although anterior cruciate ligament reconstruction (ACL-R) yields generally favorable results, bone tunnel enlargement (BTE) commonly has been reported after ACL-R. While the exact clinical ramifications of tibial widening on functional outcomes are variable, it is thought that widening may potentially play a role in late failure following ACL-R. The prevalence of tunnel enlargement is related particularly to hamstring autografts, with some authors reporting rates ranging from 25% to 100% in femoral tunnels and 29% to 100% in tibial tunnels after ACL-R. BTE is difficult to manage, particularly in the setting of revision ACL-R. The mechanisms underlying BTE after ACL-R are associated with a complex interplay between biological and mechanical factors.