Bone Tunnel Widening with Autogenous Bone Plugs Versus Bioabsorbable Interference Screws for Secondary Fixation in ACL Reconstruction

Abstract

Background: Use of an autogenous bone plug for the tibial tunnel in anterior cruciate ligament (ACL) reconstruction has been advocated to achieve tendon-to-bone healing. Our hypothesis was that use of an autogenous bone plug, instead of a bioabsorbable interference screw, for secondary fixation of tendon allograft to the proximal part of the tibia would reduce the complication rate and tibial tunnel widening. Methods: We prospectively reviewed the cases of eighty-one patients (average age, 32.0 years) who had undergone ACL reconstruction with Achilles tendon allograft between 2000 and 2006. A bioabsorbable interference screw was used for the tibial tunnel in forty-one patients (group I). These patients were compared with forty patients in whom autogenous bone from the tibia had been used (group II). The two groups were assessed with use of the International Knee Documentation Committee (IKDC), Lysholm, and Tegner activity scores and with KT2000 arthrometer testing. The cross-sectional area perpendicular to the long axis of the tibial tunnel was calculated digitally with use of magnetic resonance imaging (MRI). Results: No significant differences were seen between the two groups with respect to IKDC, Lysholm, or Tegner activity scores or the results of laxity testing with arthrometry. A total of fourteen complications (34%) occurred in group I. In contrast, six complications (15%) were seen in group II (p = 0.046). The mean cross-sectional area enlargement was 38% in group I and 15% in group II (p = 0.017). Conclusions: The clinical results associated with bioabsorbable screws and bone plugs were not significantly different. Laxity evaluation demonstrated no significant differences between bioabsorbable screws and bone plugs. Compared with bioabsorbable interference screws, autogenous bone plugs reduced the complication rate and tibial tunnel widening without inducing instability. We believe that an autogenous bone plug for the tibial tunnel is a reasonable option in selected patients.