TIBIAL TUNNEL ENLARGEMENT AFTER ACL RECONSTRUCTION WITH HAMSTRINGS. A COM PARISON OF SINGLE AND DOUBLE POINT TIBIAL GRAFT FIXATION

Abstract

Aim of the study: To evaluate whether additional aperture fixation to distal fixation (two-point fixation or 2P) may diminish tibial tunnel enlargement compared to distal fixation alone (one-point fixation or1P).

Methods: Two groups of patients were evaluated. In group 1P (44pts.) the grafts were fixed on the tibial side, using two 4 mm Mersilene tapes tied over a 10 mm bone bridge created in the anterior cortex. In group 2P, an additional fixation, using 1 absorbable cross pin in 27 pts. and 2 absorbable cross pins (Rigid fix, Mitek) in 24 pts., was performed. AP and lateral radiographs as well as patients evaluation were performed 3, 6 and 12 months post-op. Tibial tunnel size was measured at the widest diameter in both AP and lateral radiographs.

Results: Tunnel enlargement occurred in both groups at 3 months post-op, but not thereafter. In the lateral radiographs, tunnel enlargement was significantly less in group 2P compared to group 1P (p< 0.05). No statistical relationship was found between tunnel enlargement and gender, age, IKDC, and KT 1000 side-to-side difference.

Conclusion: Additional tibial graft fixation with cross-pins seems to diminish tibial tunnel enlargement in the sagital plane. This may be explained by the fact that the cross pins inserted in the coronal plane, reduce tibial graft movements mainly in the sagital plane. The study supports the hypothesis that tibial graft micro-movements during the period of tendon healing to bone (up to 3m) play a role in tibial tunnel enlargement after ACL reconstruction using hamstrings.