Short and proximalized interference screw fixation leads to tibial tunnel bone re-growth and better hamstring graft integration in ACL reconstruction.

PURPOSE

The stability of the graft in the bony tunnels is of utmost importance in the anterior cruciate ligament reconstruction (ACLR) since it ensures safe healing at the tendon-bone interface. The hypothesis was that when a double tibial fixation was used in ACLR with a short graft of autologous hamstrings, tibial tunnel bone re-growth and better graft integration would be observed at short-term follow-up.

METHODS

The analysis included a cohort of 112 patients after a primary ACLR with hamstring tendons who underwent postoperative magnetic resonance imaging (MRI) 3.0-Tesla (3.0-T) 6 months after the surgery. The patients were divided into three groups based on the tibial fixation technique: 40 had a screw (group S), 35 had a screw and cortical button (group S + B) and 37 had a screw and anchor (group S + A). Two orthopaedic specialists independently evaluated the images, who measured the screw-free tunnel space, and assessed the presence of bone filling in the free tunnel. Furthermore, Ge's protocol was used to determine the graft healing in the tunnel.

RESULTS

In 94 patients a screw-free tunnel space was detected, and a filling of the tunnel was reported in 80.85% of the cases (76 patients), being partial in 15.79% (12 patients) and complete in 84.21% (64 patients). Patients who presented better graft integration (Ge1) had significantly higher values of screw-free tunnel length compared to the other ones who had lower graft integration (Ge3)(p < 0.05).

CONCLUSIONS

At 6 months postoperative MRI, tibial tunnel bone re-growth and graft-tunnel tibial integration after hamstring ACLR is significantly associated with the presence of free space between the anterior tibial cortex and the most distal portion of the interference screw, hence the use of a short and proximalized interference screw is suggested to restore bone stock after hamstring ACLR.

LEVEL OF EVIDENCE

Level IV retrospective comparative cohort study.