Summary

Tunnel enlargement following PCLR is correlated with radiological and functional outcomes

Abstract

Background

Tunnel enlargement (TE) after anterior cruciate ligament reconstruction has been well described in current literature. However, by far, only few studies concern TE following posterior cruciate ligament reconstruction (PCLR).

Purpose

To determine tunnel enlargement (TE) after single-bundle posterior cruciate ligament reconstruction (PCLR) and its relationship with tunnel angle, posterior tibial slope (PTS), and functional outcomes.

Methods

Patients who received primary single-bundle PCLR were screened. Femoral and tibial tunnel size was measured using an anteroposterior and lateral view of radiographs at least 6 months after surgery. TE is considered significant if the width of the bone tunnel increases by 25% over the drilled size. Tunnel angle and PTS were also measured using radiographs. Functional outcomes were determined using the subjective International Knee Documentation Committee (IKDC) score and the Lysholm score. Baseline characteristics, tunnel angle, PTS and functional scores were compared between the TE group and the non-TE group.

Results

Fifty-four patients were enrolled. TE was observed in 15 femoral tunnels and in 14 tibial tunnels. There was no statistical significance in baseline characteristics for groups with TE and those that do not exhibit TE but a smaller posterior tibial slope (5.7° ± 2.9° vs 7.7° ± 2.3°, P = 0.011) or a steeper tibial tunnel angle in anteroposterior view (80.3° ± 5.0° vs 76.0° ± 5.6°, P = 0.016) is correlated with tibial TE. In terms of functional outcomes, patients who exhibit femoral TE have a lower postoperative Lysholm score (81.1 ± 13.0 vs 90.5 ± 12.3, P = 0.031) and patients with tibial TE have a lower postoperative IKDC score (76.0 ± 17.4 vs 87.1 ± 12.1, P = 0.031).

Conclusions

Tibial TE after single-bundle PCLR is associated with a steeper tibial tunnel angle in the anteroposterior view and a smaller PTS. Femoral and tibial TE are correlated with worse functional outcomes in terms of the lower postoperative Lysholm and IKDC scores.