No tunnel widening following arthroscopic anatomical reconstruction of the lateral ankle ligaments

Introduction: Arthroscopic anatomical reconstruction of the lateral ankle ligaments is an emerging technique for treating chronic ankle instability. One of the known complications of arthroscopic anterior cruciate ligament reconstruction is tunnel widening; this makes revision more complicated. The aim of this study was to look for tunnel widening in the postoperative course of arthroscopic ankle ligament reconstruction. We hypothesized that significant widening of the bone tunnels is present 1 year after anatomical ankle ligament reconstruction.

Materials and methods: Twenty-one patients who underwent arthroscopic anatomical reconstruction of the lateral ankle ligaments with a gracilis graft were included prospectively. A CT-scan with 1-mm thick slices with multiplanar reconstruction was done 1 year after the surgery. The size and shape of the tunnels was analyzed, and the ratio of the preoperative to postoperative diameter was calculated. Based on this ratio, the tunnels were given a grade as described by Struewer. Tunnel widening was defined as a grade III tunnel, thus a ratio ≥ 1.3. The tunnel shape was classified as described by Peyrache as cone type, cavity type, line type.

Results: None of the tunnels had widened 1 year after arthroscopic anatomical reconstruction of the lateral ankle ligaments. At the fibula, 81% of tunnels were grade I and 19% were grade II; 57% were cone type and 43% were line type. At the talus, 86% of tunnels were grade I and 14% were grade II. All were line type. At the calcaneus, 86% of tunnels were grade I and 14% were grade II; 57% were cone type and 43% were line type.

Discussion: The main finding of this study was the absence of tunnel widening 1 year after arthroscopic reconstruction of the lateral ankle ligaments.

Level of evidence: IV; retrospective study.