The purpose of this study was to describe the positioning of bone tunnels of arthroscopic anatomical reconstruction of lateral ankle ligaments (AAR-LAL) and identify radiological measurements associated with short-term clinical outcome one year after surgery.

A total of 61 patients were included in this IRB-approved retrospective study. There were 52 men and 9 women, with a mean age of 36.3 ± 10.8 (SD) years. AAR-LAL was performed to treat chronic instability secondary to strain sequelae after failure of conservative treatment. Good short-term clinical outcome was defined by Karlsson-score≥80 (n=40) one year after surgery. Sixteen radiological measurements were studied to characterize the positionings of fibular, talar and calcaneal tunnels (FT, TT and CT, respectively). Feasibility and inter-observer agreement were calculated for each measurement. Receiver operating characteristic curves were used to identify optimal thresholds for measurements associated with outcome at univariate analysis. A binary logistic regression was used to identify independent predictors.

Two measurements were associated with good outcome: distance from the proximal FT entrance to the distal end of the fibula on anteroposterior (AP) view (called ‘AP distal FT’, P=0.005), and the ratio between the distance from TT entrance to the talo-navicular joint and the talus length on lateral view (P=0.009). Optimal thresholds were of >35mm and<0.445, respectively. At multivariate anlysis, only ‘AP distal FT’>35mm remained independent predictor of good outcome (P=0.002).

Radiological evaluation of bone tunnels following AAR-LAL is feasible, reproducible, and helps predict short-term outcome after reconstruction of lateral ankle ligaments.