Preoperative predictors of arthroscopically confirmed lateral ankle micro-instability and two-year outcomes after arthroscopic repair of the ATFL superior fascicle.

BACKGROUND: Lateral ankle microinstability (LAM) caused by anterior talofibular ligament (ATFL) superior fascicle injury is difficult to diagnose preoperatively.

METHODS: Sixty-seven patients with suspected LAM underwent arthroscopy. Preoperative anterior talar translation (ATT), active joint position sense (AJPS), American Orthopaedic Foot & Ankle Society (AOFAS) score, and Karlsson Ankle Functional Score (KAFS) were compared between LAM and non-LAM groups. Logistic regression and Receiver operating characteristic analysis identified predictors. Confirmed LAM cases underwent arthroscopic superior fascicle repair and were followed for 2 years.

RESULTS: Forty-five patients had confirmed LAM. ATT and AJPS errors were significantly greater in the LAM group. ATT and AJPS error at 10° plantar flexion were independent predictors. The combined model showed excellent discrimination (AUC, 0.90). At 2 years, ATT, AJPS, AOFAS, and KAFS improved significantly after arthroscopic repair procedure.

CONCLUSIONS: Combined assessment of ATT and AJPS improves preoperative prediction of LAM. Arthroscopic ATFL superior fascicle repair was associated with improved stability, proprioception, and function.

LEVEL OF EVIDENCE: Level III.