Purpose: The purpose of our retrospective analysis was to describe results of arthroscopic treatment of painful ankle instability without clinical or radiological laxity.

Material and methods: Eighteen patients, mean age 27 years (seven men and nine women) were operated on by the same surgeon between 1999 and 2000. Sixteen patients (90%) were reviewed by an independent investigator at 20±4 months. Fifteen patients were athletes, ten at the competition level, and five had amateur sports activities. The accident caused forced inversion in 15/16 cases, during sports activities in 85.5% of the cases. Mean age at injury was 17±6 years. Mean time between the accident and arthroscopy was eight years. All patients had pain in the anterolateral region associated with effusion in 50% and apprehension or instability for daily life activities. Standard x-rays were normal in fourteen patients (87.5%). Comparative stress images did not demonstrate pathological laxity. Complementary imaging (MRI, CT scan, arthroscan, ultrasonography) was obtained in six patients with 50% negative results. Arthroscopy revealed anterior tissue interposition (antero lateral in thirteen patients (81%) and anteromedial and anterolateral in three) which was removed with the shaver. Joint cartilage was intact in fifteen patients (81.25%).

Results: At last follow-up, functional outcome was good in all patients who had all resumed their sports activities. Subjectively, six patients felt they had normal function, seven nearly normal function and three abnormal function (81% satisfied or very satisfied). Six patients were symptom free even during intense physical activity. Eight patients reported some difficulties for strenuous exercise and two for moderate exercise. Joint motion was normal in ten patients and 5° dorsal flexion deficit was observed in six. There were no recurrent sprains. The x-ray was normal and identical to the initial image in 87.5% of the patients. Globally, 87.5% of the patients had good or excellent outcome. Two patients had fair or poor outcome.

Discussion: Diagnosis of anterolateral ankle conflict can be established in patients with a compatible history and a typical clinical presentation with normal x-rays. Arthroscopic treatment can remove tissue interposition allowing good functional results and total recovery of sports activities. Complementary MRI or arthroscan have little specificity and poor sensitivity.