Consecutive Ankle Sprain Classification and Injury Systematization (CASCaIS), A New Lateral Ankle Sprain Classification Based on the Pivot Test: A Prospective Cohort Study

Abstract

The biggest challenge in the treatment of acute ankle sprain is the uncertainty of the prognosis. The traditional classifications have several interpretations and little correlation with prognosis. In this study we propose a new classification for acute ankle sprain only based on clinical criteria. We prospectively evaluated all patients with an ankle sprain, aged between 18 and 45 years, admitted to a hospital during a 24 month period. The minimum follow-up period was 12 months. The sprains were classified, in the first few days (CASCaIS-Initial), according to autonomous gait capacity, inspection and palpation. After a few weeks (CASCaIS-Deferred), it was complemented with the mechanical evaluation of ligaments through the ankle pivot test. Among the 49 patients who completed the follow-up, none of those who had a pivot-negative test progressed to chronic ankle instability (CAI). Nine of the 33 patients (27%) with a positive pivot progressed to CAI (p = 0.022). The evaluation of CASCaIS-Deferred demonstrated an association with CAI (p = 0.018). This classification proved to be a simple, inexpensive, and reliable tool that clinicians can use to determine the prognosis of the sprain.