Prognostic factors of acute ankle sprain: Need for ultrasonography to predict prognosis

Ankle sprains are one of the most common musculoskeletal injuries. To guide management decisions, a clear insight into the relevant subgroups of patients with a potentially better or worse prognosis is important. This study aimed to evaluate injury severity, using ultrasonography (US), as a prognostic factor of acute ankle sprain and other possible factors including age, sex, body mass index (BMI), level of job activity, and level of sports activity. We retrospectively reviewed 28 patients with acute ankle sprain who reported at initial examination with an acutely twisted ankle. All patients had received a standard physical examination, radiography and standard ultrasound, to diagnose specific ligament injuries and their ankle sprain had been treated using standard conservative management. Various data including age, sex, BMI, level of sports activity, level of daily job activity, and final functional score (Foot and Ankle Outcome Scores, FAOS) were obtained. Mean comparison and correlations were used to assess risk factors. Risk factors associated with functional outcomes were evaluated using a multiple linear regression test. At final follow-up as 1 year after injury, FAOS differed significantly for injury severity, age, and BMI. There were no significant differences in sex, job activity, and exercise levels. The factor most affecting FAOS for both pain (FAOS-Pain) and symptoms (FAOS-Sx) was the number of completely torn ligaments. Age was the most important factor affecting the FAOS-Daily Living Activity (ADL). BMI was the most important factor for sports activity level (FAOS-Sports). Age and the number of completely torn ligaments were both important to FAOS-Sports and quality of life (FAOS-QOL). The severity of injury, defined using US, was a prognostic factor for long-term outcome following acute ankle sprain. Therefore, US imaging of acute ankle ligament injury may be important to predict prognosis of acute ankle sprain.