Of those foot and ankle injuries requiring radiographs based on the Ottawa Foot and Ankle Rules only approximately 22% will have a fracture.

This diagnostic cohort study examined if ultrasound could detect acute non-bony foot and ankle injuries. Ottawa Rules positive patients over 16 years were eligible. An ED member performed scans for injury of tendons and ligaments blind to radiograph findings. Patients without fracture were re-scanned at 2 weeks. The Foot and Ankle Outcome Score (FAOS), a validated, patient-reported outcome measure, was completed at baseline (based on pre-injury status), 2 and 6 weeks.

110 subjects participated. 99 did not have significant radiological fractures. FAOS scores were significantly different at 2 weeks compared with baseline across all subscales (p< 0.000). At 6 weeks a significant difference persisted between scores for the ‘Pain’, ‘Sport’ and ‘QOL’ subscales (p<0.043, p<0.000, p<0.000 respectively) compared with baseline. Initial post-injury USS Anterior Talofibular Ligament (ATFL) findings were significantly predictive of FAOS Subscale results for ‘Symptoms’, ‘Sport’ and ‘QOL’ - respective p values being p<0.004 95% CI (−20.184, −4.402), p<0.029 95% CI (−31.857, −1.896) and p<0.008 95% CI (−32.118, −5.561).

ATFL ultrasound status at the time of injury predicts patient perceived sporting function at 6 weeks.