131 Acute Injury of The Ulnar Collateral Ligament: Does Ultrasound Get a Thumbs Up?

Ulnar collateral ligament (UCL) injuries of the thumb constitute frequent trauma presentations. While clinical assessment proves valuable, instances arise in equivocal cases where imaging aids in determining optimal management. This project aims to assess the diagnostic efficacy of ultrasound in identifying UCL injuries. A retrospective analysis was conducted utilizing online medical records system. Patients from the last five years who underwent thumb ultrasounds were identified and inclusion criteria encompassed: acute thumb injuries accompanied by ultrasounds indicative of full-thickness UCL tears and/or Stener lesions. Fifty patients who underwent ultrasounds for acute thumb injuries with UCL concerns were identified. 31 were excluded with normal results or incomplete data. The remaining 19 patients had ultrasound reported complete UCL tears and/or Stener lesions and subsequently underwent operative intervention. The average age was 38.7 years; 58% were female. The median duration from presentation to ultrasound scan was 2 days, and from presentation to surgery was 4.5 days. Eleven patients (63%) exhibited a confirmed complete UCL tear during surgery; 6 patients (37%) had a normal intact UCL. Consequently, the positive predictive value of ultrasound in detecting acute UCL tears within this cohort was 63%. It is known that accuracy of US is operator dependent and with over a third of patients in our cohort being identified as having false positive result following surgery, relying on US findings to proceed to surgery must be cautioned. It remains a valuable non-invasive investigation. For cases where the clinical picture is indeterminate, MRI is now our modality of choice.