Accuracy of Ultrasound Compared to Magnetic Resonance Imaging in the Diagnosis of Thumb Ulnar Collateral Ligament Injuries

This prospective case series compared the accuracy of ultrasound (US) to magnetic resonance imaging (MRI) in differentiating complete displaced (CD) thumb ulnar collateral ligament (UCL) tears from nondisplaced injuries in 10 patients with suspected traumatic thumb UCL injuries. Ultrasound identified 100% (2 of 2) of MRI-documented CD tears, both of which were further confirmed during surgical repair. Ultrasound identified the absence of CD tears in the remaining 8 patients. Although MRI is the reference standard imaging modality for characterizing thumb UCL injuries, ultrasound should be considered an accurate, cost-effective, and alternative imaging modality to differentiate surgical versus nonsurgical thumb UCL injuries.