A meta-analysis (Wang et al. 2018) in The European Journal of Sports Science states that ultrasound (US) could be an interesting imaging examination to be considered to diagnose ACL injury.
(Dynamic) US examination should be chosen only when there is a high clinical suspicion of an ACL injury. US has a very high sensitivity. When the (dynamic) US diagnosis is positive, suspicion of an ACL injury should be high. But it is still important that ultrasound has a particularly low sensitivity to diagnose incomplete ACL injury. When the diagnosis is negative, it cannot easily rule out the possibility of ACL injury. At that case, a reference standard is still required for verification.
US is a very convenient examination that can also diagnose additional pathologic findings associated with ACL injuries such as joint effusion, and collateral ligament lesions.
The ACL can be partially be seen from the anterior side with extreme flexion of the knee. SonoSkills encourages primary care professionals, or secondary care professionals without access to the preferred imaging techniques, to test the authors findings in patients with a suspected ACL tear.