Functional ultrasonography in the diagnosis of acute anterior cruciate ligament injuries: a field study.

Functional ultrasonography is a rapid and inexpensive method of diagnosing anterior cruciate ligament (ACL) injuries. In previous studies, we assessed the diagnostic accuracy of this innovative method by experienced sonographers. The objective of the present study was to investigate whether an examiner without specialist expertise in arthrosonography can achieve similar positive results and whether this technique is effective as a screening tool that can help reduce the number of undetected ACL injuries. After a short period of training, a single examiner prospectively measured anterior tibial translation by ultrasonography in the injured and healthy knees of 41 patients with acute knee trauma. An ACL rupture was presumed to be present if the side-to-side difference in tibial translation exceeded 1 mm (Delta D>1 mm). All patients who were enrolled in the study underwent arthroscopy or at least magnetic resonance imaging (MRI). Ultrasonography revealed the presence of an ACL lesion in 32 of 33 patients with arthroscopically confirmed ACL rupture (sensitivity: 97%, specificity: 87.5%). The mean side-to-side differences (Delta D) between injured (3.8 mm+/-1.5 mm) and uninjured ACLs (0.1 mm+/-0.7 mm) were statistically significant (p<0.05). Our study shows that an examiner without specialist knowledge in ultrasonography can accurately diagnose acute ACL injuries using functional ultrasonography. No additional mechanical tests (KT-1000/KT-2000) or MRI examinations are required. Functional ultrasonography is easy to learn and ensures a high level of diagnostic accuracy. It is well suited for applications in private practices and smaller hospitals with basic medical/surgical care.