Can virtual touch tissue imaging quantification be a reliable method to detect anterior talofibular ligament type I injury at the acute, subacute, and chronic stages?

Background: Anterior talofibular ligament (ATFL) injury affects ankle joint stability. To date, very few studies have examined tissue stiffness changes inside injured ligaments. Virtual touch tissue imaging quantification (VTIQ) allows for the non-invasive quantitative measurement of tissue stiffness. The present study aimed to examine the efficacy of VTIQ as a method for detecting ligament injury. Methods: A total of 206 patients diagnosed with unilateral ATFL type I injury (81 acute cases, 69 subacute cases, and 56 chronic cases) were reviewed retrospectively. Shear wave velocity (SWV) values were collected from both the injured and non-affected sides of the ATFL using a virtual touch tissue imaging quantification technique (ACUSON Oxana 2, Siemens Medical Solutions USA, Inc.). Results: The average SWV of injured ATFL was 4.09 +/- 1.15 m/s in the acute group, 5.60 +/- 1.39 m/s in the subacute group, and 7.74 +/- 1.44 m/s in the chronic group (P<0.001). The SWV values of the ATFL on the non-affected side were almost identical (acute 7.50 +/- 1.12 m/s, subacute 7.53 +/- 1.06 m/s, and chronic 7.61 +/- 1.30 m/s; P>0.05). The injured ATFL had a significantly lower SWV value than the non-affected ATFL in the acute and subacute groups (P<0.001); however, there was no significant difference in the chronic group (P>0.05). Concerning the validity of SWV as a predictor of acute and subacute ATFL injury, the receiver operator characteristics curve analysis showed that the best cut-off point for SWV was 6.165 m/s, with 84.3% sensitivity, 88.5% specificity, and an area under the curve of 0.93 (95% CI, 0.90-0.95). Conclusions: VTIQ is a reliable sonographic method for detecting acute and subacute ATFL type I injury.