Varus talar tilt combined with an internal rotation pivot stress assesses the supination instability vector in lateral ankle ligaments’ injury — cadaver study

Background: The lack of consensus on the relevance of the varus talar tilt test (VTTT) might be due to the divergence between the insufficiency vector of lateral ankle instability and the direction of this clinical test. Our hypothesis is that the VTTT is more accurate to diagnose lateral ankle ligaments rupture when it's applied with a pre-positioning of the foot in internal rotation (IR). Methods: We compared, in 12 cadaver ankles, the varus opening during a classic VTTT with the same test starting in an IR pivot, using a new arthrometer. Results: The classic VTTT caused a 13° tilt after ATFL section and 23,8° after ATFL and CFL section. The application of a VTTT with an IR prepositioning caused a 21,2° tilt after ATFL section (p = 0,002) and 29,5° after ATFL and CFL section (p = 0,006). Conclusion: The VTTT is better to identify lateral ankle ligaments' insufficiency when it's applied with a pre-positioning of the foot in internal rotation. The resulting vector is similar to the supination trauma.