Stress MRI assessment of partial anterior cruciate ligament injury based on three-dimensional analysis

Accurate diagnosis of anterior cruciate ligament (ACL) injuries, particularly partial tears, remains paramount for effective clinical management. This study investigates the diagnostic potential of stress magnetic resonance imaging (MRI) employing a dedicated device to induce anterior translation, conducted twice with the device positioned alternately under the thigh and under the tibia. The analysis involved a comprehensive three-dimensional (3D) assessment of displacement factors to correlate the injury type with the actual findings in the arthroscopic examination. The study aims to determine if 3D displacement analysis via stress MRI can precisely localize and characterize specific ligament bundles affected by ACL injuries, correlating these findings with arthroscopic examination results.

Thirty patients with ACL injuries and 17 controls with acute knee pivoting injuries less than 3 weeks old underwent stress MRI examinations. Results were compared against arthroscopic findings to evaluate diagnostic accuracy.

Distinctive 3D displacement patterns were observed for various ACL injuries. Partial tears of the anteromedial bundle were characterized by "2x Lateral Displacement + External Rotation" (P=0.048), yielding an area under the curve (AUC) of 0.2. Conversely, injuries to the posterolateral bundle (PLB) were indicated by "Lateral Displacement + 3x Internal Rotation" (P=0.047), achieving an AUC of 0.82, sensitivity of 85%, and specificity of 75%. The utilization of 3D displacement analysis enabled precise localization and characterization of specific ligament bundles affected by injury. The agreement between arthroscopic images and MRI results was assessed using the Sherman, Lo, and Henle scales.

The application of stress MRI allows for distinguishing between injuries to individual bundles in cases of partial ACL damage. The greatest sensitivity and specificity in diagnosis were observed in the group where PLB injury was identified. This study demonstrates the potential of stress MRI with 3D displacement analysis for accurately diagnosing and characterizing partial ACL tears, thereby improving clinical management of ACL injuries.