Assessment of the Reliability and Diagnostic Accuracy of Indirect MRI Signs for ACL Tears: Comparison with Arthroscopic Findings as the Gold Standard.

Background: The objective of this study was to evaluate the sensitivity and specificity of indirect MRI signs (PCL Angle, PCL Inclination Angle, PCL-PCA, and Anterior Drawer Sign) in diagnosing ACL tears, as confirmed by arthroscopy. Methodology: This retrospective case-control study, conducted at Shifa International Hospital in Islamabad from January to December 2023, included 100 patients divided into two groups based on arthroscopy findings: 50 with a healthy ACL (Control) and 50 with ACL deficiency (Test). MRI signs were analyzed retrospectively to calculate cut-off values, sensitivity, specificity, and AUC. Results: The study involved 100 patients (77 males, 23 females), with a mean age of 35.12 years (range 16-75). Among MRI parameters, PCL-PCA was the most sensitive (81.3%, AUC 0.821), followed by PCL angle (78.1%, AUC 0.870) and PCL inclination angle (68.8%, AUC 0.697). The Anterior Drawer Sign showed high specificity (89.19%) but lower sensitivity (57.14%) and was statistically significant (p = 0.001). Conclusion: The crux of this study is that PCL-PCA is highly sensitive in diagnosing ACL tear as an indirect and secondary parameter, followed by PCL angle, then by PCL inclination angle, and lastly by anterior drawer sign. These provided an excellent distinction between patients with and without an ACL tear.