MRI diagnosis of tears of knee anterior cruciate ligament

Objective: To investigate the value of MR imaging in diagnosis of tears of the anterior cruciate ligament(ACL) of the knee and look for methods to further improve diagnositic accuracy.Methods:Forty-four patients who had been highly suspected internal derangement of the knee was performed both MRI and arthroscopy examination.The MR images were prospectively interpreted and analyzed for accuracy of MR diagnosis of ACL tears.Result: The sensitivity,specificity,positive predictive value and negative predictive value of MR diagnosis of ACL tears were 95.7%,85.7%,88.5% and 94.7%,respectively.The PCL angle in torn ACL was(100±5.9)°,While in normal ACL(120±8.9)°(P0.05).The PCL index in torn ACL was 2.64±0.27,While in normal ACL 3.12±0.31(P0.05).Conclusion: MR imaging is an effective tool in the detection of anterior cruciate ligament tears.But the accuracy of MR imaging for diagnosis of chronic or partial tears of anterior cruciate ligament tears were decreased.The smaller of the PCL angle and the PCL index,the more possibility of ACL tears.