MRI versus clinical examination for the diagnosis of meniscal and ligamentous injuries of knee

Objective: The purpose of this study was to correlate clinical and MRI findings in diagnosing ligament and meniscus tears in knee joint injuries. Material and methods: 30 cases with history of rotational injury having knee pain and recurrent swelling were subjected to study. The age range of 11-60 years who were referred to Radiology Department for MRI of knee joint following injury to the knee was included. Prior to MRI, a detailed history, clinical, and local examination was done in all the subjects. MRI was carried out on 1.5 Tesla MR Machine and the standard protocol consisted of fat-suppressed PD (TE 45, TR 2800) in axial, sagittal, and coronal planes, T2W (TE 80, TR 4000) in sagittal plane and T1W (TE 11, TR 495) in sagittal plane. Results: MRI had 100% sensitivity and negative predictive value (NPV) of diagnosing ACL tears in this study. Clinical examination had sensitivity of 88% and NPV 75% in diagnosing ACL injuries as compared to arthroscopy. There was high NPV of MR examination (96%) in diagnosing meniscus tear while the PPV of MR examination was low (71%) as compared to arthroscopy. These values were low in case of clinical examination. Conclusion: Magnetic resonance imaging is useful as a pre operative diagnostic tool in selected cases where a clinical examination cannot be performed as in acute injuries or in cases where clinical examination is inconclusive. The efficacy of MRI in diagnosing a tear varies among different intra articular structures. MRI has a high accuracy in diagnosing a tear of PCL. Sensitivity for medial meniscal tear is higher as compared to lateral meniscus and high for PCL as compared to ACL. MRI has a high positive predictive value for ACL, but has a low negative predictive value. For PCL tears, MRI has a high negative predictive value which indicates that with a negative result for PCL on MRI, a diagnostic arthroscopy can be avoided.