Accuracy of MRI Scanning for the Diagnosis of Meniscus Tears Associated with Knee Osteoarthritis

Objective: To assess the validity of magnetic resonance imaging for the identification of meniscus tears related to knee osteoarthritis by taking arthroscopy as a reference standard. Methodology: From August 2018 to August 2021, cross-validation research was conducted in the radiology department of Memon Medical Institute Hospital Karachi. A total of 147 patients with knee joint pain were selected and referred to MRI knee. MRI knee without contrast including proton density (PD) and fat saturation (Fat Sat) sequences was performed. The absence of an intrameniscal high signal was considered evidence of a normal meniscus. Grade 1 and grade 2 meniscal degeneration were considered positive if an intrameniscal high signal was present but did not advance toward the articular surface, but grade 3 meniscus tears were considered positive if an intrameniscal high signal intensity reached the articular surface. All patients were then assessed by arthroscopy. MRI results were compared with arthroscopic results in every patient. Data regarding age, gender, site, type and grade of tear with the final diagnosis were noted on proforma. SPSS version 25 was used to analyse the data. Results: For MRI, the sensitivity was assessed to be 82.7%, the specificity to be 93%, the positive predictive value to be 93.5%, the negative predictive value to be 81.6%, and the accuracy to be an estimated 87.4%. For lateral meniscus tears, the sensitivity and specificity of MRI were 90% and 100%. The sensitivity and specificity of MRI in evaluating medial meniscus tears were 84% and 95%, respectively. However, the sensitivity and specificity of MRI for the detection of bilateral meniscal lesions were low such as 60% and 67%. Conclusion: MRI can be utilized as a diagnostic modality for meniscus tears. Furthermore, pre-operative MRI is accurate to diagnose lateral and medial meniscal tears. However, it is not highly accurate in bilateral meniscal tears.