Magnetic Resonance Imaging is an Effective First-Line Non-invasive Tool for Meniscal Tear Detection: A Retrospective Comparative Analysis with Knee Arthroscopy

PurposeThe purpose of this study is to evaluate and compare the diagnostic accuracy of MRI imaging to knee arthroscopic intra-operative findings for identifying or diagnosing meniscal tears.MethodsA retrospective study was conducted in a single university hospital on patients who underwent MRI and knee arthroscopy, showing either medial meniscus or lateral meniscus tears were included in the study. The pre-operative MRI findings of patients were compared to intra-operative arthroscopic findings to determine the presence, location, and morphology of meniscus tears. The results of arthroscopy were considered as the definitive diagnosis.ResultsA total of 543 patients were initially identified. Of these, 220 met the study eligibility criteria and were included. Sensitivity, specificity, and accuracy of MRI in relation to arthroscopy for medial meniscus tears were 94.29% (95% CI [89.05% to 97.50%]), 78.75% (95% CI [68.17% to 87.11%]), and 88.64% (95% CI [83.68% – 92.51%]), respectively, and 76.74% (95% CI [66.39% – 85.18%]), 94.03% (95% CI [88.58% – 97.39%]), and 87.27% (95% CI [82.13% – 91.37%]) for lateral meniscus tears respectively. Complex tears were the most common morphology of tears, and posterior horn tears were the most common location.ConclusionsMRI is an effective first-line non-invasive diagnostic tool for investigating meniscus tears, with overall diagnostic accuracies of 88.64% for MM tears and 87.27% for LM tears. MM tears had the highest incidence, particularly in the posterior horn. MRI demonstrated high sensitivity for MM tears, high specificity for LM tears, and substantial agreement with arthroscopy in diagnosing both MM and LM tears. However, MRI's specificity for MM tears and sensitivity for LM tears was lower, suggesting that it may not be as reliable in confirming MM tears or ruling out LM tears.Level of EvidenceLevel III, retrospective cohort study.