MR evaluation of the meniscal ramp lesion in patients with anterior cruciate ligament tear

To identify the findings on magnetic resonance imaging most strongly associated with meniscal ramp lesions in patients with an anterior cruciate ligament tear. Seventy-eight consecutive patients (mean age, 33.7 years; 64 male, 14 female) with an arthroscopically proven anterior cruciate ligament tear were included in this retrospective study. The presence of the following six features on magnetic resonance images were recorded: complete fluid filling between the posterior horn of the medial meniscus and the capsule margin; edema affecting the posterior capsule; irregularity of the medial meniscus at the posterior margin; fluid at the periphery of the medial meniscus; the corner notch sign; and a vertical tear at the medial meniscus. Findings at arthroscopy served as the reference standard. Diagnostic accuracy, sensitivity, and interobserver agreement were calculated. Seven ramp lesions were noted on arthroscopy (9%). Findings of irregularity at the posterior margin (p = 0.001) and complete fluid filling between the posterior horn of the medial meniscus and the capsule margin (p = 0.004) on magnetic resonance imaging were significantly associated with the presence of a ramp lesion. With the irregularity at the posterior margin, sensitivity was 86% and specificity was 79%. Complete fluid filling sign showed sensitivity of 57% and specificity of 92%. Concordance of the two readers for the six magnetic resonance imaging features was fair to very good (k = 0.38–0.91). Irregularity at posterior margin and complete fluid filling were most sensitive findings for detecting of a ramp lesion on magnetic resonance imaging.