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

OBJECTIVE: To identify the findings on magnetic resonance imaging most strongly associated with meniscal ramp lesions in patients with an anterior cruciate ligament tear.

SUBJECTS AND METHODS: 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.

RESULTS: 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).

CONCLUSIONS: Irregularity at posterior margin and complete fluid filling were most sensitive findings for detecting of a ramp lesion on magnetic resonance imaging.