Significance of the arthroscopic meniscal flounce sign: a prospective study.

Background: The meniscal flounce sign is a fold in the free, nonanchored inner edge of the medial meniscus that can be noted during routine arthroscopy of the knee.

Hypothesis: The meniscal flounce sign can be a significant indicator of the presence or absence of medial meniscus injury.

Study Design: Cohort study (diagnosis); Level of evidence, 4.

Methods: One hundred sixty-eight patients were prospectively evaluated at the time of the arthroscopy for the presence or absence of the arthroscopic meniscal flounce sign. These results were then correlated with the presence of medial meniscus tears.

Results: The presence of the meniscal flounce sign has a positive predictive value of a normal meniscus of 0.97 (63/65). The absence of the meniscal flounce sign has a positive predictive value of an abnormal meniscus of 0.98 (101/103). Specificity is 98%, and sensitivity is 97%.

Conclusion: The absence of the arthroscopic meniscal flounce sign is a sensitive and specific predictor of the presence of medial meniscus tears that should alert the surgeon to probe carefully for an occult medial meniscus tear.