Association of meniscal flounce in the knee with the pattern and location of meniscal tear, concomitant ligamentous injury, amount of knee joint effusion, and flexion and rotation angles: a magnetic resonance evaluation

Abstract

Objective To determine the association of meniscal flounce with the pattern and location of the meniscal tear, concomitant ligamentous injury, amount of knee joint effusion, and flexion and rotation angles. Materials and methods A total of 283 knees of 280 patients were retrospectively reviewed over a 9-month period. Thirty-one magnetic resonance images of patients with meniscal flounce were compared with those of age- and sex-matched control group (n = 62) without meniscal flounce. The presence of meniscal tear was evaluated and, if present, its location and pattern were recorded. The amount of joint effusion was graded, and the joint angle was measured. The Fisher’s exact, Cochran-Armitage trend, and t tests were performed to compare the findings between the two groups. The decision tree analysis was employed to determine the most significant factor of meniscal flounce. Results Meniscal flounce was present in 11.0% (31/283) of the adult population. Approximately 80.6% of meniscal flounce occurred in the torn medial menisci. The presence of meniscal flounce was significantly associated with tears at the body (p = 0.007), posterior horn (p = 0.001), and meniscocapsular junction (p = 0.002) of the medial meniscus. The decision tree analysis revealed that the posterior horn tear of the medial meniscus was the most significant predictor of meniscal flounce. Conclusion The most significant factor associated with meniscal flounce is tear at the posterior horn of the medial meniscus, followed by tear at the meniscocapsular junction.