Tibial Plateau Cysts at the Meniscal Root Insertions: Incidence and Association

Background: The purpose of this study is to identify a possible relationship between high T2-signal cyst-like foci in the tibial plateau at the meniscal root insertions and meniscal pathology. Methods: Institutional review board approval was obtained for this retrospective study. HIPAA compliance was maintained throughout this study. Two radiologists reviewed 200 knee MRI examinations for tibial plateau cysts at the meniscal root insertion sites; meniscal tears and intrameniscal cysts were also noted. The knee MRI examinations were also evaluated for articular cartilage abnormalities of the medial and lateral tibial plateaus. Results: Of the 200 knee examinations, 83(41.5%) demonstrated medial meniscal pathology and 47(23.5%) demonstrated lateral meniscal pathology. Twenty (10%) demonstrated cysts in at least one of the described locations; two knees had cysts in two separate locations. four (2%) examinations had cysts at the anterior horn medial meniscal insertion, and all four (100%) had medial meniscal pathology (p = 0.028). Eleven (5.5%) examinations demonstrated cysts at the posterior horn medial meniscal insertion, and eight (72.7%) had medial meniscal pathology (p = 0.031). five (2.5%) examinations demonstrated cysts at the anterior horn lateral meniscal insertion, and one (20%) had lateral meniscal pathology (p = 0.374). Two (1%) examinations demonstrated cysts at the posterior horn lateral meniscal insertion, and one (50%) had lateral meniscal pathology (p = 0.852). Conclusions: Cysts at the meniscal insertions are often seen on knee MRI. Cysts located at the insertions of the medial meniscus have a statistically significant association with meniscal pathology. Level of evidence: Level II, retrospective study with development of diagnostic criteria on the basis of consecutive patients.