MRI evaluation of the posterior meniscus root tear / 中华放射学杂志

ABSTRACT

Objective To determine the value of MRI for diagnosing the posterior meniscus root tear. Methods MR examinations of 30 patients with tear of the posterior meniscus root confirmed by knee arthroscopies were retrospectively reviewed. Of the 30 patients, 17 with posterior medial meniscus root tear (MMRT) and 13 with posterior lateral meniscus root tear (LMRT). The diagnostic sensitivity of MRI for the posterior meniscus root tear was analyzed. Fisher's exact test was used to compare the detection rate of MRI for MMRT with that for LMRT. Results All 17 cases with MMRT and 9 cases out of 13 with LMRT were correctly diagnosed by MRI and the diagnostic sensitivity of MRI for the posterior meniscus root tear was 86. 7% (26/30). The main MR appearance of the posterior meniscus root tear was distortion of the meniscal root, with its low signal replaced by abnormal high signal. The detection rate of MRI for MMRT (17/17)was significantly greater than that for LMRT (9/13) ( P =0. 026). The prevalence of MMRT associated with meniscus extrusion ( 15/17 ) was significantly greater than that of LM RT ( 6/13 ) ( P = 0. 020), but the prevalence of MMRT associated with anterior cruciate ligament (ACL) injury (5/17) was significantly lower than that of LMRT (11/13) (P = 0. 004). Conclusion MRI is a relatively good method for detection of posterior meniscus root tears and associated injuries.