膝关节半月板后根部撕裂的MRI评价

目的 探讨MRI对膝关节半月板后根部撕裂的价值.方法 回顾分析经关节镜证实的30例半月板后根部撕裂患者(17例累及内侧半月板,13例累及外侧半月板)的MRI表现,分析MRI对半月板后根部撕裂的诊断敏感度,MRI对内侧、外侧半月板后根部撕裂的检出比例比较采用Fisher确切概率法检验.结果 30例半月板后根部撕裂患者中,MRI正确诊断26例(包括17例内侧半月板后根部撕裂和9例外侧半月板后根部撕裂),诊断敏感度为86.7%(26/30).半月板后根部撕裂的MRI表现主要为后根部形态失常,代之以异常高信号影.MRI对内侧半月板后根部撕裂的检出比例(17/17)明显高于外侧(9/13)(P=0.026).内侧半月板后根部撕裂合并半月板脱位的发生比例(15/17)明显高于外侧(6/13)(P=0.020),但并发前交叉韧带损伤的发生比例(5/17)则明显低于外侧(11/13)(P=0.004).结论 MRI是诊断半月板后根部撕裂及伴发损伤的较好方法.

MRI evaluation of the posterior meniscus root tear

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.