Department of Orthopedic Sports Medicine, Hoshigaoka Kosei Nenkin Hospital, 4-8-1 Hoshigaoka Hirakata, Osaka, 573-8511, Japan.
Knee Surg Sports Traumatol Arthrosc. 2013 Mar;21(3):736-9. doi: 10.1007/s00167-012-2078-3. Epub 2012 Jun 9.
To compare magnetic resonance (MR) signal intensity in the medial meniscus at the time of displacement and after its reduction in patients with a displaced bucket-handle tear of the meniscus associated with anterior cruciate ligament (ACL) injury.
Nine chronic ACL-deficient patients (3 male, 6 female, mean age 29 years) with locking due to a displaced fragment of the medial meniscus following a bucket-handle tear were involved in this study. In all patients, the following two-stage surgeries were planned as follows: first operation, arthroscopic reduction of the meniscus; second operation, meniscal repair and ACL reconstruction after immobilization for 1-2 weeks. Magnetic resonance imaging (MRI) evaluation using coronal T2*-weighted images was performed when the knee was locked and after the meniscus was reduced. Signal intensity before and after meniscal reduction was compared in the same patients.
In 8 of the 9 patients, the displaced fragment exhibited high signal intensity in 1 patient and mildly high in 7 patients. After its reduction, the signal intensity changed to low in all 8 patients.
A high-intensity signal in the displaced fragment of the medial meniscus may change to low after its reduction to its original position. Therefore, at the time of decision-making regarding meniscus repair for a displaced meniscus in a locked knee, surgeons should give priority to arthroscopic findings rather than to signal intensity on MRI.
Diagnostic study, Level III.
比较伴有前交叉韧带（ACL）损伤的半月板桶柄状撕裂患者半月板内移时和复位后的磁共振（MR）信号强度。
本研究纳入了 9 例慢性 ACL 缺失患者（3 名男性，6 名女性，平均年龄 29 岁），这些患者因半月板内侧桶柄状撕裂所致的半月板内移块发生交锁。所有患者均计划行两阶段手术：第一次手术为半月板镜下复位；第二次手术为半月板修复和 ACL 重建，在固定 1-2 周后进行。当膝关节交锁和半月板复位后，使用冠状 T2*-加权图像进行 MRI 评估。在同一患者中比较半月板复位前后的信号强度。
在 9 例患者中，8 例移位的半月板内移块表现为高强度信号，1 例为轻度高强度信号。复位后，8 例患者的信号强度均变为低强度。
半月板内移块的高强度信号在复位至原始位置后可能变为低强度。因此，在决定对锁定膝关节中的半月板进行修复时，外科医生应优先考虑关节镜检查结果，而不是 MRI 上的信号强度。
诊断研究，III 级。
