Department of Orthopaedic Surgery, Hiratsuka City Hospital, Hiratsuka, Japan.
Arthroscopy. 2011 Aug;27(8):1071-8. doi: 10.1016/j.arthro.2011.02.029. Epub 2011 Jun 11.
To compare the arc of rotation of the knee joint at 90° of flexion in control knee joints and those affected by recurrent subluxation of the lateral meniscus (RSLM), in determining whether rotatory instability of the knee joint is a risk factor for RSLM.
Knee joints were diagnosed with RSLM when there was a history of mechanical locking episodes and when subluxation of the lateral meniscus with the peripheral margin of the posterior segment moving anteriorly beyond the lateral femoral condyle was recognized on arthroscopy. In this study 288 knee joints in 270 subjects were evaluated. The joints were classified into a control group (252 joints), an RSLM group (24 joints), and a contralateral RSLM group (12 joints). The arcs of external and internal rotation at 90° of flexion of the knee joint induced by 7 Nm of torque under non-weight-bearing conditions were measured with a Biodex System 3 (Biodex Medical Systems, Shirley, NY).
There were no significant differences in mean values of external rotation among the 3 groups. The mean values of internal rotation of both the RSLM and contralateral RSLM groups were significantly larger than that of the control group, by about 15° (P < .0001). The mean value of internal rotation was slightly higher than that of external rotation in the RSLM and contralateral RSLM groups, although the mean value of internal rotation was smaller than that of external rotation by 10.1° in the control group.
RSLM was found to be strongly related to bilateral increase in the arc of internal rotation at 90° of flexion of the knee joint, suggesting that internal rotatory instability of the flexed knee joint can be considered one of the risk factors for and diagnostic parameters of RSLM.
Level III, diagnostic study of nonconsecutive patients.
比较膝关节 90°屈曲时正常膝关节和复发性外侧半月板半脱位（RSLM）膝关节的旋转弧，以确定膝关节旋转不稳定是否是 RSLM 的危险因素。
当膝关节存在机械性锁定发作史且关节镜下发现外侧半月板后段外侧缘向前外侧越过外侧股骨髁发生半脱位时，诊断为 RSLM。本研究共评估了 270 名受试者的 288 个膝关节。将膝关节分为对照组（252 个膝关节）、RSLM 组（24 个膝关节）和对侧 RSLM 组（12 个膝关节）。在非负重条件下，用 Biodex 系统 3（Biodex Medical Systems，Shirley，NY）测量膝关节 90°屈曲时 7 Nm 扭矩引起的膝关节外旋和内旋弧。
3 组间膝关节外旋平均值无显著差异。RSLM 组和对侧 RSLM 组的膝关节内旋平均值均明显大于对照组，约 15°（P<0.0001）。RSLM 组和对侧 RSLM 组的内旋平均值略高于外旋平均值，而对照组的内旋平均值比外旋平均值小 10.1°。
RSLM 与膝关节 90°屈曲时内旋弧的双侧增加密切相关，提示膝关节屈曲时的内旋不稳定可被视为 RSLM 的危险因素之一和诊断参数之一。
III 级，非连续患者的诊断研究。
