股骨干骨折闭合复位髓内钉内固定术中利用小粗隆-股骨干切线控制股骨旋转

Tangent of lesser trochanter and femoral shaft for intraoperative control of rotation of femoral fractures

目的探讨闭合复位髓内钉内固定治疗股骨干骨折术中利用股骨小粗隆-股骨干切线控制股骨旋转的可行性及准确性。方法选择志愿者20名,行CT扫描并分别测量两侧股骨小粗隆-股骨干切线与股骨后髁连线夹角,并比较两侧股骨该夹角的差异。采用C型臂X线机对20具股骨标本于截骨前后分别测量股骨小粗隆-股骨干切线与股骨后髁连线夹角及股骨颈前倾角,比较2种方法的测量结果。结果志愿者左侧股骨小粗隆-股骨干切线与股骨后髁连线夹角为（65.9±7.5）°,右侧为（64.9±7.2）°;两侧间差值为1.2°～8.7°（3.9±2.2）°,差异无统计学意义（t=0.927,P=0.365）。20具股骨标本股骨小粗隆-股骨干切线与股骨后髁连线夹角为50.5°～80.0°（65.7±8.0）°,股骨颈前倾角为9.0°～19.5°（9.0±8.4）°。股骨小粗隆-股骨干切线法残留旋转移位为1.0°～7.0°（3.7±1.9）°,股骨颈前倾角法残留旋转移位为1.0°～8.5°（4.4±2.1）°,二者间差异无统计学意义（t=1.113,P=0.279）。结论股骨小粗隆-股骨干切线法依靠确切的测量点来测量,准确性较高;此外,旋转程度可以量化,便于矫正;无需特殊投照体位,简便易行。

Objective To investigate a new method for femoral rotational alignment during intramedullary nail insertion using the profile of the lesser trochanter and its relation to the femoral shaft. Methods CT scan was applied in 20 volunteers. The tangent of the lesser trochanter-femoral shaft and the posterior femoral condyles were measured on both lower extremities and the difference between the 2 sides was evaluated. Before and after osteotomy, the tangent of the lesser trochanter-femoral shaft（method I）, the anteversion of femoral neck（method II） and the posterior femoral condyles were measured on 20 dried human femora using a standard image intensifier. Results The side difference of the angles of the tangent of the lesser trochanterfemoral shaft and the posterior femoral condyles was（3.9±2.2）°（range, 1.2°-8.7°）, and no difference was found between 2 sides（t =0.927,P =0.365）. These two methods showed malrotation of（3.7 ±1.9）° and（4.4±2.1）°, respectively, and no difference was found between 2 methods（t =1.113,P =0.279）. Conclusion Our method is simple to execute because it depends on a definite point of measurement. Furthermore, an angle is recorded for each extremity, which enables us to estimate the amount of the rotational difference. This method does not depend on special views, especially at the hip, but only on a direct anteroposterior view with gradual internal rotation of the image intensifier.