Department of Orthopaedics and Rehabilitation, San Antonio Military Medical Center, San Antonio, TX 78234, USA.
J Orthop Trauma. 2012 Nov;26(11):643-7. doi: 10.1097/BOT.0b013e31824aed95.
To define the anatomic "safe zone" for placement of external fixator half pins into the anterior and lateral femur.
In 20 fresh-frozen hemipelvis specimens, the femoral nerve and all branches crossing the femur were dissected out to their final muscular locations. The location where the nerves crossed the anterior femur was measured from the anterior superior iliac spine and inferior margin of the lesser trochanter. The knee joint was then opened, and the distance from the superior reflection of the suprapatellar pouch to the last branch of the femoral nerve crossing the anterior femur was measured, defining the safe zone for anterior pin placement.
The last branch of the femoral nerve crossed at an average distance from the anterior superior iliac spine of 174 ± 43 mm (range, 95-248 mm) and from the lesser trochanter at a distance of 58 ± 36 mm (range, 0-136 mm). The average distance from the proximal pole of the patella to the superior reflection of the suprapatellar pouch was 46.3 ± 13.1 mm (range, 20-74 mm). Using the linear distance between the last crossing femoral nerve branch and the superior reflection of the pouch, the average safe zone measured 199 ± 39.8 mm (range, 124-268 mm). The safe zone correlated with thigh length (r = 0.48, P = 0.03). All nerve branches terminated at their muscular origins without crossing lateral to a line from the anterior greater trochanter to the anterior aspect of the lateral femoral condyle.
The safe zone for anterior external fixator half pin placement into the femur is on average 20 cm in length and can be as narrow as 12 cm. Anterior pins should begin 7.5 cm above the superior pole of the patella to avoid inadvertent knee joint penetration. Because the entire lateral femur is safely available for half pin placement, including distally, we recommend the use of alternative frame constructs with either anterolateral or lateral pins given the limitations and risks of anterior pin placement.
确定在股骨前侧和外侧置入外固定架半针的解剖“安全区”。
在 20 个新鲜冷冻的半骨盆标本中，将股神经及其所有穿过股骨的分支解剖至其最终的肌内位置。测量神经穿过股骨前侧的位置距髂前上棘和小转子下边缘的距离。然后打开膝关节，测量髌上囊的上反射点到穿过股骨前侧的股神经最后分支的距离，定义前侧针放置的安全区。
股神经的最后分支穿过髂前上棘的平均距离为 174 ± 43 mm（范围，95-248 mm），穿过小转子的距离为 58 ± 36 mm（范围，0-136 mm）。髌骨近端至髌上囊上反射点的平均距离为 46.3 ± 13.1 mm（范围，20-74 mm）。使用最后一个穿过股神经分支和囊上反射点之间的直线距离，平均安全区测量值为 199 ± 39.8 mm（范围，124-268 mm）。安全区与大腿长度相关（r = 0.48，P = 0.03）。所有神经分支都在其肌肉起点终止，而不会穿过从前大转子到外侧股骨髁前侧的线。
股骨前侧外固定架半针放置的安全区平均长度为 20 cm，最短可达 12 cm。前针应从髌骨上极上方 7.5 cm 开始，以避免意外穿透膝关节。由于整个股骨外侧都可安全用于半针放置，包括远端，因此我们建议使用替代框架结构，使用前外侧或外侧针，因为前侧针放置存在限制和风险。
