Department of Orthopaedic Surgery, The Johns Hopkins University, Baltimore, MD.
J Pediatr Orthop. 2022 Sep 1;42(8):e847-e851. doi: 10.1097/BPO.0000000000002208. Epub 2022 Jul 13.
Displaced pediatric tibial tubercle fractures are commonly stabilized with screws directed posteriorly toward neurovascular structures. Here, we (1) characterize the variation of the popliteal artery among pediatric patients; and (2) recommend a safe screw trajectory for fixation of tibial tubercle fractures.
We retrospectively identified 42 patients (42 knees; 29 female) aged 12-17 years with lower-extremity magnetic resonance imaging (MRI) at a tertiary academic center. The mean patient age was 14.5 (range: 12-17) years, and the mean body mass index value was 19.1 (range: 14.9-25.1). We included patients with open physes or visible physeal scars and excluded those with prior instrumentation or lower-extremity injury. Using sagittal MRI, we measured the distances from 5 levels each on the anterior and posterior tibial cortex to the popliteal artery (level 1, midpoint of proximal tibial epiphysis; level 2, the proximal extent of the tubercle; level 3, tubercle prominence; level 4, 2 cm distal to the proximal extent of the tubercle; level 5, 4 cm distal to the proximal extent of the tubercle). Using coronal MRI, we measured the width of the tibia at each level and the distance from the lateral-most and medial-most cortex to the artery.
The popliteal artery was laterally positioned in all knees. The mean distance between the artery and lateral-most aspect of the tibia at each level ranged from 1.9 to 2.4 cm, and from 2.3 to 3.9 cm from the medial-most aspect of the tibia. The mean distance that a screw can advance before vascular injury was 5.1 cm at level 1. The shortest mean distance to the popliteal artery was 1.7 cm, at level 5. There is minimal distance between the posterior tibial cortex and the artery at all levels.
Understanding the position of the popliteal artery in pediatric patients can help when stabilizing tibial tubercle fractures. Because the artery is close to the posterior cortex, a drill exiting in line with the popliteal artery risks vascular injury. Therefore, we recommend that screws exit within the medial 60% of the tibia.
IV.
儿童胫骨结节移位骨折通常通过向后朝向神经血管结构的螺钉固定。在这里，我们（1）描述了儿童患者中腘动脉的变化；（2）为胫骨结节骨折的固定推荐了一种安全的螺钉轨迹。
我们回顾性地在一家三级学术中心确定了 42 名（42 膝；29 名女性）年龄在 12-17 岁的下肢磁共振成像（MRI）患者。患者平均年龄为 14.5（范围：12-17）岁，平均体重指数值为 19.1（范围：14.9-25.1）。我们纳入了干骺端开放或可见骺线瘢痕的患者，并排除了有既往内固定或下肢损伤的患者。我们使用矢状面 MRI 测量了胫骨前、后皮质上 5 个水平距腘动脉的距离（水平 1：胫骨近端骨骺的中点；水平 2：结节的近端范围；水平 3：结节突出；水平 4：结节近端 2cm 处；水平 5：结节近端 4cm 处）。我们使用冠状面 MRI 测量了每个水平的胫骨宽度以及距动脉最外侧和最内侧皮质的距离。
所有膝关节的腘动脉均位于外侧。在每个水平上，动脉与胫骨最外侧之间的平均距离范围为 1.9 至 2.4cm，与胫骨最内侧之间的平均距离为 2.3 至 3.9cm。在水平 1 处，血管损伤前螺钉可前进的平均距离为 5.1cm。距离腘动脉最近的平均距离为 1.7cm，位于水平 5。所有水平的胫骨后皮质与动脉之间的距离都很小。
了解儿童患者腘动脉的位置有助于稳定胫骨结节骨折。由于动脉靠近后皮质，与腘动脉成一直线的钻头可能会损伤血管。因此，我们建议螺钉在胫骨的内侧 60%范围内穿出。
IV。
