Department of Orthopaedic Surgery, State University of New York Downstate Health Sciences University, New York City, NY, USA.
Department of Orthopaedic Surgery, Mayo Clinic, Rochester, MN, USA.
Eur J Orthop Surg Traumatol. 2020 Aug;30(6):1061-1065. doi: 10.1007/s00590-020-02668-5. Epub 2020 Apr 18.
Percutaneous screws placed into the posterosuperior femoral neck are frequently extraosseous or "in-out-in" (IOI). These IOI screws are not readily identifiable on anteroposterior (AP) and lateral fluoroscopic images. The purpose of this study was to examine the ability of surgeons to identify IOI guide pins using sequential fluoroscopic rollover images.
A 3.2-mm guide pin was placed into the posterosuperior quadrant of eleven synthetic femur models. Five samples were "all-in" (AI), and six were IOI. Sequential fluoroscopic rollover images were obtained starting with an AP image, then images at 10-degree rollover intervals ending with a direct lateral image. Images were reviewed in a blinded fashion by five attending orthopedic trauma surgeons and 20 resident surgeons to determine whether guide pins were AI or IOI. Accuracy, interobserver reliability, sensitivity, and specificity were assessed.
The overall accuracy of responses was 86% with no difference between attending trauma surgeons and residents (p = 0.5). The sensitivity and specificity for an IOI guide pin were 98.0% and 71.2%, respectively. Interobserver reliability among surgeons was good (κ = 0.703).
The use of the sequential fluoroscopic rollover images after placement of the posterosuperior guide pin into the femoral neck was highly sensitive for detecting an IOI position. The 40-degree rollover image was the best view to evaluate the proximity of the guide pin to the posterior cortex.
经皮股骨颈后侧上方螺钉常为“外-内-外”（IOI）置钉，即螺钉穿出骨皮质。前后位（AP）和侧位透视图像上通常无法识别 IOI 螺钉。本研究旨在探讨术者通过连续透视翻转图像识别 IOI 导针的能力。
在 11 个合成股骨模型的后侧上方象限置入 3.2mm 导针。5 个样本为“全内”（AI），6 个为 IOI。首先获取 AP 位透视图像，然后每隔 10 度旋转获取透视图像，最后获取直接侧位图像，以获取连续透视翻转图像。由 5 名主治创伤骨科医生和 20 名住院医生以盲法评估图像，以确定导针是 AI 还是 IOI。评估准确性、观察者间可靠性、敏感性和特异性。
总体反应准确率为 86%，主治创伤骨科医生和住院医生之间无差异（p=0.5）。对于 IOI 导针，敏感性和特异性分别为 98.0%和 71.2%。术者之间观察者间可靠性良好（κ=0.703）。
股骨颈后侧上方导针置入后使用连续透视翻转图像高度敏感，可检测 IOI 位置。40 度翻转图像是评估导针与后皮质接近程度的最佳视图。
