Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois.
School of Medicine, University of Wisconsin, Madison, Wisconsin.
J Bone Joint Surg Am. 2022 May 18;104(10):889-895. doi: 10.2106/JBJS.21.00959. Epub 2022 Feb 15.
The purpose of the present study was to determine specific fluoroscopic views of the femoral neck to accurately identify partially extraosseous ("in-out-in"; IOI) placement of the posterosuperior screw for fixation of femoral neck fractures.
A 3.2-mm guide pin was placed in the posterosuperior aspect of 2 synthetic femur models: 1 entirely intraosseous and 1 IOI. Sequential fluoroscopic images were made at 5° intervals in order to identify which fluoroscopic projections identified IOI guide pin placement. These images were utilized to inform screw placement and assessment in the second phase of the study, which involved the use of cadaveric specimens. In Phase II, the posterosuperior screw of the inverted triangle was placed in 10 cadaveric specimens with use of a standard posteroanterior fluoroscopic view and 1 of 2 lateral views, either (1) neck in line with the shaft, i.e., 0° lateral; or (2) a -15° rollunder view. The final fluoroscopic views (i.e., the posteroanterior and multiple lateral and oblique views) were randomized and blinded for review by 10 orthopaedic residents and 5 attending orthopaedic traumatologists. Specimens were stripped of soft tissue and inspected for screw perforation.
Overall accuracy of respondents was 68.8%, with no difference between the attending traumatologists (71.8%) and resident surgeons (67.4%; p = 0.173). Interobserver reliability was moderate (κ = 0.496). Dissection identified that 4 (40%) of 10 screws were extraosseous. All of the extraosseous screws were placed with use of the 0° lateral view. The -15° rollunder lateral view was the most sensitive (81.7%) and specific (92.2%) view for identifying IOI screw placement.
Surgeons often utilize the standard posteroanterior and 0° lateral fluoroscopic views to safely place screws; however, many of these screws are IOI. The addition of a -15° rollunder lateral view significantly improved identification of IOI screws in the posterosuperior femoral neck. Unidentified IOI screw placement may result in damage to the blood supply of the femoral head.
本研究的目的是确定股骨颈的特定透视视图，以准确识别后上螺钉固定股骨颈骨折的部分骨外（“进-出-进”；IOI）放置。
将 3.2 毫米导针放置在 2 个合成股骨模型的后上侧：1 个完全在骨内，1 个 IOI。以 5°的间隔连续拍摄透视图像，以确定哪些透视投影可识别 IOI 导针的放置。这些图像用于指导第二阶段研究中的螺钉放置和评估，该研究涉及使用尸体标本。在第二阶段，使用标准前后位透视视图和 2 种侧位视图中的 1 种（1）颈与干成一直线，即 0°侧位；或（2）-15°下滚视图，将倒三角的后上螺钉放置在 10 个尸体标本中。最后将透视视图（即前后位和多个侧位和斜位视图）随机化并对 10 名骨科住院医师和 5 名主治骨科创伤医师进行盲法审查。将标本剥离软组织并检查螺钉穿孔。
总体而言，受访者的准确率为 68.8%，主治创伤医师（71.8%）和住院医师之间无差异（67.4%；p=0.173）。观察者间可靠性为中等（κ=0.496）。解剖发现，10 个螺钉中有 4 个（40%）为骨外螺钉。所有骨外螺钉均使用 0°侧位视图放置。-15°下滚侧位视图是识别 IOI 螺钉放置最敏感（81.7%）和最特异（92.2%）的视图。
外科医生通常使用标准的前后位和 0°侧位透视视图来安全放置螺钉；然而，许多这些螺钉是 IOI。增加-15°下滚侧位视图可显著提高后上股骨颈 IOI 螺钉的识别率。未识别的 IOI 螺钉放置可能导致股骨头血供受损。
