Department of Orthopaedic Surgery and Traumatology, Kantonsspital St. Gallen, Rorschacherstrasse 95, 9007, St. Gallen, Switzerland.
Arch Orthop Trauma Surg. 2023 Aug;143(8):5085-5093. doi: 10.1007/s00402-023-04901-2. Epub 2023 May 12.
Accurate radiographic assessment of proximal humeral fractures (PHF) is important as it influences clinical decision-making and predicts clinical outcome. Since aberrant radiographic views might influence the assessment of fracture displacement, it was the goal of this study to investigate the impact of aberrant beam paths on radiographic assessment of PHF.
Ten consecutive patients with a displaced PHF, bilateral computed tomography (CT) scan, and a true clinical AP radiograph were included. Digitally reconstructed radiographs (DRRs) were generated and aberrant beam paths were simulated by rotation of ± 30° around the horizontal (flexion and extension) and vertical axis (internal and external rotation) by increments of 10°. Measurement of the neck-shaft-angle (NSA) and eccentric head index (EHI) addressed humeral angulation and offset, respectively. Paired comparisons determined the influence of aberrant beam paths on both measurements between incremental altered views, and between clinical and digital true AP views. Descriptive statistics assessed the change in Neer classification and recommended treatment.
True AP DRRs approximated the clinical true AP view by a mean difference of 2° for NSA, and a mean difference of 0.12 for EHI. NSA in injured shoulders was most susceptible to malrotation around the vertical axis (p < 0.03), with largest differences seen for internal rotation. Aberrant projections in extension had no influence on NSA (p > 0.70), whereas flexion of ≥ 20° and 30° demonstrated differences in injured and uninjured shoulders, respectively (p < 0.05). EHI was only influenced by malrotation in internal rotation in uninjured shoulders (p < 0.03). Alterations in Neer type occurred at 30° of malrotation in 5 cases, with a change in recommended treatment in 2.
Humeral angulation and offset measurements on AP radiographs are more susceptible to aberrant beam paths in fractured humeri. Altered radiographic beam paths around the vertical axis showed the most substantial influence on the assessment of PHF, with angular measurements demonstrating larger differences then offset measurements. Beam path alterations of 30° can influence the Neer classification, and might influence fracture displacement-based decisions.
准确的肱骨近端骨折（PHF）的放射学评估很重要，因为它会影响临床决策并预测临床结果。由于异常的射线照相视图可能会影响骨折移位的评估，因此本研究的目的是研究异常射线束路径对 PHF 放射学评估的影响。
连续纳入 10 例移位的 PHF 患者，双侧计算机断层扫描（CT）扫描和真实的临床 AP 射线照相。生成数字重建射线照相（DRR），通过围绕水平轴（屈曲和伸展）和垂直轴（内旋和外旋）以 10°的增量旋转±30°模拟异常射线束路径。颈干角（NSA）和偏心头指数（EHI）的测量分别用于评估肱骨头的角度和偏移。配对比较确定了在增量改变的视图之间以及在临床和数字真实 AP 视图之间异常射线束路径对这两个测量值的影响。描述性统计评估了 Neer 分类的变化和推荐的治疗方法。
真实 AP DRR 与 NSA 的临床真实 AP 视图相差 2°，EHI 的平均差值为 0.12。受伤肩部的 NSA 最容易受到围绕垂直轴的旋转（p <0.03），内旋时差异最大。在伸展时异常投影对 NSA 没有影响（p >0.70），而屈曲≥20°和 30°分别显示受伤和未受伤肩部的差异（p <0.05）。EHI 仅在未受伤的肩部中受到内旋时的旋转不良的影响（p <0.03）。在 5 例中，在 30°的旋转不良时出现 Neer 类型的改变，有 2 例改变了推荐的治疗方法。
在骨折肱骨头中，AP 射线照相上的肱骨角度和偏移测量更容易受到异常射线束路径的影响。围绕垂直轴的异常射线照相束路径对 PHF 的评估影响最大，角度测量的差异大于偏移测量。30°的射线束路径改变可能会影响 Neer 分类，并可能影响基于骨折移位的决策。
