Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, MD, USA.
Department of Orthopaedic Surgery, Medstar Union Memorial Hospital, Baltimore, MD, USA; Department of Orthopaedic Surgery and Rehabilitation, University of Iowa, Iowa City, IA, USA.
Foot Ankle Surg. 2021 Feb;27(2):201-206. doi: 10.1016/j.fas.2020.04.011. Epub 2020 Apr 30.
Optimal characterization of Adult acquired flatfoot deformity (AAFD) on two-dimensional radiograph can be challenging. Weightbearing Cone Beam CT (CBCT) may improve characterization of the three-dimensional (3D) structural details of such dynamic deformity. We compared and validated AAFD measurements between weightbearing radiograph and weightbearing CBCT images.
20 patients (20 feet, right/left: 15/5, male/female: 12/8, mean age: 52.2) with clinical diagnosis of flexible AAFD were prospectively recruited and underwent weightbearing dorsoplantar (DP) and lateral radiograph as well as weightbearing CBCT. Two foot and ankle surgeons performed AAFD measurements at parasagittal and axial planes (lateral and DP radiographs, respectively). Intra- and Inter-observer reliabilities were calculated by Intraclass correlation (ICC) and Cohen's kappa. Mean values of weightbearing radiograph and weightbearing CBCT measurements were also compared.
Except for medial-cuneiform-first-metatarsal-angle, adequate intra-observer reliability (range:0.61-0.96) was observed for weightbearing radiographic measurements. Moderate to very good interobserver reliability between weightbearing radiograph and weightbearing CBCT measurements were observed for the following measurements: Naviculocuneiform-angle (ICC:0.47), Medial-cuneiform-first-metatarsal-gapping (ICC:0.58), cuboid-to-floor-distance (ICC:0.68), calcaneal-inclination-angle(ICC:0.7), axial Talonavicular-coverage-angle(ICC:0.56), axial Talus-first-metatarsal-angle(ICC:0.62). Comparing weightbearing radiograph and weightbearing CBCT images, statistically significant differences in the mean values of parasagittal talus-first-metatarsal-angle, medial-cuneiform-first-metatarsal-angle, medial-cuneiform-to-floor-distance and navicular-to-floor-distance was observed (P < 0.05).
Moderate to very good correlation was observed between certain weightbearing radiograph and weightbearing CBCT measurements, however, significant difference was observed between a number of AAFD measurements, which suggest that 2D radiographic evaluation could potentially underestimate the severity of AAFD, when compared to 3D weightbearing CT assessment.
在二维 X 光片上对成人获得性平足畸形（AAFD）进行最佳特征描述可能具有挑战性。负重锥形束 CT（CBCT）可改善此类动态畸形的三维（3D）结构细节的特征描述。我们比较并验证了负重 X 光片和负重 CBCT 图像之间的 AAFD 测量值。
前瞻性招募了 20 名（20 只脚，右侧/左侧：15/5，男性/女性：12/8，平均年龄：52.2 岁）临床诊断为柔韧性 AAFD 的患者，他们接受了负重前后位（DP）和侧位 X 光片以及负重 CBCT 检查。两名足踝外科医生在矢状面和轴向平面（分别为侧位和 DP 射线照相）上进行 AAFD 测量。通过组内相关系数（ICC）和 Cohen's kappa 计算了内部和观察者间的可靠性。还比较了负重 X 光片和负重 CBCT 测量值的平均值。
除了内侧楔骨-第一跖骨角外，负重 X 射线测量的内部观察者可靠性（范围：0.61-0.96）均足够。负重 X 射线和负重 CBCT 测量之间的观察者间可靠性为中度至非常好，用于以下测量：楔骨-舟骨角（ICC：0.47），内侧楔骨-第一跖骨间隙（ICC：0.58），距骨-地板距离（ICC：0.68），跟骨倾斜角（ICC：0.7），轴向距骨-舟骨覆盖角（ICC：0.56），轴向距骨-第一跖骨角（ICC：0.62）。比较负重 X 光片和负重 CBCT 图像，在矢状面距骨-第一跖骨角、内侧楔骨-第一跖骨角、内侧楔骨-地面距离和舟骨-地面距离的平均值上观察到具有统计学意义的差异（P <0.05）。
在某些负重 X 射线和负重 CBCT 测量之间观察到中度至非常好的相关性，但是，在许多 AAFD 测量值之间观察到了显著差异，这表明与 3D 负重 CT 评估相比，二维 X 射线评估可能会低估 AAFD 的严重程度。
