Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan.
Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan.
Bone. 2019 Oct;127:620-625. doi: 10.1016/j.bone.2019.07.025. Epub 2019 Jul 31.
High-resolution peripheral quantitative computed tomography (HR-pQCT) has enabled us to observe changes of bone microstructure during fracture healing. However, a method of analyzing the healing process after osteosynthesis has yet to be established due to implant artifacts. The purpose of this study was to investigate the effects of volar locking plates for distal radius fractures on the image quality of HR-pQCT.
Four different types of plates for distal radius fractures were evaluated. The scan region of HR-pQCT was the center of each plate, not including the screw insertion sites. To assess plate-generated noise, each plate was fixed to the top of a water-filled rubber glove, scanned by HR-pQCT, and the signal-to-noise ratio (SNR) of the region under the plates was calculated. To investigate accuracy, 12 cadaveric radii with and without each plate were scanned by HR-pQCT, and differences between the measured values with and without the plate were evaluated. Differences between the measurements of the entire circumference and of the dorsal third of the radius were also compared. Reproducibility of the in vivo measurement was investigated by repeated scans of 10 patients with distal radius fractures who had undergone surgery with a volar locking plate.
The SNR was significantly higher away from the plate than immediately below the plate. Percentage differences of the measurement values between with and without the plate were 1.4%-3.2% for cortical bone mineral density (Ct.BMD) and 7.2%-9.8% for cortical bone thickness (Ct.Th) when the entire circumference was measured. When the dorsal third was measured, they were 0.3%-1.7% for Ct.BMD and 1.8%-2.7% for Ct.Th. The root-mean-square coefficient of variation (RMS%CV) was 1.12% for Ct.BMD and 4.18% for Ct.Th.
The accuracy and reproducibility of cortical bone measurements with a volar locking plate on HR-pQCT were acceptable when the dorsal third of the Ct.BMD was analyzed, and this method would be useful for in vivo analysis of the fracture healing process after osteosynthesis.
高分辨率外周定量计算机断层扫描（HR-pQCT）使我们能够观察到骨折愈合过程中骨微观结构的变化。然而，由于植入物伪影的存在，尚未建立分析接骨后愈合过程的方法。本研究旨在探讨掌侧锁定板治疗桡骨远端骨折对 HR-pQCT 图像质量的影响。
评估了四种不同类型的桡骨远端骨折接骨板。HR-pQCT 的扫描区域为每个接骨板的中心，不包括螺钉插入部位。为了评估接骨板产生的噪声，将每个接骨板固定在充满水的橡胶手套顶部，通过 HR-pQCT 扫描，并计算接骨板下方区域的信噪比（SNR）。为了研究准确性，用 HR-pQCT 扫描了 12 个带有和不带每种接骨板的尸体桡骨，并评估了有和无接骨板时测量值的差异。还比较了整个圆周和桡骨背三分之一的测量值之间的差异。通过对 10 名接受掌侧锁定板手术的桡骨远端骨折患者进行重复扫描，研究了体内测量的可重复性。
SNR 明显高于接骨板下方的位置。当测量整个圆周时，皮质骨骨密度（Ct.BMD）和皮质骨厚度（Ct.Th）的有板和无板测量值之间的百分比差异分别为 1.4%-3.2%和 7.2%-9.8%。当测量桡骨背三分之一时，它们分别为 0.3%-1.7%的 Ct.BMD 和 1.8%-2.7%的 Ct.Th。Ct.BMD 的均方根变异系数（RMS%CV）为 1.12%，Ct.Th 的 RMS%CV 为 4.18%。
当分析桡骨背三分之一的皮质骨 BMD 时，掌侧锁定板 HR-pQCT 皮质骨测量的准确性和可重复性是可以接受的，这种方法将有助于接骨后骨折愈合过程的体内分析。
