Foot and Ankle Clinic, Universidade Federal de São Paulo, Rua Sena Madureira, 1500, Vila Clementino, São Paulo, 04021-001, Brazil.
Department of Diagnostic Imaging, Universidade Federal de São Paulo, São Paulo, Brazil.
AJR Am J Roentgenol. 2021 Jan;216(1):132-140. doi: 10.2214/AJR.19.22563. Epub 2020 Nov 25.
The purpose of this study was to determine whether the relative length of protrusion of the second metatarsal, measured on MRI and weight-bearing foot radiography, predicts the diagnosis of second metatarsophalangeal (MTP) joint plantar plate (PP) tear on MRI. We retrospectively evaluated 166 consecutive patients (211 feet). Patients had undergone weight-bearing foot radiography and forefoot MRI. Using the Coughlin method, two independent observers measured second meta-tarsal protrusion length on radiography and MRI. MRI findings were classified as normal PP, complete PP tear, or degenerative or partial PP tear. Patients had a mean age of 47 ± 14.6 (SD) years, and 131 (78.9%) were women. MRI measurements were highly correlated with radiographic measurements ( = 0.882; 95% CI, 0.866-0.898; < 0.001). A significant correlation was found between length of protrusion and cases classified as either normal PP or PP tear. Patients with a normal PP had a mean protrusion length of 4.11 ± 1.35 mm on radiographs and 2.61 ± 1.31 mm on MR images, whereas those with a PP tear had a mean protrusion length of 4.75 ± 1.53 and 3.05 ± 1.34 mm, respectively. ROC curve analysis showed that protrusion length cutoff values of 5.47 mm measured on radiographs and 3.17 mm on MR images were correlated with MTP PP tear. We identified a linear correlation between second metatarsal protrusion measured on MRI and that measured on radiography, with values about 35% higher for the latter. Our study showed an association between length of protrusion of the second metatarsal and PP rupture and identified a cutoff value for the second meta-tarsal overlength that is associated with these tears.
本研究旨在确定第二跖骨在 MRI 和负重足部 X 线摄影上的相对突出长度是否可以预测第二跖趾（MTP）关节跖板（PP）撕裂的 MRI 诊断。我们回顾性评估了 166 例连续患者（211 只脚）。患者接受了负重足部 X 线摄影和前足 MRI 检查。使用 Coughlin 方法，两名独立观察者在 X 线和 MRI 上测量第二跖骨突出长度。MRI 结果分为正常 PP、完全 PP 撕裂、退行性或部分 PP 撕裂。患者的平均年龄为 47 ± 14.6（SD）岁，131 例（78.9%）为女性。MRI 测量与 X 线测量高度相关（ = 0.882；95%CI，0.866-0.898； < 0.001）。突出长度与被归类为正常 PP 或 PP 撕裂的病例之间存在显著相关性。正常 PP 的患者在 X 线片上的平均突出长度为 4.11 ± 1.35mm，在 MRI 图像上为 2.61 ± 1.31mm，而 PP 撕裂的患者分别为 4.75 ± 1.53mm 和 3.05 ± 1.34mm。ROC 曲线分析显示，X 线片上测量的突出长度截断值为 5.47mm，MRI 上为 3.17mm，与 MTP PP 撕裂相关。我们发现 MRI 上测量的第二跖骨突出长度与 X 线片上测量的突出长度之间存在线性相关性，后者的值比前者高约 35%。本研究表明，第二跖骨突出长度与 PP 破裂之间存在关联，并确定了与这些撕裂相关的第二跖骨过长的截断值。
