Foot and Ankle Surgery Department, Honghui Hospital of Xi'an Jiaotong University, Xi'an, China.
BMC Musculoskelet Disord. 2023 Aug 29;24(1):683. doi: 10.1186/s12891-023-06824-w.
Alignment is indispensable for the foot and ankle function, especially in the hindfoot alignment. In the preoperative planning of patients with varus or valgus deformity, the precise measurement of the hindfoot alignment is important. A new method of photographing and measuring hindfoot alignment based on X-ray was proposed in this study, and it was applied in the assessment of flatfoot.
This study included 28 patients (40 feet) with flatfeet and 20 volunteers (40 feet) from January to December 2018. The hindfoot alignment shooting stand independently designed by our department was used to take hindfoot alignment X-rays at 10 degree, 15 degree, 20 degree, 25 degree, and 30 degree. We measured the modified tibio-hindfoot angle (THA) at the standard hindfoot aligment position (shooting at 20 degree) and evaluated consistency with the van Dijk method and the modified van Dijk method. In addition, we observed the visibility of the tibiotalar joint space from all imaging data at five projection angles and evaluated the consistency of the modified THA method at different projection angles. The angle of hindfoot valgus of flatfoot patients was measured using the modified THA method.
The mean THA in the standard hindfoot aligment view in normal people was significantly different among the three evaluation methods (P < .001). The results from the modified THA method were significantly larger than those from the Van Dijk method (P < .001) and modified Van Dijk method (P < .001). There was no significant difference between the results of the modified THA method and the weightbearing CT (P = .605), and the intra- and intergroup consistency were the highest in the modified THA group. The tibiotalar space in the normal group was visible in all cases at 10 degree, 15 degree, and 20 degree; visible in some cases at 25 degree; and not visible in all cases at 30 degree. In the flatfoot group, the tibiotalar space was visible in all cases at 10 degree, visible in some cases at 15 degree and 20 degree, and not visible in all cases at 25 degree and 30 degree. In the normal group, the modified THA was 4.84 ± 1.81 degree at 10 degree, 4.96 ± 1.77 degree at 15 degree, and 4.94 ± 2.04 degree at 20 degree. No significant differences were found among the three groups (P = .616). In the flatfoot group, the modified THA of 18 feet, which was visible at 10 degree, 15 degree and 20 degree, was 13.58 ± 3.57 degree at 10 degree, 13.62 ± 3.83 degree at 15 degree and 13.38 ± 4.06 degree at 20 degree. There were no significant differences among the three groups (P = .425).
The modified THA evaluation method is simple to use and has high inter- and intragroup consistency. It can be used to evaluate hindfoot alignment. For patients with flatfeet, the 10 degree position view and modified THA measurement can be used to evaluate hindfoot valgus.
足部和踝关节的功能离不开对线，尤其是在后足对线中。在足内翻或外翻畸形患者的术前规划中，精确测量后足对线非常重要。本研究提出了一种基于 X 线的新的后足对线拍摄和测量方法，并将其应用于扁平足的评估中。
本研究纳入了 2018 年 1 月至 12 月的 28 例（40 足）扁平足患者和 20 名志愿者（40 足）。使用我们科室自主设计的后足对线拍摄支架，分别在 10°、15°、20°、25°和 30°拍摄后足对线 X 线片。在标准后足对线位置（20°拍摄）测量改良胫距后足角（THA），并与 van Dijk 法和改良 van Dijk 法进行一致性评估。此外，我们观察了五个投照角度下所有影像学数据中距跟关节间隙的可见性，并评估了改良 THA 方法在不同投照角度下的一致性。使用改良 THA 方法测量扁平足患者的后足外翻角度。
正常人标准后足对线视图中，三种评估方法的平均 THA 差异均有统计学意义（P<0.001）。改良 THA 方法的结果明显大于 van Dijk 法（P<0.001）和改良 van Dijk 法（P<0.001）。改良 THA 方法的结果与负重 CT 无显著差异（P=0.605），改良 THA 组的组内和组间一致性最高。正常组在 10°、15°和 20°时所有病例距跟关节间隙均可见；25°时部分病例可见；30°时所有病例均不可见。扁平足组在 10°时所有病例均可见，15°和 20°时部分病例可见，25°和 30°时所有病例均不可见。正常组在 10°时改良 THA 为 4.84±1.81°，15°时为 4.96±1.77°，20°时为 4.94±2.04°。三组间差异无统计学意义（P=0.616）。扁平足组 18 足在 10°、15°和 20°时可见，改良 THA 分别为 10°时 13.58±3.57°，15°时 13.62±3.83°，20°时 13.38±4.06°。三组间差异无统计学意义（P=0.425）。
改良 THA 评估方法简单易用，组内和组间一致性高。可用于评估后足对线。对于扁平足患者，10°位视图和改良 THA 测量可用于评估后足外翻。
