Teng Yuanjun, Yu Jian, Zhang Kangrui, Da Lijun, Li Sixian, Zhou Jianming, Chen Wenming, Wang Xu, Ma Xin
Department of Orthopedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Department of Orthopedic Surgery, Huashan Hospital, Fudan University, Shanghai, China.
Orthop Surg. 2025 Sep;17(9):2680-2688. doi: 10.1111/os.70111. Epub 2025 Jul 24.
The posterior tibial slope (PTS) is essential in the assessment of ankle alignment. However, its standardized reference value has not been adequately investigated. This study aims to compare the PTS of the ankle joint on virtual radiographs and CT images and determine the effect of participants' demographic characteristics on the PTS.
A retrospective analysis was conducted in healthy populations who underwent CT scans of the ankle joint. A total of 106 participants (53 males and 53 females) were included in our study. The three-dimensional model of the ankle joint was reconstructed by CT images, and the standard coronal and sagittal planes were produced using the anatomical coordinate system. The PTS was measured on different CT sagittal planes and virtual radiographs. All measurements were performed using three reference axes, including the anterior cortex axis, the anatomical axis, and the posterior cortex axis of the tibial shaft. Subgroup and correlation analyses were performed to investigate the effect of participants' demographic characteristics (the age, height, gender, and BMI) on the PTS. Statistical comparisons between two groups were performed using independent t-tests, while variations across sagittal planes and reference axes were analyzed through one-way analysis of variance.
The mean values of PTS varied from 76.7° to 83.4° on different sagittal planes of CT images, and there was an increasing trend for PTS from the medial to lateral CT images. The mean values of PTS on the virtual radiograph were 81.6°, 82.3°, and 80.8° for the anterior cortex, anatomical, and posterior cortex axes, respectively. Significant differences in PTS measurements were found between CT images and virtual radiographs (p < 0.05). However, no differences were found while using different reference axes on PTS measurements (p < 0.05). Subgroup analysis showed females had a greater PTS than males, indicating a gender-based difference in the anatomy of the PTS.
The PTS varied on CT images and radiographs, and the anterior cortex, anatomical, and posterior cortex axes do not significantly influence the PTS measurements. The observed gender-based differences highlight the need for individualized surgical planning and the development of sex-specific implants.
胫后斜率（PTS）在踝关节对线评估中至关重要。然而，其标准化参考值尚未得到充分研究。本研究旨在比较踝关节在虚拟X线片和CT图像上的PTS，并确定参与者人口统计学特征对PTS的影响。
对接受踝关节CT扫描的健康人群进行回顾性分析。本研究共纳入106名参与者（53名男性和53名女性）。通过CT图像重建踝关节的三维模型，并使用解剖坐标系生成标准冠状面和矢状面。在不同的CT矢状面和虚拟X线片上测量PTS。所有测量均使用三个参考轴进行，包括胫骨干的前皮质轴、解剖轴和后皮质轴。进行亚组分析和相关性分析，以研究参与者人口统计学特征（年龄、身高、性别和BMI）对PTS的影响。两组之间的统计比较采用独立t检验，而矢状面和参考轴之间的差异通过单因素方差分析进行分析。
CT图像不同矢状面上PTS的平均值在76.7°至83.4°之间变化，并且从内侧到外侧的CT图像上PTS有增加趋势。虚拟X线片上前皮质轴、解剖轴和后皮质轴的PTS平均值分别为81.6°、82.3°和80.8°。CT图像和虚拟X线片在PTS测量上存在显著差异（p < 0.05）。然而，在PTS测量中使用不同参考轴时未发现差异（p < 0.05）。亚组分析显示女性的PTS大于男性，表明PTS的解剖结构存在基于性别的差异。
PTS在CT图像和X线片上有所不同，前皮质轴、解剖轴和后皮质轴对PTS测量没有显著影响。观察到的基于性别的差异凸显了个性化手术规划和开发针对性别的植入物的必要性。
