Objective

To quantify the surface area of the talus accessible with a uniplanar and a biplanar medial malleolus osteotomy. Our secondary purpose study is to quantify the amount of weightbearing area that each osteotomy effects on the tibial articular surface.

Patients and methods

Eight ankle joint specimens were dissected for this study. The uniplanar osteotomy was performed first. A K-wire marked the limits of access at two different angles: 90° and 30°. The boundaries were marked with a skin marker. Wedges were then created on the tibia plafond, and the osteotomy was converted into a biplanar one. Measurements were repeated again for this osteotomy. The talus, the tibial plafond, and the medial malleolus were then excised. Images were taken and then electronically calibrated for two-dimensional digital measurement of accessible areas. Areas of perpendicular and 30-degree access were recorded for both osteotomies. The articular surface of the tibia was also measured, and an area analysis was performed to calculate the amount of weightbearing cartilage removed by each osteotomy.

Results

Almost the entire sagittal plane was accessible with both osteotomies. At a 30° angle, bone purchase was achieved for 67.7 % of the talar articular surface with the uniplanar osteotomy and for 74.8 % with the biplanar osteotomy. At a 90° angle, uniplanar osteotomy provided access to 32.7 % of the talar articular area, whereas the biplanar osteotomy achieved an average coverage of 52.8 %. The difference was statistically significant. On average, 25.3 % of the weightbearing area of the tibial plafond is affected when a biplanar osteotomy is performed.

Conclusion

Medial malleolar osteotomy provides varying degrees of access to the talar dome depending on how it is performed. A wedge-shaped biplanar osteotomy provides greater access and is therefore more suitable for defects located deeper on the talar dome. Despite providing wider access, it results in greater disruption of the weightbearing cartilage of the tibial plafond.

Level of evidence

Level V.

中文翻译：

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楔入或不楔入；两种内踝截骨方式的尸体比较研究

客观的

量化单平面和双平面内踝截骨术可及的距骨表面积。我们的第二个目的研究是量化每次截骨术对胫骨关节面的负重面积。

患者和方法

本研究解剖了八个踝关节标本。首先进行单平面截骨术。克氏针以两个不同的角度标记了进入限制：90° 和 30°。边界用皮肤标记标记。然后在胫骨平台上创建楔形，并将截骨术转换为双平面截骨术。再次对该截骨术进行测量。然后切除距骨、胫骨平台和内踝。拍摄图像，然后对可访问区域的二维数字测量进行电子校准。记录了两种截骨术的垂直和 30 度进入区域。还测量了胫骨的关节面，并进行面积分析以计算每次截骨术去除的承重软骨量。

结果

两种截骨术几乎都可以接触到整个矢状面。在 30° 角，单平面截骨术和双平面截骨术分别为 67.7% 和 74.8% 的距骨关节面实现了骨购买。在 90° 角，单平面截骨术提供了 32.7% 的距骨关节区，而双平面截骨术的平均覆盖率为 52.8%。差异具有统计学意义。平均而言，进行双平面截骨术时，胫骨平台 25.3% 的承重区域会受到影响。

结论

内踝截骨术提供不同程度的接近距骨圆顶的通路，具体取决于它的执行方式。楔形双平面截骨术提供了更大的通路，因此更适合位于距骨圆顶较深的缺损。尽管提供了更广泛的通路，但它会导致胫骨平台的承重软骨受到更大的破坏。

证据等级

第五级。