Spitzer Elad, Ruzbarsky Joseph J, Doyle John B, Yin Kaitlyn L, Marx Robert G
Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
HSS J. 2018 Oct;14(3):251-257. doi: 10.1007/s11420-017-9591-3. Epub 2017 Dec 26.
Medial opening-wedge high tibial osteotomy (HTO) is one of the most common and effective HTO techniques, in which the proximal tibia is cut medially, leaving an intact lateral hinge of bone that can be opened to a variable amount for the desired correction, but the technical complications of lateral cortex fracture and intra-articular fracture are well described. The lateral bone hinge for medial opening-wedge HTO is crucial. If the hinge is too small, the tibia can fracture and become unstable, requiring further fixation. If the hinge is too large, the osteotomy can propagate into the joint as an intra-articular fracture when opening the osteotomy.
We propose a new technique that utilizes digital preoperative templating to improve the accuracy of the cut. Preoperative digital templating may allow the surgeon to reproducibly obtain a lateral bone hinge of 10 mm, while also reducing radiation exposure relative to the traditional fluoroscopically assisted technique.
Ten cadaver extremities from five cadavers were matched into pairs and randomized into two groups: those with and without preoperative templating. The templating protocol measures the distance between two points on the medial and lateral cortices, and 20 mm is subtracted to determine the depth of the saw cut (10 mm for the hinge and another 10 mm because the proximal tibia is oval in shape). The control method was done by making the cut using fluoroscopy with tactile feedback. Postoperative computed tomography scans were obtained of all legs to measure the width of the lateral bone hinge. Intraoperative fluoroscopy used during both techniques and the numbers of fluoroscopy shots were recorded.
We found neither the treatment group with preoperative planning nor the control group with the conventional technique had bone hinge widths that were different from the ideal 10 mm. The average hinge widths for the treatment and control groups were 11.2 and 11.5 mm, respectively. However, the treatment group was exposed to significantly less intraoperative fluoroscopy during the osteotomy cut. The average total number of fluoroscopy shots was 2.2 in the treatment group versus 6.3 for the control group.
This new preoperative planning technique achieves similar accuracy of the lateral bone hinge when compared to current methods but exposes the patient, surgeon, and staff to significantly less intraoperative radiation.
内侧开放楔形高位胫骨截骨术（HTO）是最常见且有效的HTO技术之一，该技术是在内侧截断胫骨近端，保留完整的外侧骨铰链，可将其打开不同程度以实现所需的矫正，但外侧皮质骨折和关节内骨折等技术并发症已有详细描述。内侧开放楔形HTO的外侧骨铰链至关重要。如果铰链过小，胫骨可能骨折并变得不稳定，需要进一步固定。如果铰链过大，截骨术打开时截骨可能延伸至关节内成为关节内骨折。
我们提出一种利用术前数字模板来提高截骨准确性的新技术。术前数字模板可使外科医生可重复性地获得10毫米的外侧骨铰链，同时相对于传统的透视辅助技术还能减少辐射暴露。
从五具尸体上取下的十条下肢配对后随机分为两组：有术前模板组和无术前模板组。模板方案测量内侧和外侧皮质上两点之间的距离，减去20毫米以确定锯切深度（铰链为10毫米，另外10毫米是因为胫骨近端呈椭圆形）。对照方法是通过透视并结合触觉反馈进行截骨。对所有下肢进行术后计算机断层扫描以测量外侧骨铰链的宽度。记录两种技术术中使用的透视情况及透视次数。
我们发现术前规划的治疗组和传统技术的对照组的骨铰链宽度与理想的10毫米均无差异。治疗组和对照组的平均铰链宽度分别为11.2毫米和11.5毫米。然而，治疗组在截骨过程中术中透视暴露明显更少。治疗组透视总次数平均为2.2次，而对照组为6.3次。
与当前方法相比，这种新的术前规划技术在外侧骨铰链的准确性方面取得了相似的效果，但使患者、外科医生和工作人员术中接受的辐射显著减少。
