Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlægevej 16, 1870 Frederiksberg, Denmark.
Birkerød Dyreklinik, Hovedgaden 25, 3460 Birkerød, Denmark.
Res Vet Sci. 2021 Mar;135:127-133. doi: 10.1016/j.rvsc.2021.01.005. Epub 2021 Jan 6.
Centre of rotation of angulation (CORA)-based levelling osteotomy (CBLO) is a recent addition to surgical procedures for stabilization of the cranial cruciate ligament-deficient canine stifle joint. Careful identification of the CORA location preoperatively and use of this location intraoperatively are required to ensure accurate correction of the tibial plateau angle. Limited data are available regarding the magnitude and source of potential errors during planning and execution of CBLO. A geometric model enabling isolation of various error sources is described. Landmarks were derived from tibial radiographs (n = 50) by 5 observers and used to define proximal and distal anatomical axes for simulation of CBLO. Observer-specific CORA locations with mean landmark data were used to assess planning errors, and simulated malpositioning of the CORA at 10 mm from the ideal location was used to assess surgical errors. Planning errors result mainly from tibial plateau misidentification, with CORA locations dispersed up to ±10 mm proximodistally from ideal (95% confidence). Malpositioning of the CORA during surgery causes equal and opposite changes in tibial plateau angle (TPA) and anatomical-mechanical axis angles, and varying degrees of translation and limb length changes. The magnitude of these changes is dependent on initial TPA and limb length, with smaller dogs and steeper tibial plateaus resulting in larger errors. Optimal planning and execution are required to achieve the planned outcome of CBLO. The main source of error in our simulation is identification of the tibial plateau. While both pre- and intraoperative errors influenced TPA, based on our geometric model the effect in larger dogs may not be clinically significant. If distalisation of the CORA is required during surgery, compensation of the CORA angle to maintain the target TPA is possible.
基于旋转中心定位的角度校正截骨术（CORA-based leveling osteotomy，CBLO）是一种用于稳定十字韧带断裂犬膝关节的新型手术方法。为确保准确矫正胫骨平台角度，术前需仔细确定 CORA 位置，并在术中使用该位置。目前关于 CBLO 规划和执行过程中潜在误差的大小和来源的相关数据有限。本研究介绍了一种可隔离各种误差源的几何模型。通过 5 名观察者从胫骨 X 线片中提取标志点，并用于模拟 CBLO 以定义近侧和远侧解剖轴。使用具有平均标志点数据的特定观察者 CORA 位置来评估规划误差，并模拟 CORA 在距理想位置 10mm 处的错位以评估手术误差。规划误差主要源于胫骨平台的误识别，CORA 位置在近-远侧方向上与理想位置相差 10mm 以内（95%置信区间）。手术中 CORA 的错位会导致胫骨平台角度（TPA）和解剖力学轴角度的相等且相反的变化，并伴有不同程度的平移和肢体长度变化。这些变化的幅度取决于初始 TPA 和肢体长度，小型犬和更陡的胫骨平台会导致更大的误差。需要进行最优的规划和执行，以实现 CBLO 的预期结果。在我们的模拟中，主要的误差源是胫骨平台的识别。尽管术前和术中误差都影响 TPA，但根据我们的几何模型，在较大的犬中，这种影响可能不具有临床意义。如果在手术中需要 CORA 的远移，可以通过补偿 CORA 角度来维持目标 TPA。
