膝关节周围截骨术，怎么测量才准确?一项来自德国的研究

Mechanical alignment correction through osteotomy is an effective joint-preserving treatment for unicompartmental knee joint degeneration relieving pressure off the affected compartment [3-5, 10, 28, 30, 34, 36, 38, 43]. Evidence-based indications include meniscus replacement [20, 21], cartilage regenerative surgery [2, 7] or anterior cruciate ligament deficiency [13], where osteotomy improves biomechanical load distribution. Successful osteotomy requires precise preoperative planning.

通过截骨术进行机械力线矫正是一种有效的关节保留治疗方法，用于单间室膝关节退变，减轻受影响间室的压力[3-5, 10, 28, 30, 34, 36, 38, 43]。基于证据的适应症包括半月板置换[20, 21]、软骨再生手术[2, 7]或前交叉韧带缺损[13]，在这些情况下，截骨术可以改善生物力学负荷分布。成功的截骨术需要精确的术前规划。

Currently, preoperative planning is mainly performed on two-dimensional weight-bearing lower limb radiographs [24, 32, 37], with methods based on Paley's principle and frameworks by Miniaci, Jakob, and Strecker [24, 32, 37]. These methods have evolved from printed 2D radiographs to advanced digital techniques [11], with ongoing efforts to incorporate artificial intelligence [25, 41].

目前，术前规划主要在二维负重下肢 X 光片上进行[24, 32, 37]，采用基于 Paley 原理以及 Miniaci、Jakob 和 Strecker 框架的方法[24, 32, 37]。这些方法已从打印的二维 X 光片发展到先进的数字技术[11]，并持续努力将人工智能纳入其中[25, 41]。

Despite advancements, postoperative limb alignment often deviates from preoperative plans, with a reported accuracy of 1.5° (0.5–2.4°) for the mechanical femorotibial angle (mFA-mTA) [1]. This inaccuracy may be based result from reliance on wedge height measurements, which, while feasible intraoperatively, may be influenced by entry and hinge points [6, 35, 41].

尽管取得了进展，术后肢体对线常常偏离术前计划，据报道机械股胫角（mFA-mTA）的准确性为 1.5°（0.5–2.4°）[1]。这种不准确性可能源于对楔形高度测量的依赖，虽然术中可行，但可能受到入口和铰链点的影响[6, 35, 41]。

Measuring wedge height is straightforward intraoperatively, but its sensitivity to the osteotomy entry point and hinge location remains debated [15, 22, 23, 26, 27, 40, 42]. Variations in these points compared to preoperative plans might explain inaccuracies in postoperative alignment correction. The purpose of this simulation study was to investigate the impact of the selection of osteotomy entry and hinge point on typical preoperative planning parameters, such as wedge height, wedge angle and osteotomy depth in medial open wedge high tibial osteotomy (HTO) and lateral open wedge distal femur osteotomy (DFO). Additionally, the study aimed to determine whether the wedge angle provides superior reliability in preoperative limb alignment correction compared to wedge height. The hypothesis proposed that while the wedge angle remains a fixed parameter during preoperative planning, the wedge height can vary significantly based on the position of the hinge or entry point.

术中测量楔形高度是直接的，但其对截骨入口点和铰链位置的敏感性仍存在争议[15, 22, 23, 26, 27, 40, 42]。与术前计划相比，这些点的变化可能解释了术后矫正对齐的不准确性。 本模拟研究的目的是探讨在胫骨高位截骨术（HTO）和股骨远端截骨术（DFO）中，选择截骨入口和铰链点对典型术前规划参数（如楔形高度、楔形角度和截骨深度）的影响。此外，研究还旨在确定楔形角度在术前肢体对线矫正中是否比楔形高度提供更高的可靠性。 假设提出，在术前规划中，楔形角是一个固定参数，而楔形高度则会根据铰链或入口点的位置显著变化。

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看图片

相关解读为AI生成

Fig. 1: Preoperative Whole Leg Radiographs

• 内容:
  显示了膝关节内翻（genu varum，a图）和膝关节外翻（genu valgum，b图）的术前全腿负重位X线片。这些是标准的膝关节前位（knee forward position）X线片。
• 目的:
  展示用于研究的两种典型病例（内翻和外翻畸形），作为后续手术计划的基础。

• Fig. 2: Medial Open Wedge Proximal Tibial Osteotomy (HTO)     Planning
• 内容:
  展示了使用mediCAD®软件进行的胫骨近端内侧开放楔形截骨术（HTO）的规划过程。
• 关键点:
• 展示了如何通过改变截骨的起始点（entry point，A-C）和铰链点（hinge point，1-9）来创建多种截骨变体（每例27种）。
• 使用基于解剖标志的坐标系（coordinate system）以标准化的方式确定这些点，确保不同患者之间的可比性（如a图所示）。
• 所有变体的目标是将术后负重线（WBL）调整到胫骨平台内侧边缘起55.0%的位置。
• B6
  被认为是最佳铰链位置。
• **
  目的：**HTO变体创建过程的可视化表示。

• Fig. 3: Lateral Open Wedge Distal Femur Osteotomy (DFO)     Planning
• 内容:
  展示了使用mediCAD®软件进行的股骨远端外侧开放楔形截骨术（DFO）的规划过程。
• 关键点:
• 类似于HTO，通过改变起始点（A-C）和铰链点（1-7）创建了21种DFO变体。
• 使用标准化坐标系确定铰链和起始点（如a图所示）。
• 规划的目标是将WBL调整到胫骨平台内侧边缘起50.0%的位置。
• B7
  被认为是最佳铰链位置。
• **
  目的：**DFO变体创建过程的可视化表示。

• Fig. 4: Mathematical Prediction of Wedge Height
• 内容:
  展示了用于计算楔形高度的数学公式和几何原理。
• 关键点:
• 截骨楔形被视为一个等腰三角形，由两个全等的直角三角形组成。
• 使用正弦函数（sine function），根据截骨深度（osteotomy depth）和矫正角（α，开放角的一半）计算楔形高度。
• 公式：楔形高度 = 2 * (sin(0.5 * α) * 截骨深度)。
• **
  目的：**解释楔形高度和如何计算它。
• Fig. 5: Correlation Between Osteotomy Depth, Wedge Angle, and     Wedge Height
• 内容:
  展示了截骨深度、楔形角和楔形高度之间的相关性。
• 关键点:
• 每个数据点代表一个截骨变体，根据其截骨深度和楔形角的值进行定位。
• 点的颜色根据楔形高度的值从蓝色（低）到白色到红色（高）渐变。
• 图形直观地显示了这三个变量之间的正相关关系（图中未显示相关系数，但在结果部分有提及）。
• **
  目的：**说明骨切割深度和角度都会影响插入楔块的高度。

总而言之，这些图共同说明了研究的设计（通过改变截骨参数创建多个变体）、规划过程、以及用于计算和关联关键变量（楔形高度、楔形角、截骨深度）的数学原理。

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论文要点

英文为准，中文仅供参考

Key Points:关键点：

· Background: This study examines the reliability of measurement parameters in open wedge osteotomies around the knee, specifically comparing wedge angle to wedge height.
背景：本研究探讨了膝关节周围开放楔形截骨术中测量参数的可靠性，特别是比较楔形角度与楔形高度。

· Purpose: To determine whether wedge angle provides superior reliability compared to wedge height when planning medial open wedge high tibial osteotomies (HTOs) and lateral open wedge distal femur osteotomies (DFOs).
目的：确定在规划内侧开放楔形高位胫骨截骨术（HTOs）和外侧开放楔形远端股骨截骨术（DFOs）时，楔形角度是否比楔形高度提供更高的可靠性。

· Methods: 40 patients' radiographs (20 HTO, 20 DFO) were analyzed with 960 total osteotomy simulations by altering entry and hinge points.
方法：分析了 40 名患者的 X 光片（20 例 HTO，20 例 DFO），通过改变进入点和铰链点进行了 960 次截骨模拟。

· Key Finding: Wedge angle remained consistent (mean deviation: 0.1 ± 0.1°) while wedge height showed variability (mean deviation: 0.7 ± 0.5 mm).
关键发现：楔形角保持一致（平均偏差：0.1 ± 0.1°），而楔形高度显示出变异性（平均偏差：0.7 ± 0.5 毫米）。

· Mathematical Model: A formula was developed to predict wedge height from wedge angle and osteotomy depth with high accuracy (R = 0.998).
数学模型：开发了一个公式，可以从楔形角和截骨深度高精度预测楔形高度（R = 0.998）。

· Clinical Implication: Surgeons should prioritize wedge angle over wedge height in planning and consider intraoperative osteotomy depth measurements to achieve precise corrections.
临床意义：外科医生在规划时应优先考虑楔形角度而非楔形高度，并考虑术中截骨深度测量以实现精确矫正。

· Study Level: Level V simulation study.
研究水平：第五级模拟研究。

Detailed Outline:详细大纲：

1. Introduction & Background
引言与背景 

o Open wedge osteotomies are effective joint-preserving treatments for unicompartmental knee degeneration
开放楔形截骨术是治疗单间室膝关节退化的有效关节保留方法

o Current planning methods rely on 2D weight-bearing radiographs
目前的规划方法依赖于二维负重 X 光片

o Postoperative alignment often deviates from preoperative plans
术后对齐往往与术前计划有所偏差

o Reliance on wedge height measurements may contribute to inaccuracies
依赖楔形高度测量可能导致不准确

2. Methodology  方法论

o Retrospective simulation study of 40 patients (20 HTO, 20 DFO)
对 40 名患者（20 名 HTO，20 名 DFO）进行的回顾性模拟研究

o Multiple osteotomy variants created per case (27 for HTO, 21 for DFO)
每个病例创建了多个截骨变体（HTO 27 个，DFO 21 个）

o Standardized coordinate systems defined entry and hinge points
定义了标准化的坐标系入口和铰链点

o 960 total simulations analyzed across all patients
分析了所有患者的 960 次模拟

o Mathematical formula developed to predict wedge height
开发了数学公式来预测楔形高度

3. Key Results  关键结果 

o Wedge angle remained constant across variants (0.1 ± 0.1° deviation)
楔形角在不同变体中保持恒定（偏差为 0.1 ± 0.1°）

o Wedge height showed variability (0.7 ± 0.5 mm deviation)
楔形高度显示出变异性（偏差为 0.7 ± 0.5 毫米）

o Strong correlation between wedge height and opening angle (R = 0.83)
楔形高度与开口角之间存在强相关性（R = 0.83）

o Moderate correlation between wedge height and osteotomy depth (R = 0.60)
楔形高度与截骨深度之间存在中等相关性（R = 0.60）

o Mathematical predictions closely matched actual wedge height values
数学预测与实际楔形高度值非常吻合

4. Clinical Implications  临床意义 

o Relying solely on wedge height is insufficient due to variations in entry/hinge points
仅依赖楔形高度是不够的，因为入口/铰链点的变化

o Wedge angle is a more reliable parameter for planning
楔形角度是更可靠的规划参数

o Surgeons should measure osteotomy depth intraoperatively to adjust wedge height
外科医生应在术中测量截骨深度以调整楔形高度

o Precise alignment of preoperative planning with intraoperative execution is critical
术前计划与术中执行的精确对齐至关重要

o Correction table can help surgeons recalculate wedge height if deviations occur
矫正表可以帮助外科医生在出现偏差时重新计算楔形高度

5. Study Limitations  研究局限性 

o Simulation-only design (no physical osteotomies performed)
仅模拟设计（未进行实际截骨）

o 2D analysis may not account for 3D effects
二维分析可能无法考虑三维效应

o Single rater at one center
单一评估者在一个中心

o Did not account for bony characteristics, soft tissue, or implant sizing
未考虑骨骼特征、软组织或植入物尺寸

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关键问题问答

可盖住右侧答案，尝试自我测试

Study Question  研究问题	Answer  回答
What was the primary hypothesis?   主要假设是什么？	Wedge angle remains fixed during  preoperative planning, while wedge height varies based on hinge or entry  point position.   在术前计划中，楔形角度保持不变，而楔形高度根据铰链或入口点的位置而变化。
How many osteotomy simulations were  performed?   进行了多少次截骨模拟？	960 simulations (27 variants per HTO case  and 21 variants per DFO case).   960 次模拟（每个 HTO 病例 27 个变体，每个 DFO 病例 21 个变体）。
What was the mean deviation in wedge  angle across variants?   各变体之间的楔形角平均偏差是多少？	0.1 ± 0.1° (range 0.0-0.4°)   0.1 ± 0.1°（范围 0.0-0.4°）
What was the mean deviation in wedge  height across variants?   各变体间楔形高度的平均偏差是多少？	0.7 ± 0.5 mm (range 0.0-2.6 mm)   0.7 ± 0.5 毫米（范围 0.0-2.6 毫米）
What correlation was found between wedge  height and opening angle?   楔形高度与开口角度之间发现了什么相关性？	Strong positive correlation (R = 0.83, p  < 0.001)   强正相关（R = 0.83，p < 0.001）
What correlation was found between wedge  height and osteotomy depth?   楔形高度与截骨深度之间发现了什么相关性？	Moderate positive correlation (R = 0.60,  p < 0.001)   中等正相关（R = 0.60，p < 0.001）
How accurate was the mathematical  prediction of wedge height?   数学预测的楔形高度有多准确？	Highly accurate with R = 0.998, p <  0.001, mean difference of -0.01 ± 0.1 mm   高度准确，R = 0.998，p < 0.001，平均差异为-0.01 ± 0.1 mm
What factors significantly influenced  wedge height in regression analysis?   回归分析中哪些因素显著影响了楔形高度？	Opening angle (estimate = 0.9, p <  0.001) and osteotomy depth (estimate = 0.1, p < 0.001)   开口角度（估计值 = 0.9，p < 0.001）和截骨深度（估计值 = 0.1，p < 0.001）
What is the main clinical recommendation  based on findings?   基于研究结果的主要临床建议是什么？	Prioritize wedge angle over wedge height  in planning, and measure osteotomy depth intraoperatively to adjust wedge  height when deviations occur.   在规划中优先考虑楔形角度而非楔形高度，并在术中测量截骨深度以在出现偏差时调整楔形高度。
What is the level of evidence for this  study?   这项研究的证据水平是什么？	Level V (simulation study)   第五级（模拟研究）

DISCUSSION讨论

This study identified the wedge angle as a more reliable parameter than wedge height in planning open wedge osteotomies for HTO and DFO. Relying solely on wedge height can be problematic, as variations in the planned osteotomy entry and hinge points may compromise the accuracy of postoperative correction. The observed positive correlation between wedge height, osteotomy angle and depth supports this finding, as the calculation of wedge height is fundamentally based on the ray theorem, which incorporates both osteotomy depth and wedge angle. These results have important clinical implications. Any deviation in entry or hinge points affects wedge height and osteotomy depth, emphasizing the need for precise adherence to preoperative planning. To minimize errors, surgeons are encouraged to use intraoperative fluoroscopy to verify hinge positioning and osteotomy depth. Importantly, the study found that the wedge angle remained consistent across cases where preoperative planning aimed for identical limb axis corrections. This consistency underscores the value of wedge angle measurement as a reliable intraoperative tool for verifying alignment. This study highlights the need to translate the two-dimensional wedge angle into a three-dimensional operative setting for open wedge osteotomies. This is typically achieved by converting the planned wedge angle into the corresponding wedge height required for the desired correction, a process first introduced by Hernigou's correction table [11]. Intraoperative alterations to the osteotomy entry point and hinge point can lead to unintended changes in the osteotomy depth and wedge height, resulting in undesired postoperative outcomes.
本研究发现，在规划 HTO 和 DFO 的开放楔形截骨术时，楔形角比楔形高度更为可靠。仅依赖楔形高度可能会出现问题，因为计划的截骨入口和铰链点的变化可能会影响术后矫正的准确性。 观察到的楔形高度、截骨角度和深度之间的正相关关系支持了这一发现，因为楔形高度的计算从根本上基于射线定理，该定理结合了截骨深度和楔形角度。这些结果具有重要的临床意义。任何进入点或铰链点的偏差都会影响楔形高度和截骨深度，强调了精确遵循术前计划的必要性。 为了减少误差，鼓励外科医生使用术中透视来验证铰链位置和截骨深度。重要的是，研究发现，在术前计划旨在实现相同肢体轴线矫正的病例中，楔形角保持一致。这种一致性强调了楔形角测量作为验证对线的可靠术中工具的价值。 本研究强调了在开放楔形截骨术中，将二维楔形角度转化为三维手术环境的重要性。这通常通过将计划的楔形角度转换为实现所需矫正所需的相应楔形高度来实现，这一过程最初由 Hernigou 的矫正表引入[11]。 术中改变截骨入口点和铰链点可能导致截骨深度和楔形高度的意外变化，从而产生不理想的术后结果。

A similar study found no significant changes in wedge height with varying osteotomy entry points [23]. This finding does not align with our results, as different starting points alter osteotomy depth and wedge height. Differences may be attributed to small sample sizes. Limited variability, or the comparisons of absolute values without considering the association between osteotomy depth and mediolateral diameter.
一项类似的研究发现，不同截骨入路点的楔形高度没有显著变化[23]。这一发现与我们的结果不一致，因为不同的起始点会改变截骨深度和楔形高度。差异可能归因于样本量小、变异性有限，或在比较绝对值时未考虑截骨深度与内外侧直径之间的关联。

Experimental findings in cadaveric specimens further support the dependency between hinge position and wedge height, showing that altering the hinge position while maintaining a constant wedge height significantly affects the MPTA in HTO [15].
尸体标本的实验结果进一步支持了铰链位置与楔形高度之间的依赖性，表明在保持楔形高度不变的情况下改变铰链位置会显著影响 HTO 中的 MPTA[15]。

Based on the study's results, surgeons must closely align preoperative planning with intraoperative execution. Accurate placement of the entry and hinge points during surgery is critical for achieving proper limb alignment. In cases of deviations, surgeons can rely on the correction table (Table1) and measure osteotomy depth and recalculate wedge height, maintaining the planned correction angle. This requires fluoroscopy-guided measurements orthogonal to the hinge axis, with the knee positioned in the anterior–posterior direction and aligned horizontally. Maintaining the hinge axis in the anteroposterior plane is essential to avoid unintended alterations in the sagittal plane, as hinge position significantly affects the posterior tibial slope in HTO [12, 14, 39]. Bone loss from the saw blade's thickness should also be accounted for to enhance accuracy. Minor deviations from preoperative plans can significantly impact limb alignment, knee functionality and arthrosis progression [8, 19].
根据研究结果，外科医生必须将术前计划与术中执行紧密对齐。手术期间准确放置入口点和铰链点对于实现正确的肢体对位至关重要。在出现偏差的情况下，外科医生可以依赖校正表（表 1），测量截骨深度并重新计算楔形高度，以保持计划的校正角度。 这需要在透视引导下进行与铰链轴正交的测量，膝关节应置于前后方向并水平对齐。保持铰链轴在前后平面内至关重要，以避免在矢状面上产生意外变化，因为铰链位置显著影响 HTO 中的胫骨后倾角[12, 14, 39]。还应考虑锯片厚度造成的骨量损失以提高准确性。 术前计划的微小偏差可能会显著影响肢体对齐、膝关节功能和关节炎的进展[8, 19]。

Techniques such as intraoperative measurement of wedge height using metal probes, calipers, or fluoroscopy, or assessing alignment through radiographs, alignment rods, calibrated grids or cable methods, can verify corrections effectively [17,33, 44]. Although navigated osteotomies have been introduced, they have not demonstrated superior accuracy over traditional methods [29].
术中通过金属探针、卡尺或透视测量楔形高度，或通过 X 光片、对准杆、校准网格或电缆方法评估对线，可以有效验证矫正效果[17, 33, 44]。尽管导航截骨技术已被引入，但其准确性并未显示出优于传统方法[29]。

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