Hirschmann Michael T, Khan Zainab Aqeel, Sava Manuel P, von Eisenhart-Rothe Rüdiger, Graichen Heiko, Vendittoli Pascal-André, Riviere Charles, Chen Antonia F, Leclercq Vincent, Amsler Felix, Lustig Sebastien, Bonnin Michel
Department of Orthopedic Surgery and Traumatology, Kantonsspital Baselland, Bruderholz, Switzerland.
Department of Clinical Research, Research Group Michael T. Hirschmann, Regenerative Medicine & Biomechanics, University of Basel, Basel, Switzerland.
Knee Surg Sports Traumatol Arthrosc. 2024 Feb;32(2):473-489. doi: 10.1002/ksa.12066. Epub 2024 Jan 31.
One of the most pertinent questions in total knee arthroplasty (TKA) is: what could be considered normal coronal alignment? This study aims to define normal, neutral, deviant and aberrant coronal alignment using large data from a computed tomography (CT)-scan database and previously published phenotypes.
Coronal alignment parameters from 11,191 knee osteoarthritis (OA) patients were measured based on three dimensional reconstructed CT data using a validated planning software. Based on these measurements, patients' coronal alignment was phenotyped according to the functional knee phenotype concept. These phenotypes represent an alignment variation of the overall hip knee ankle angle (HKA), femoral mechanical angle (FMA) and tibial mechanical angle (TMA). Each phenotype is defined by a specific mean and covers a range of ±1.5° from this mean. Coronal alignment is classified as normal, neutral, deviant and aberrant based on distribution frequency. Mean values and distribution among the phenotypes are presented and compared between two populations (OA patients in this study and non-OA patients from a previously published study).
The arithmetic HKA (aHKA), combined normalised data of FMA and TMA, showed that 36.0% of knees were neutral within ±1 SD from the mean in both angles, 44.3% had either a TMA or a FMA within ±1-2 SD (normally aligned), 15.3% of the patients were deviant within ±2-3 SD and only 4.4% of them had an aberrant alignment (±3-4 SD in 3.4% and >4 SD in 1.0% of the patients respectively). However, combining the normalised data of HKA, FMA and TMA, 15.4% of patients were neutral in all three angles, 39.7% were at least normal, 27.7% had at least one deviant angle and 17.2% had at least one aberrant angle. For HKA, the males exhibited 1° varus and females were neutral. For FMA, the females exhibited 0.7° more valgus in mean than males and grew 1.8° per category (males grew 2.1° per category). For TMA, the males exhibited 1.3° more varus than females and both grew 2.3° and 2.4° (females) per category. Normal coronal alignment was 179.2° ± 2.8-5.6° (males) and 180.5 > ± 2.8-5.6° (females) for HKA, 93.1 > ± 2.1-4.2° (males) and 93.8 > ± 1.8-3.6° (females) for FMA and 86.7 > ± 2.3-4.6° (males) and 88 > ± 2.4-4.8° (females) for TMA. This means HKA 6.4 varus or 4.8° valgus (males) or 5.1° varus to 6.1° valgus was considered normal. For FMA HKA 1.1 varus or 7.3° valgus (males) or 0.2° valgus to 7.4° valgus was considered normal. For TMA HKA 7.9 varus or 1.3° valgus (males) or 6.8° varus to 2.8° valgus was considered normal. Aberrant coronal alignment started from 179.2° ± 8.4° (males) and 180.5 > ± 8.4° (females) for HKA, 93.1 > ± 6.3° (males) 93.8 > ± 5.4° (females) for FMA and 86.7 > ± 6.9° (males) and 88 > ± 7.2° (females) for TMA. This means HKA > 9.2° varus or 7.6° valgus (males) or 7.9° varus to 8.9° valgus was considered aberrant.
Definitions of neutrality, normality, deviance as well as aberrance for coronal alignment in TKA were proposed in this study according to their distribution frequencies. This can be seen as an important first step towards a safe transition from the conventional one-size-fits-all to a more personalised coronal alignment target. There should be further definitions combining bony alignment, joint surfaces' morphology, soft tissue laxities and joint kinematics.
III.
全膝关节置换术（TKA）中最相关的问题之一是：什么可被视为正常的冠状位对线？本研究旨在利用来自计算机断层扫描（CT）数据库的大数据和先前发表的表型来定义正常、中立、偏差和异常的冠状位对线。
使用经过验证的规划软件，基于三维重建的CT数据测量11191例膝骨关节炎（OA）患者的冠状位对线参数。基于这些测量结果，根据功能性膝关节表型概念对患者的冠状位对线进行表型分析。这些表型代表了整体髋膝踝角（HKA）、股骨机械角（FMA）和胫骨机械角（TMA）的对线变化。每个表型由一个特定的平均值定义，并涵盖该平均值±1.5°的范围。根据分布频率将冠状位对线分为正常、中立、偏差和异常。呈现了各表型之间的平均值和分布情况，并在两个人群（本研究中的OA患者和先前发表研究中的非OA患者）之间进行了比较。
算术HKA（aHKA），即FMA和TMA的综合标准化数据显示，36.0%的膝关节在两个角度的平均值±1标准差范围内为中立，44.3%的膝关节在±1 - 2标准差范围内（正常对线）有TMA或FMA，15.3%的患者在±2 - 3标准差范围内偏差，只有4.4%的患者有异常对线（分别有3.4%的患者在±3 - 4标准差范围内，1.0%的患者>4标准差）。然而，将HKA、FMA和TMA的标准化数据相结合，15.4%的患者在所有三个角度均为中立，39.7%至少为正常，27.7%至少有一个偏差角度，17.2%至少有一个异常角度。对于HKA，男性表现为1°内翻，女性为中立。对于FMA，女性平均外翻比男性多0.7°，每类别增长1.8°（男性每类别增长2.1°）。对于TMA，男性内翻比女性多1.3°，两者每类别均增长2.3°和2.4°（女性）。HKA的正常冠状位对线为179.2°±2.8 - 5.6°（男性）和180.5°±2.8 - 5.6°（女性），FMA为93.1°±2.1 - 4.2°（男性）和93.8°±1.8 - 3.6°（女性），TMA为86.7°±2.3 - 4.6°（男性）和88°±2.4 - 4.8°（女性）。这意味着HKA 6.4°内翻或4.8°外翻（男性）或5.1°内翻至6.1°外翻被视为正常。对于FMA，HKA 1.1°内翻或7.3°外翻（男性）或0.2°外翻至7.4°外翻被视为正常。对于TMA，HKA 7.9°内翻或1.3°外翻（男性）或6.8°内翻至2.8°外翻被视为正常。异常冠状位对线从HKA的179.2°±8.4°（男性）和180.5°±8.4°（女性）开始，FMA为93.1°±6.3°（男性）93.8°±5.4°（女性），TMA为86.7°±6.9°（男性）和88°±7.2°（女性）。这意味着HKA>9.2°内翻或7.6°外翻（男性）或7.9°内翻至8.9°外翻被视为异常。
本研究根据冠状位对线的分布频率提出了TKA中中立、正常、偏差以及异常的定义。这可被视为从传统的一刀切向更个性化的冠状位对线目标安全过渡的重要第一步。还应结合骨对线、关节面形态学、软组织松弛度和关节运动学进行进一步定义。
III级。
