Department of Orthopaedic Surgery and Traumatology, Kantonsspital Baselland (Bruderholz, Liestal, Laufen), 4101, Bruderholz, Switzerland.
University of Basel, Basel, Switzerland.
Knee Surg Sports Traumatol Arthrosc. 2019 May;27(5):1385-1393. doi: 10.1007/s00167-019-05508-0. Epub 2019 Apr 12.
There is a lack of knowledge about the joint line orientation of the femur and tibia in non-osteoarthritic knees. The primary purpose of the present study was to evaluate the orientation of the joint lines in native non-osteoarthritic knees using 3D-reconstructed CT scans. The secondary purpose was to identify knee phenotypes to combine the information of the femoral and tibial alignment.
A total of 308 non-osteoarthritic knees of 160 patients (male to female ratio = 102:58, mean age ± standard deviation 30 ± 7 years (16-44 years) were retrospectively included from our registry. All patients received CT of the knee according to the Imperial Knee Protocol. The orientation of the femoral and tibial joint line was measured in relation to their mechanical axis (femoral mechanical angle, FMA, and tibial mechanical angle, TMA) using a commercially planning software (KneePLAN 3D, Symbios, Yverdon les Bains, Switzerland). The values of FMA and TMA were compared between males and females. Descriptive statistics, such as means, ranges, and measures of variance (e.g. standard deviations), were presented. Based on these results, phenotypes were introduced for the femur and tibia. These phenotypes, based on FMA and TMA values, consist of a mean value and cover a range of ± 1.5° from this mean (3° increments). The distribution of femoral and tibial phenotypes, and their combinations (knee phenotypes) were calculated for the total group and for both genders.
The overall mean FMA ± standard deviation (SD) was 93.4° ± 2.0° and values ranged from 87.9° varus to 100° valgus. The overall mean TMA ± SD was 87.2° ± 2.4° with a range of 81.3° varus to 94.6° valgus. FMA and TMA showed significant gender differences (p < 0.01). Females showed more valgus alignment than males. The most common femoral phenotype was neutral in both genders. The most common tibial phenotype was neutral in the male knees (62.8%) and valgus (41.6%) in the female knees. In males, the most frequent combination (knee phenotype) was a neutral phenotype in the femur and a neutral phenotype in the tibia (25.6%). In females, it was a neutral femoral phenotype and a valgus tibial phenotype (28.3%).
3D-reconstructed CT scans confirmed the great variability of the joint line orientation in non-osteoarthritic knees. The introduced femoral and tibial phenotypes enable the evaluation of the femoral and tibial alignment together (knee phenotypes). The variability of knee phenotypes found in this young non-osteoarthritic population clearly shows the need for a more individualized approach in TKA.
III.
在非骨关节炎膝关节中，人们对股骨和胫骨的关节线方向缺乏了解。本研究的主要目的是使用三维重建 CT 扫描评估正常非骨关节炎膝关节的关节线方向。次要目的是确定膝关节表型，以结合股骨和胫骨对线的信息。
从我们的注册处回顾性纳入了 308 例非骨关节炎膝关节（160 例患者，男女比为 102:58，平均年龄 ± 标准差 30 ± 7 岁[16-44 岁]）。所有患者均根据帝国膝关节方案接受了膝关节 CT 检查。使用商业规划软件（KneePLAN 3D，Symbios，Yverdon les Bains，瑞士）测量股骨和胫骨关节线相对于其机械轴（股骨机械角 FMA 和胫骨机械角 TMA）的方向。比较了男性和女性之间的 FMA 和 TMA 值。给出了描述性统计，如平均值、范围和方差度量（例如标准差）。基于这些结果，引入了股骨和胫骨的表型。这些表型基于 FMA 和 TMA 值，由平均值和覆盖平均值 ± 1.5°的范围组成（3°增量）。计算了总组和两性的股骨和胫骨表型及其组合（膝关节表型）的分布。
总体平均 FMA ± 标准差（SD）为 93.4° ± 2.0°，范围从 87.9° 内翻到 100° 外翻。总体平均 TMA ± SD 为 87.2° ± 2.4°，范围从 81.3° 内翻到 94.6° 外翻。FMA 和 TMA 存在显著的性别差异（p<0.01）。女性的外翻角度大于男性。在两性中，最常见的股骨表型均为中立。在男性膝关节中，最常见的胫骨表型为中立（62.8%），在女性膝关节中为中立（41.6%）和外翻（41.6%）。在男性中，最常见的组合（膝关节表型）是股骨中立表型和胫骨中立表型（25.6%）。在女性中，它是股骨中立表型和胫骨外翻表型（28.3%）。
三维重建 CT 扫描证实了非骨关节炎膝关节关节线方向的极大变异性。引入的股骨和胫骨表型能够一起评估股骨和胫骨的对线（膝关节表型）。在这个年轻的非骨关节炎人群中发现的膝关节表型的变异性清楚地表明，在 TKA 中需要更个体化的方法。
III 级。
