León-Muñoz Vicente J, Hurtado-Avilés José, Santonja-Medina Fernando, Lajara-Marco Francisco, López-López Mirian, Moya-Angeler Joaquín
Department of Orthopaedic Surgery and Traumatology, Hospital General Universitario Reina Sofía, Avda. Intendente Jorge Palacios, 1, 30003 Murcia, Spain.
Instituto de Cirugía Avanzada de la Rodilla (ICAR), C. Barítono Marcos Redondo 1, 30005 Murcia, Spain.
J Clin Med. 2025 Mar 1;14(5):1679. doi: 10.3390/jcm14051679.
The coronal plane alignment of the knee (CPAK) classification categorises nine phenotypes based on constitutional limb alignment and joint line obliquity and can be used in healthy and arthritic knees. In total knee arthroplasty surgery, some morphological variables in planes other than the coronal plane are particularly interesting. One example is the distal femoral rotation. Our study aimed to search for relationships between phenotypes based on CPAK classification and distal femoral rotation. Data from 622 cases in 535 osteoarthritic patients who underwent primary total knee arthroplasty were retrospectively analysed. Computed tomography imaging was employed to ascertain the mechanical lateral distal femoral angle, the mechanical medial proximal tibial angle, and the distal femoral rotation (quantified using the condylar twist angle). The variables were perfectly uncorrelated according to the regression equations, with a Coefficient of Determination of 0.0608 for the condylar twist angle. Upon visualising the condylar twist angle function using a contour map or surface curves with low interpolation, it became evident that the data did not follow any discernible pattern. Employing ANOVA, we found some statistically significant differences between the distributions of the CPAK groups for the condylar twist angle (F = 5.81; < 0.001). Our study found no relevant relationships between coronal plane alignment, according to the CPAK classification, and the distal femoral rotation in the sample population studied. Perhaps the stratification of the CPAK groups (i.e., a purely arithmetical aspect) hides possible relationships between the coronal and the axial planes.
膝关节冠状面排列（CPAK）分类根据肢体结构排列和关节线倾斜度将九种表型进行了分类，可用于健康膝关节和患有关节炎的膝关节。在全膝关节置换手术中，冠状面以外平面的一些形态学变量特别值得关注。一个例子是股骨远端旋转。我们的研究旨在寻找基于CPAK分类的表型与股骨远端旋转之间的关系。对535例接受初次全膝关节置换术的骨关节炎患者的622例病例数据进行了回顾性分析。采用计算机断层扫描成像来确定机械性股骨外侧远端角、机械性胫骨内侧近端角以及股骨远端旋转（使用髁扭转角进行量化）。根据回归方程，这些变量完全不相关，髁扭转角的决定系数为0.0608。使用低插值的等高线图或表面曲线来可视化髁扭转角函数时，很明显数据没有遵循任何可识别的模式。采用方差分析，我们发现CPAK组在髁扭转角分布上存在一些统计学上的显著差异（F = 5.81；<0.001）。我们的研究在所研究的样本人群中未发现根据CPAK分类的冠状面排列与股骨远端旋转之间存在相关关系。也许CPAK组的分层（即纯粹的算术方面）掩盖了冠状面和轴面之间可能存在的关系。
