Department of Orthopaedics, General Hospital of Southern Theatre Command, Guangzhou, China.
Guangdong Key Lab of Orthopedic Technology and Implant Materials, Key Laboratory of Trauma & Tissue Repair of Tropical Area of PLA, Department of Orthopedics, General Hospital of Southern Theater Command of PLA, Guangzhou, China.
Orthop Surg. 2022 Dec;14(12):3340-3348. doi: 10.1111/os.13529. Epub 2022 Nov 8.
Understanding the morphology of the distal femur is essential for improving bone-implant match in total knee arthroplasty (TKA) and understanding the mechanisms behind knee kinematics. However, little is known about the asymmetry of the posterior condyles. Thus, this study aimed to thoroughly investigate asymmetries in sizes and shapes between the medial and lateral posterior condyles before and after femoral resections during TKA in osteoarthritic (OA) knees.
Three-dimensional femoral models of 74 OA knees were constructed using computed tomography images. The morphologic measurements of the posterior condyle pre- and post-simulated osteotomy for TKA included the radii of the posterior condyles fitted to a circle on the sagittal and axial planes of the femoral coordinate system, the inclination angle of the articular surface and resected surface, and the width and height of the resected surface. Differences in the data were assessed using Student's t-test, and correlations were evaluated using the Pearson product-moment correlation.
The radii of the medial posterior condyles fitted to the circle were, on average, 6 mm larger than those of the lateral condyles on the axial plane (p < 0.001) and 0.7 mm smaller than those of the lateral condyles on the sagittal plane (p = 0.046). The inclination angles of the medial and lateral posterior condyles on the axial plane were significantly different with both pre-simulated and post-simulated osteotomy, respectively (both p < 0.001). The resected plane of the lateral posterior condyles displaced opposite inclination directions between the distal and proximal portions. Neither heights or widths of the medial posterior condyles were significantly different from those of their lateral counterparts (both p > 0.107).
This study found asymmetrical inclination of the resected surface and coronal radii between the medial and lateral posterior condyles, which may relate to the posterolateral overhang of the lateral condyle after TKA and the progression of the knee OA. These findings provides valuable morphological information and may help improve the implant designs for TKA.
了解股骨远端的形态对于提高全膝关节置换术（TKA）中骨-植入物的匹配度以及理解膝关节运动学背后的机制至关重要。然而，对于后髁的不对称性知之甚少。因此，本研究旨在全面研究骨关节炎（OA）膝关节 TKA 前后股骨切除术后内外侧后髁大小和形状的不对称性。
使用 CT 图像构建了 74 例 OA 膝关节的三维股骨模型。TKA 模拟截骨前后后髁形态测量包括在股骨坐标系矢状面和轴面拟合的后髁半径、关节面和切除面的倾斜角以及切除面的宽度和高度。使用 Student's t 检验评估数据差异，使用 Pearson 积矩相关评估相关性。
在轴面，内侧后髁拟合圆的半径平均比外侧髁大 6mm（p<0.001），比矢状面的外侧髁小 0.7mm（p=0.046）。轴向平面上内外侧后髁的倾斜角在模拟截骨前后均有显著差异（均 p<0.001）。外侧后髁的切除平面在远端和近端之间有相反的倾斜方向。内侧后髁的高度和宽度与外侧髁无显著差异（均 p>0.107）。
本研究发现内外侧后髁的切除面和冠状半径存在不对称的倾斜，这可能与 TKA 后外侧髁的后外侧突出以及膝关节 OA 的进展有关。这些发现提供了有价值的形态学信息，可能有助于改善 TKA 的植入物设计。
