Department of Joint Surgery, PLA Army 80th Group Military Hospital, Weifang City, Shandong Province, China.
Sports Medicine Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.
Knee Surg Sports Traumatol Arthrosc. 2024 May;32(5):1264-1274. doi: 10.1002/ksa.12130. Epub 2024 Mar 15.
The aim of this study was to investigate the distribution of coronal plane alignment of the knee (CPAK) classification and functional knee phenotypes in a Chinese osteoarthritis (OA) population and to compare different lower limb alignment targets according to the distribution characteristics to find suitable total knee arthroplasty (TKA) bone cut strategies for the Chinese OA patients.
The computed tomography (CT) images were retrospectively collected and the three-dimensional (3D) models were reconstructed from 434 Chinese OA patients, including 93 males and 341 females, with a mean age of 66.4 ± 9.3 years. Femoral mechanical angle (FMA), tibial mechanical angle (TMA) and mechanical hip-knee-ankle angle (mHKA) were measured on the 3D models. Arithmetic hip-knee-ankle angle (aHKA) was calculated using FMA plus TMA, and joint line obliquity was calculated as 180 + TMA-FMA. The CPAK according to MacDessi and the functional knee phenotypes according to Hirschmann were performed. In addition, the suitable TKA bone cut strategies were explored according to the phenotypes and based on the characteristics of different alignment targets, such as mechanical alignment, anatomic alignment (AA), kinematic alignment, restricted KA (rKA) and adjusted MA (aMA). Statistical differences were determined using the independent-samples t-test or the two independent-samples Wilcoxon test, with p < 0.05 considered statistically significant.
The Chinese OA population showed a varus alignment tendency (mHKA = 172.1° ± 7.2°), to which the TMA was a major contributor (TMA = 84.7° ± 4.4° vs. FMA = 91.3° ± 3.2°). The mHKA was on average 3.9° more varus than the aHKA. A total of 140 functional knee phenotypes were found and 45.6% were concentrated in VAR3°-NEU0° to VAR3°-NEU0°. More than 70% of patients had different FMA and TMA phenotypes. There were 92.9% of CPAK distributed in types I to IV, with type I accounting for 53.9%. The FMA phenotypes were less changed if the aMA and rKA were chosen, and the TMA phenotypes were less changed if the AA and rKA were chosen.
Compared with the CPAK, the functional knee phenotypes were more suitable for the Chinese OA population with a wide distribution and a varus tendency, and it seemed more appropriate to choose aMA and rKA as TKA alignment targets for resection.
Level Ⅲ.
本研究旨在探讨膝关节冠状面对线（CPAK）分类和功能性膝关节表型在中国骨关节炎（OA）人群中的分布，并根据分布特征比较不同的下肢对线目标，以寻找适合中国 OA 患者的全膝关节置换术（TKA）截骨策略。
回顾性收集了 434 例中国 OA 患者的计算机断层扫描（CT）图像，并对其进行了三维（3D）重建，其中包括 93 例男性和 341 例女性，平均年龄为 66.4±9.3 岁。在 3D 模型上测量股骨机械角（FMA）、胫骨机械角（TMA）和机械髋-膝-踝角（mHKA）。通过 FMA 加 TMA 计算算术髋-膝-踝角（aHKA），关节线倾斜角计算为 180°+TMA-FMA。根据 MacDessi 进行 CP AK 分类，根据 Hirschmann 进行功能性膝关节表型分类。此外，根据表型并基于不同对线目标的特点，如机械对线、解剖对线（AA）、运动对线、限制 KA（rKA）和调整 MA（aMA），探讨了合适的 TKA 截骨策略。使用独立样本 t 检验或两独立样本 Wilcoxon 检验确定统计学差异，p<0.05 认为具有统计学意义。
中国 OA 人群表现出内翻对线倾向（mHKA=172.1°±7.2°），其中 TMA 是主要贡献因素（TMA=84.7°±4.4°比 FMA=91.3°±3.2°）。mHKA 平均比 aHKA 内翻 3.9°。共发现 140 种功能性膝关节表型，其中 45.6%集中在 VAR3°-NEU0°至 VAR3°-NEU0°。超过 70%的患者存在不同的 FMA 和 TMA 表型。CPAK 分布在 I 型至 IV 型，其中 I 型占 53.9%。如果选择 aMA 和 rKA，则 FMA 表型变化较小，如果选择 AA 和 rKA，则 TMA 表型变化较小。
与 CP AK 相比，功能性膝关节表型更适合中国 OA 人群，分布范围更广，内翻倾向更明显，似乎更适合选择 aMA 和 rKA 作为 TKA 对线目标进行切除。
III 级。
