Aims The Coronal Plane Alignment of the Knee (CPAK) classification has been developed to predict individual variations in inherent knee alignment. The impact of preoperative and postoperative CPAK classification phenotype on the postoperative clinical outcomes of total knee arthroplasty (TKA) remains elusive. This study aimed to examine the effect of postoperative CPAK classification phenotypes (I to IX), and their pre- to postoperative changes on patient-reported outcome measures (PROMs). Methods A questionnaire was administered to 340 patients (422 knees) who underwent primary TKA for osteoarthritis (OA) between September 2013 and June 2019. A total of 231 patients (284 knees) responded. The -Knee Society Score 2011 (KSS 2011), Knee injury and Osteoarthritis Outcome Score-12 (KOOS-12), and Forgotten Joint Score-12 (FJS-12) were used to assess clinical outcomes. Using preoperative and postoperative anteroposterior full-leg radiographs, the arithmetic hip-knee-ankle angle (aHKA) and joint line obliquity (JLO) were calculated and classified based on the CPAK classification. To investigate the impact on PROMs, multivariable regression analyses using stepwise selection were conducted, considering factors such as age at surgery, time since surgery, BMI, sex, implant use, postoperative aHKA classification, JLO classification, and changes in aHKA and JLO classifications from preoperative to postoperative. Results The preoperative and postoperative CPAK classifications were predominantly phenotype I (155 knees; 55%) and phenotype V (73 knees; 26%), respectively. The change in the preoperative to postoperative aHKA classification was a significant negative predictive factor for KOOS-12 and FJS-12, while postoperative apex proximal JLO was a significant negative predictive factor for KSS 2011 and KOOS-12. Conclusion In primary TKA for OA, preoperative and postoperative CPAK phenotypes were associated with PROMs. Alteration in varus/valgus alignment from preoperative to postoperative was recognized as a negative predictive factor for both KOOS-12 and FJS-12. Moreover, the postoperative apex proximal JLO was identified as a negative factor for KSS 2011 and KOOS-12. Determining the target alignment for each preoperative phenotype with reproducibility could improve PROMs.

中文翻译：

---

术前和术后冠状面膝关节对齐分类及其对全膝关节置换术临床结果的影响。


目的 膝关节冠状平面对齐 （CPAK） 分类已被开发用于预测固有膝关节对齐的个体变化。术前和术后 CPAK 分类表型对全膝关节置换术 （TKA） 术后临床结果的影响仍然难以捉摸。本研究旨在检查术后 CPAK 分类表型 （I 至 IX） 及其术前至术后变化对患者报告结果测量 （PROM） 的影响。方法 对 2013 年 9 月至 2019年6月期间接受骨关节炎 （OA） 初次 TKA 的 340 例患者 （422 例膝关节） 进行了问卷调查。共有 231 名患者 （284 个膝关节） 做出回应。采用 -膝关节协会评分 2011 （KSS 2011） 、膝关节损伤和骨关节炎结局评分 12 （KOOS-12） 和遗忘关节评分 12 （FJS-12） 评估临床结局。使用术前和术后前后全腿 X 线片，根据 CPAK 分类计算和分类算术髋-膝-踝角 （aHKA） 和关节线倾斜度 （JLO）。为了研究对 PROM 的影响，使用逐步选择进行了多变量回归分析，考虑了手术年龄、手术后时间、BMI、性别、植入物使用、术后 aHKA 分类、JLO 分类以及 aHKA 和 JLO 分类从术前到术后的变化等因素。结果 术前和术后 CPAK 分类主要为表型 I （155 个膝关节;55%） 和表型 V （73 个膝关节;26%）。 术前和术后 aHKA 分类的变化是 KOOS-12 和 FJS-12 的显著阴性预测因素，而术后心尖近端 JLO 是 KSS 2011 和 KOOS-12 的显著阴性预测因素。结论 在 OA 的原发性 TKA 中，术前和术后 CPAK 表型与 PROM 相关。从术前到术后内翻/外翻排列的改变被认为是 KOOS-12 和 FJS-12 的阴性预测因素。此外，术后根尖近端 JLO 被确定为 KSS 2011 和 KOOS-12 的阴性因素。确定具有可重复性的每种术前表型的靶标对齐可以改善 PROM。