Sahbat Yavuz, Gulagaci Firat, Mabrouk Ahmed, Karam Karam Mark, Jacquet Christophe, Ollivier Matthieu, Argenson Jean-Noël A
Institute of Movement Sciences, Sainte-Marguerite Hospital, Aix-Marseille University, Marseille, France.
Institute of Movement Sciences, Sainte-Marguerite Hospital, Aix-Marseille University, Marseille, France; Department of Trauma and Orthopaedic Surgery, Mid Yorkshire Teaching Hospitals, Yorkshire, UK.
J Arthroplasty. 2025 Jun;40(6):1508-1515.e1. doi: 10.1016/j.arth.2024.11.041. Epub 2024 Nov 23.
The applicability of the coronal plane alignment of the knee (CPAK) classification for unicompartmental knee arthroplasty (UKA) is not yet clear. The current study aimed to address the following questions: 1) what is the distribution of the CPAK classification among patients who underwent medial UKA? and 2) what would be the clinical outcomes for patients whose coronal alignment and joint line obliquity have either changed or been maintained postoperatively?
This retrospective study involved 325 patients treated with fixed-bearing medial UKA between 2017 and 2019 following a kinematic alignment strategy and using cemented resurfacing implants. Long-leg standing radiographs were utilized for all preoperative and postoperative measurements. There were two independent observers who measured the alignment parameters. The patient's CPAK classification diagram was subsequently created. At the last follow-up, patients' outcomes were assessed using the clinical scores.
The CPAK type 1 was the most prevalent type among 150 (46.1%) patients. Postoperatively, the most common CPAK type was type 2. In comparison to the preoperative distribution, there was a decrease in the prevalence of Types 1 and 4 in the postoperative distribution, whereas an increase in the distribution of all other types was noted. A total of 203 patients (62.4%) experienced CPAK classification change postoperatively, of which 122 patients (37.5%) maintained their original preoperative CPAK classification (P = 0.003). At a mean follow-up of 66.1 months (range, 54 to 75), implant survival (P = 0.9) and all clinical scores were similar between the CPAK Maintained and Changed groups (P > 0.05 for all).
The use of UKA may alter the preoperative CPAK distribution in more than half of the patients. Following UKA, a maintained coronal alignment and joint line obliquity do not have an impact on either patient-reported outcomes or implant survival.
IV, retrospective cohort series.
膝关节冠状面排列（CPAK）分类在单髁膝关节置换术（UKA）中的适用性尚不清楚。本研究旨在解决以下问题：1）接受内侧UKA的患者中CPAK分类的分布情况如何？2）术后冠状面排列和关节线倾斜度发生改变或保持不变的患者的临床结局如何？
本回顾性研究纳入了2017年至2019年间采用运动学对线策略并使用骨水泥型表面置换植入物进行固定平台内侧UKA治疗的325例患者。所有术前和术后测量均使用长腿站立位X线片。由两名独立观察者测量对线参数。随后创建患者的CPAK分类图。在最后一次随访时，使用临床评分评估患者的结局。
CPAK 1型是150例（46.1%）患者中最常见的类型。术后，最常见的CPAK类型是2型。与术前分布相比，术后分布中1型和4型的患病率降低，而其他所有类型的分布均增加。共有203例患者（62.4%）术后发生CPAK分类改变，其中122例患者（37.5%）维持其术前原始CPAK分类（P = 0.003）。平均随访66.1个月（范围54至75个月）时，CPAK维持组和改变组之间的植入物生存率（P = 0.9）和所有临床评分均相似（所有P>0.05）。
使用UKA可能会改变超过半数患者的术前CPAK分布。UKA术后，冠状面排列和关节线倾斜度的维持对患者报告的结局或植入物生存率均无影响。
IV，回顾性队列系列研究。
