Giurazza Giancarlo, Tanzilli Andrea, Franceschetti Edoardo, Campi Stefano, Gregori Pietro, Parisi Francesco Rosario, Paciotti Michele, Perricone Giovanni, Zampogna Biagio, Papalia Rocco
Operative Research Unit of Orthopeaedic and Trauma Surgery, Fondazione Policlinico Universitario Campus Bio-Medico, Roma, Italy.
Department of Medicine and Surgery, Research Unit of Orthopaedic and Trauma Surgery, Università Campus Bio-Medico di Roma, Roma, Italy.
Knee Surg Sports Traumatol Arthrosc. 2025 Oct;33(10):3592-3605. doi: 10.1002/ksa.12704. Epub 2025 May 19.
The coronal plane alignment of the knee (CPAK) classification is a nine-phenotype matrix based on limb alignment and joint line obliquity. This study aimed to provide a global overview of CPAK distribution, hypothesising significant geographic, osteoarthritic and sex-related variations.
A systematic literature search (Embase, Medline/PubMed and Cochrane Library) following PRISMA guidelines was conducted, utilising the search terms "Coronal Plane Alignment of the Knee" OR "CPAK". Studies considering image modalities other than long-leg radiographs were excluded. A random-effects meta-analysis of proportions was performed, and statistical significance was defined as p < 0.05.
A total of 38 studies comprising 46,966 knees were analysed. The most common phenotypes worldwide were CPAK I (33.1%), II (25.9%) and III (14.4%) in the osteoarthritic population and CPAK II (34.9%), I (21.5%) and III (19.3%) in the healthy population. Among osteoarthritic populations, CPAK type I was predominant in Europe (29.2%), Asia (41.9%) and America (33.6%), type II in Australia (32.6%) and type III in Africa (28.6%). In healthy populations, type II was predominant in Europe (42.8%) and Asia (35.3%), whereas type I was most common in South America (44.8%). Significant regional differences were observed among both osteoarthritic and healthy knees, and between osteoarthritic and healthy knees in individual countries. In Europe, significant sex differences were observed in the distribution of types I (39.1% M; 23.5% F) and III (11.4% M; 24.6% F) in the osteoarthritic population, and in the distribution of types I (26.7% M; 9.4% F), II (43.9% M; 34.4% F) and III (11.3% M; 20.6% F) in the healthy population. In Asia, significant sex differences were found for type III in osteoarthritic knees (6.3% M; 11.4% F).
CPAK distribution varies significantly as a function of geographic, osteoarthritic, and sex-related factors. A personalised approach to TKA may be desirable to better accommodate these differences.
Level IV.
膝关节冠状面排列（CPAK）分类是一种基于肢体排列和关节线倾斜度的九种表型矩阵。本研究旨在全面概述CPAK分布情况，假设存在显著的地域、骨关节炎和性别相关差异。
按照PRISMA指南进行系统的文献检索（Embase、Medline/PubMed和Cochrane图书馆），使用检索词“膝关节冠状面排列”或“CPAK”。排除考虑长腿X线片以外影像模态的研究。进行比例的随机效应荟萃分析，统计学显著性定义为p < 0.05。
共分析了38项研究，涉及46,966个膝关节。在骨关节炎人群中，全球最常见的表型是CPAK I（33.1%）、II（25.9%）和III（14.4%）；在健康人群中是CPAK II（34.9%）、I（21.5%）和III（19.3%）。在骨关节炎人群中，CPAK I型在欧洲（29.2%）、亚洲（41.9%）和美洲（33.6%）占主导，II型在澳大利亚（32.6%）占主导，III型在非洲（28.6%）占主导。在健康人群中，II型在欧洲（42.8%）和亚洲（35.3%）占主导，而I型在南美洲（44.8%）最常见。在骨关节炎膝关节和健康膝关节之间以及个别国家的骨关节炎膝关节与健康膝关节之间均观察到显著的区域差异。在欧洲，骨关节炎人群中I型（男性39.1%；女性23.5%）和III型（男性11.4%；女性24.6%）的分布以及健康人群中I型（男性26.7%；女性9.4%）、II型（男性43.9%；女性34.4%）和III型（男性11.3%；女性20.6%）的分布存在显著性别差异。在亚洲，骨关节炎膝关节中III型存在显著性别差异（男性6.3%；女性11.4%）。
CPAK分布因地域、骨关节炎和性别相关因素而有显著差异。全膝关节置换术采用个性化方法可能更有利于适应这些差异。
IV级。
