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Anterior Cruciate Ligament Transection and Synovial Fluid Lavage in a Rodent Model to Study Joint Inflammation and Posttraumatic Osteoarthritis

Anterior Cruciate Ligament Transection and Synovial Fluid Lavage in a Rodent Model to Study Joint Inflammation and Posttraumatic Osteoarthritis

Published on: September 2, 2025

Varus and neutral coronal knee phenotypes dominate globally: insights from a systematic review and meta-analysis of

Bernard de Geofroy¹, Ammar Ghabi¹, Rayan Fairag²

¹Laveran Military Hospital, 34 Boulevard Laveran, 13013 Marseille, France.

|October 25, 2025

Abstract

Background:

The Coronal Plane Alignment of the Knee(CPAK) classification provides a reproducible framework for describing native coronal alignment and is increasingly used to guide personalized strategies in total knee arthroplasty (TKA). This systematic review and meta-analysis synthesizes the global distribution of CPAK phenotypes, stratified by osteoarthritis (OA) status, age, ethnicity, and region.

Methods:

A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines. Embase, PubMed/MEDLINE, and CENTRAL were searched for studies reporting CPAK classifications in healthy or osteoarthritic adult knees between February 2021 and January 2025. Eligible studies applied radiographic assessment and the original 9-type CPAK system. Pooled prevalence estimates were calculated with a random-effects model. Subgroup analyses were performed by OA status, geography, age, and ethnicity.

Results:

Thirty-three studies (32,543 knees) were included. CPAK Type 1 was the most common phenotype (31.5 %), followed by Type 2 (26.4 %). In osteoarthritic cohorts, Type 1 predominated (35.4 %), while in healthy cohorts, Type 2 was more frequent (22.9 %). Geographic variation was observed: Asian populations mainly showed Type 1, whereas Caucasian populations more often displayed Type 2. Age-stratified analysis revealed Type 2 was most frequent in younger cohorts (<40 years, 36.3 %), while Type 1 dominated after 40 years (34.4 %).

Conclusion:

This review provides the first global synthesis of CPAK distribution, highlighting variability shaped by OA status and demographic factors. The predominance of Type 1 in osteoarthritic knees and Type 2 in healthy individuals supports personalized alignment strategies. However, CPAK remains limited to the coronal plane and does not include sagittal or axial parameters essential for TKA planning.

Level Of Evidence:

Level III, systematic review and meta-analysis.

Keywords:

Alignment Knee Joint Knee Osteoarthritis Phenotype Total Knee Arthroplasty

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