title: Relationship between knee alignment and radiographic markers of osteoarthritis: a cross-sectional study from a Korean population.
abstract: OBJECTIVE
  The purpose of this paper was to investigate the relationship between static varus knee alignment and the radiographic markers of knee osteoarthritis (OA), including joint space narrowing (JSN) and Kellgren-Lawrence (K-L) grading scale.
  
  
  METHODS
  Knee alignment was measured by mechanical axis from weight-bearing anteroposterior (AP) radiographs of 251 symptomatic knees with radiological signs of OA (K-L grade ≥ 1). Linear correlation between knee varus alignment and variables, including joint space width (JSW) and K-L grades of tibiofemoral (TF) joint in extension or 45° flexion and patellofemoral (PF) joints were investigated. Multiple linear regression analyses were also performed to examine independent associations between varus knee alignment and JSW. Analysis of covariance (ancova) was performed to analyze the difference in knee alignment among K-L grade category groups adjusted for physical variables.
  
  
  RESULTS
  Varus knee alignment was negatively correlated with JSW of medial TF joint in extension AP (r = -0.460, P = 0.0001) and 45° flexion PA views (r = -0.476, P = 0.0001) and PF JSN (r = -0.168, P = 0.008). Multiple linear regression analysis adjusted for physical variables showed that the varus knee alignment was negatively associated with the JSW of medial TF joint in extension AP (P = 0.0001) and 45° flexion PA view (P = 0.0001). ancova adjusted for physical variables showed that knees in K-L grade 4 had significantly greater varus alignment than those in K-L grades 1-3 in AP (P = 0.0001), 45° flexion PA view (P = 0.0001), and PF joint (P = 0.0001~0.001).
  
  
  CONCLUSIONS
  Varus knee alignment is associated with the radiographic measures of knee OA severity.
authors.affiliation: Department of Orthopaedics, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Gun-Il
authors.initials: GI
authors.lastname: Im
authors.affiliation: Department of Orthopaedics, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Min-Kyu
authors.initials: MK
authors.lastname: Kim
authors.affiliation: Department of Orthopaedics, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Sung-Hyun
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059925:Anatomic Landmarks; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011237:Predictive Value of Tests; D056910:Republic of Korea; D012189:Retrospective Studies; D012720:Severity of Illness Index
keywords: K-L grading scale; joint space narrowing; knee alignment; osteoarthritis