title: Quantitative analysis of subchondral sclerosis of the tibia by bone texture parameters in knee radiographs: site-specific relationships with joint space width.
abstract: OBJECTIVE
  To determine the ability of radiographic bone texture (BTX) parameters to quantify subchondral tibia sclerosis and to examine clinical relevance for assessing osteoarthritis (OA) progression. We examined the relationship between BTX parameters and each of (1) location-specific joint space width (JSW) [JSW(x)] and minimum JSW (mJSW) of the affected compartment, and (2) knee alignment (KA) angle in knee radiographs of participants undergoing total knee arthroplasty (TKA).
  
  
  METHODS
  Digitized fixed-flexion knee radiographs were analyzed for run-length and topological BTX parameters in a subchondral region using an algorithm. Medial JSW(x) was computed at x=0.200, 0.225, 0.250 and 0.275 according to a coordinate system defined by anatomic landmarks. mJSW was determined for medial and lateral compartment lesions. KA angles were determined from radiographs using an anatomic landmark-guided algorithm. JSW measures and the magnitude of knee malalignment were each correlated with BTX parameters. Reproducibility of BTX parameters was measured by root-mean square coefficients of variation (RMSCV%).
  
  
  RESULTS
  Run-length BTX parameters were highly reproducible (RMSCV%<1%) while topological parameters showed poorer reproducibility (>5%). In TKA participants (17 women, 13 men; age: 66+/-9 years; body mass index (BMI): 31+/-6 kg m(-2); WOMAC: 41.5+/-16.1; Kellgren-Lawrence score mode: 4), reduced trabecular spacing (Tb.Sp) and increased free ends (FE) were correlated with decreased JSW after accounting for BMI, gender and knee malalignment. These relationships were dependent on site of JSW measurement.
  
  
  CONCLUSIONS
  High reproducibility in quantifying bone sclerosis using Tb.Sp and its significant relationship with JSW demonstrated potential for assessing OA progression. Increased trabecular FE and reduced porosity observed with smaller JSW suggest collapsing subchondral bone or trabecular plate perforation in advanced knee OA.
authors.affiliation: Department of Medical Sciences, McMaster University, Hamilton, ON, Canada. wongko@mcmaster.ca
authors.forename: A K O
authors.initials: AK
authors.lastname: Wong
authors.forename: K A
authors.initials: KA
authors.lastname: Beattie
authors.forename: P D
authors.initials: PD
authors.lastname: Emond
authors.forename: D
authors.initials: D
authors.lastname: Inglis
authors.forename: J
authors.initials: J
authors.lastname: Duryea
authors.forename: A
authors.initials: A
authors.lastname: Doan
authors.forename: G
authors.initials: G
authors.lastname: Ioannidis
authors.forename: C E
authors.initials: CE
authors.lastname: Webber
authors.forename: J
authors.initials: J
authors.lastname: O'Neill
authors.forename: J
authors.initials: J
authors.lastname: de Beer
authors.forename: J D
authors.initials: JD
authors.lastname: Adachi
authors.forename: A
authors.initials: A
authors.lastname: Papaioannou
mesh_terms: D000368:Aged; D015519:Bone Density / Q000502:physiology*; D002358:Cartilage, Articular / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography; D015203:Reproducibility of Results; D012598:Sclerosis / Q000000981:diagnostic imaging / Q000473:pathology; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology*