title: Osteonecrosis of the tibial plateau: magnetic resonance imaging appearances with quantitation of lesion size and evidence of a pathogenesis of meniscal injury.
abstract: OBJECTIVE
  To determine the magnetic resonance (MR) imaging appearances of osteonecrosis of the tibial plateau and perform quantitative analysis of the extent of the necrotic area.
  
  
  METHODS
  Twenty-eight patients (34 knees) with osteonecrosis were retrospectively evaluated using MR imaging and other modalities where available. A computerized image analysis program that allowed quantification of the lesion size was used to obtain measurements of the extent of involvement, which were then incorporated into each stage of the disease.
  
  
  RESULTS
  The MR imaging findings of osteonecrosis of the tibial plateau included subchondral regions of abnormal signal intensity (n = 28), a double-line sign (n = 11), and fractures (n = 9). Meniscal tears and cartilage abnormalities were disclosed in the affected knee compartment with an equal frequency (n = 17). The size of the necrotic lesion varied among different stages of the disease as follows: 6.8% to 15.7% (stage I); 6.5% to 59.3% (stage II); 23.5% to 61.3% (stage III); and 34.3% to 75% (stage IV). The extent of involvement was greater in stage II than that in stage I (P < 0.001) and in stage IV than that in stage III (P < 0.05), whereas the extent of involvement in stage III was not significantly greater than that in stage II (P > 0.05).
  
  
  CONCLUSIONS
  The MR imaging characteristics of osteonecrosis of the tibial plateau are variable. The association of osteonecrosis at this site with meniscal tears and cartilage abnormalities has important implications for pathogenesis of the disease as it relates to physical stress. Quantification of the lesion size provides precise information for optimal staging of the disease.
authors.affiliation: Department of Radiology, University of California, San Diego, CA, USA.
authors.forename: Stavroula J
authors.initials: SJ
authors.lastname: Theodorou
authors.forename: Daphne J
authors.initials: DJ
authors.lastname: Theodorou
authors.forename: Niki J
authors.initials: NJ
authors.lastname: Agnantis
authors.forename: Panayotis N
authors.initials: PN
authors.lastname: Soucacos
authors.forename: Donald
authors.initials: D
authors.lastname: Resnick
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007718:Knee Injuries / Q000473:pathology; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology*; D008875:Middle Aged; D015588:Observer Variation; D010020:Osteonecrosis / Q000473:pathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013977:Tibia / Q000473:pathology*; D000070600:Tibial Meniscus Injuries; D055815:Young Adult