title: Clinical and ultrasonographic findings related to knee pain in osteoarthritis.
abstract: OBJECTIVE
  To determine clinical and sonographic factors associated with painful episodes in patients with knee osteoarthritis (OA).
  
  
  METHODS
  In this cross-sectional controlled study, patients with primary knee OA (ACR criteria) were prospectively placed into two groups. Group A: 81 patients with knee pain during physical activity >or=30 mm in visual analogue scale (VAS) for pain for at least 48 h prior to inclusion; Group B: 20 patients without knee pain from at least 1 month prior to inclusion. Clinical parameters, knee radiographic and ultrasonographic findings were collected. The sonographic study assessed joint effusion in the suprapatellar pouch, infrapatellar superficial and deep bursitis, meniscal lesions, anserine tendinobursitis, and Baker's cyst.
  
  
  RESULTS
  Group A patients tended to be older and heavier women than group B (P<0.05). The most frequent radiographic stage was III (57%) in group A, and I (35%) and II (35%) in group B, showing differences in the distribution of each radiographic stage (P<0.005). The most frequent ultrasonographic finding in group A was suprapatellar effusion (79%), and in group B it was meniscal lesions (40%). Ultrasonographic findings showed in group A a significant increase of suprapatellar effusion (P<0.001) and a tendency towards an increase of Baker's cyst (P=0.06). Suprapatellar effusion, Baker's cyst, and body mass index (BMI) were the factors associated with the appearance of pain after the logistic regression analysis.
  
  
  CONCLUSIONS
  Suprapatellar effusion, Baker's cyst, and higher BMI are more frequent and seem to be risk factors of painful flare in OA of the knee.
authors.affiliation: Department of Rheumatology, Hospital Universitario La Paz, Madrid, Spain. edemiguel.hulp@madrid.salud.org
authors.forename: E
authors.initials: E
authors.lastname: de Miguel Mendieta
authors.forename: T
authors.initials: T
authors.lastname: Cobo Ibáñez
authors.forename: J
authors.initials: J
authors.lastname: Usón Jaeger
authors.forename: G
authors.initials: G
authors.lastname: Bonilla Hernán
authors.forename: E
authors.initials: E
authors.lastname: Martín Mola
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010146:Pain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010147:Pain Measurement; D011446:Prospective Studies; D011859:Radiography; D014463:Ultrasonography