title: Biochemical comparison of osteoarthritic knees with and without effusion.
abstract: BACKGROUND
  Several symptom-relieving interventions have been shown to be efficacious among osteoarthritis (OA) patients with knee effusion; however, not every symptomatic knee OA patient has clinical effusion. Results may be over-generalized since it is unclear if effused knees represent a unique pathological condition or subset compared to knees without effusion. The primary purpose of this study was to determine if biochemical differences existed between OA knees with and without effusion.
  
  
  METHODS
  The present cross-sectional study consisted of 22 volunteers (11 with knee effusion, 11 without knee effusion) with confirmed late-stage radiographic knee OA (Kellgren-Lawrence score ≥ 3). Synovial fluid samples were collected and analyzed using a custom multiplex enzyme-linked immunosorbent assay to determine eight specific biomarker concentrations (e.g., catabolic, anabolic).
  
  
  RESULTS
  Matrix metalloproteinase (MMP)-3, tissue inhibitor of MMPs (TIMP)-1, TIMP-2, and interleukin-10 were significantly higher in the knees with effusion than in the knees without effusion.
  
  
  CONCLUSIONS
  The biochemical differences that existed between knees with and without effusion provide support that OA subsets may exist, characterized by distinct biochemical characteristics and clinical findings (e.g., effusion).
authors: Department of Sports Medicine, West Chester University of Pennsylvania, 19383, USA.
authors: Nicole M
authors: NM
authors: Cattano
authors: Jeffrey B
authors: JB
authors: Driban
authors: Easwaran
authors: E
authors: Balasubramanian
authors: Mary F
authors: MF
authors: Barbe
authors: Mamta
authors: M
authors: Amin
authors: Michael R
authors: MR
authors: Sitler
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000737:chemistry / Q000378:metabolism; D005122:Exudates and Transudates / Q000737:chemistry / Q000502:physiology; D005260:Female; D006801:Humans; D016753:Interleukin-10 / Q000737:chemistry / Q000502:physiology; D008297:Male; D019278:Matrix Metalloproteinase 3 / Q000737:chemistry / Q000502:physiology; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D010865:Pilot Projects; D011859:Radiography; D013582:Synovial Fluid / Q000737:chemistry* / Q000201:enzymology / Q000502:physiology*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000737:chemistry / Q000502:physiology; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000737:chemistry / Q000502:physiology
chemical_list: D015415:Biomarkers; C508609:IL10 protein, human; C560822:TIMP1 protein, human; C560823:TIMP2 protein, human; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D016753:Interleukin-10; C511768:MMP3 protein, human; D019278:Matrix Metalloproteinase 3