title: Mass effect and signal intensity alteration in the suprapatellar fat pad: associations with knee symptoms and structure.
abstract: OBJECTIVE
  To describe cross-sectional associations between mass effect or signal intensity alteration of the suprapatellar fat pad (SPFP) with knee symptoms and structure in older adults.
  
  
  METHODS
  A cross-sectional sample of 904 randomly selected subjects (mean 62.4 years, 49.9% female) was studied. T1- or T2-weighted fat suppressed magnetic resonance imaging (MRI) was used to assess mass effect or signal intensity alteration of SPFP, cartilage volume, cartilage defects, and bone marrow lesions (BMLs). Knee pain was assessed by self-administered Western Ontario McMaster Osteoarthritis Index (WOMAC) questionnaire. The Osteoarthritis Research Society International (OARSI) atlas was used to assess knee osteophyte, joint space narrowing (JSN) and radiographic osteoarthritis (ROA). Univariable and multivariable linear or logistic regression analyses were used to examine the associations.
  
  
  RESULTS
  After adjustment for confounders including age, sex, body mass index (BMI), disease status, tibial bone area and/or ROA, the presence of SPFP mass effect was significantly associated with any knee pain (OR: 2.39; 95% confidence interval (CI): 1.54, 3.70) and ROA (OR: 2.10; 95% CI: 1.33, 3.31) but not with cartilage volume, cartilage defects or BMLs. The presence of SPFP signal intensity alteration was significantly associated with any knee pain (OR: 1.90; 95% CI: 1.43, 2.53), ROA (OR: 1.83; 95% CI: 1.37, 2.45), any BMLs (OR: 1.55; 95% CI: 1.17, 2.06) but not with cartilage volume and cartilage defects. Significant associations with knee pain and BMLs were more evident in subjects with ROA. Presence of SPFP mass effect and/or signal intensity alteration combined was associated with any tibial cartilage defects (OR: 1.45; 95% CI: 1.04, 2.04).
  
  
  CONCLUSIONS
  SPFP mass effect and/or signal intensity alterations are deleteriously associated with knee pain, radiographic OA and BMLs in this cross-sectional study, suggesting that SPFP abnormalities may contribute to pain and structural abnormalities in the knee.
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia; Department of General Surgery, Yan'an Hospital of Kunming Medical University, Kunming Yan'an Hospital, Kunming, China.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia; Department of Orthopedics, 3rd Affiliated Hospital of Southern Medical University, Guangzhou, China.
authors.forename: W
authors.initials: W
authors.lastname: Han
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia; Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui, China.
authors.forename: F
authors.initials: F
authors.lastname: Pan
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia; Department of Orthopedics, 3rd Affiliated Hospital of Southern Medical University, Guangzhou, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Radiology, Royal Hobart Hospital, Hobart, Tasmania, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Halliday
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: X
authors.initials: X
authors.lastname: Jin
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Antony
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: F
authors.initials: F
authors.lastname: Cicuttini
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: G
authors.initials: G
authors.lastname: Jones
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia; Arthritis Research Institute, 1st Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China. Electronic address: Changhai.Ding@utas.edu.au.
authors.forename: C
authors.initials: C
authors.lastname: Ding
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging / Q000473:pathology*; D000368:Aged; D018771:Arthralgia / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology*; D001855:Bone Marrow Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D002357:Cartilage Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology*; D002358:Cartilage, Articular; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D054850:Osteophyte / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D010329:Patella / Q000000981:diagnostic imaging / Q000473:pathology*; D011446:Prospective Studies; D011859:Radiography
keywords: Osteoarthritis; Pain; Suprapatellar fat pad