title: Hypointense signals in the infrapatellar fat pad assessed by magnetic resonance imaging are associated with knee symptoms and structure in older adults: a cohort study.
abstract: There are few clinical and epidemiological studies reporting the association between abnormal changes within the IPFP and knee osteoarthritic changes. This study aims to describe the associations between hypointense signals in the infrapatellar fat pad (IPFP) and knee structural change and symptoms in older adults.
  
  
  
  Participants (n = 874) were selected randomly from local community and followed up 2.7 years later (range 2.6-3.3 years). T1- or T2-weighted fat-suppressed magnetic resonance imaging (MRI) was assessed for IPFP hypointense signal, cartilage volume, cartilage defects, and bone marrow lesions (BMLs). Knee pain was assessed by self-administered Western Ontario and McMaster Osteoarthritis Index (WOMAC) questionnaire. Radiographic osteoarthritis was assessed using the OARSI atlas.
  
  
  
  Cross-sectionally, hypointense signals in the IPFP were significantly associated with a higher risk of knee cartilage defects at all sites, tibiofemoral BMLs and knee pain in multivariable analyses. Longitudinally, baseline signal abnormalities were significantly and positively associated with increases in knee cartilage defects (OR: 2.27, 95 % CI: 1.61-3.21), BMLs (OR: 1.91, 95 % CI: 1.39-2.62), and knee pain (OR: 1.36, 95 % CI: 1.05-1.76) in multivariable analyses. The associations with cartilage defects remained significant after adjustment for BMLs, but the associations with BMLs and knee pain decreased in magnitude or became non-significant after further adjustment for cartilage defects.
  
  
  
  Hypointense signals in the IPFP were associated primarily with increased knee cartilage defects and also with BMLs and knee symptoms in cross-sectional and longitudinal analyses, suggesting the abnormality represented by this signal has a potentially important role in osteoarthritis progression.
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, TAS, 7000, Australia.|Department of Orthopedics, 3rd Affiliated Hospital of Southern Medical University, Guangzhou, China.
authors.forename: Weiyu
authors.initials: W
authors.lastname: Han
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, TAS, 7000, Australia.
authors.forename: Dawn
authors.initials: D
authors.lastname: Aitken
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, TAS, 7000, Australia.|Arthritis Research Institute, 1st Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China.
authors.forename: Zhaohua
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Radiology, Royal Hobart Hospital, Hobart, TAS, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Halliday
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, TAS, 7000, Australia.
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, TAS, 7000, Australia.
authors.forename: Benny
authors.initials: B
authors.lastname: Antony
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
authors.forename: Flavia
authors.initials: F
authors.lastname: Cicuttini
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, TAS, 7000, Australia.
authors.forename: Graeme
authors.initials: G
authors.lastname: Jones
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, TAS, 7000, Australia. changhai.ding@utas.edu.au.|Arthritis Research Institute, 1st Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China. changhai.ding@utas.edu.au.|Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia. changhai.ding@utas.edu.au.
authors.forename: Changhai
authors.initials: C
authors.lastname: Ding
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging* / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D010146:Pain / Q000209:etiology
keywords: Bone marrow lesions; Cartilage defects; Infrapatellar fat pad; Osteoarthritis; Pain; Signal intensity