Relationship Between Knee Pain and Infrapatellar Fat Pad Morphology: A Within- and Between-Person Analysis From the Osteoarthritis Initiative

Arthritis Care Res (Hoboken). 2018 Apr;70(4):550-557. doi: 10.1002/acr.23326. Epub 2018 Mar 11.


Objective: Inflammation is known to be strongly associated with knee pain in osteoarthritis. The infrapatellar fat pad represents a potential source of proinflammatory cytokines. Yet the relationship between infrapatellar fat pad morphology and osteoarthritis symptoms is unclear.

Methods: Here we investigate quantitative imaging parameters of infrapatellar fat pad morphology between painful versus contralateral pain-free legs of subjects with unilateral knee pain and patients with chronic knee pain versus those of matched pain-free control subjects. A total of 46 subjects with strictly unilateral frequent knee pain and bilateral radiographic osteoarthritis (Kellgren/Lawrence grade 2/3) were drawn from the Osteoarthritis Initiative. Further, 43 subjects with chronic knee pain over 4 years and 43 matched pain-free controls without pain over this period were studied. Infrapatellar fat pad morphology (volume, surface area, and depth) was determined by manual segmentation of sagittal magnetic resonance images.

Results: No significant differences in infrapatellar fat pad morphology were observed between painful versus painless knees of persons with strictly unilateral knee pain (mean difference -0.7% (95% confidence interval [95% CI] -0.6, 0.9; P = 0.64) or between chronically painful knees versus matched painless controls (-2.1% [95% CI -2.2, 1.1]; P = 0.51).

Conclusion: Independent of the ambiguous role of the infrapatellar fat pad in knee osteoarthritis (a potential source of proinflammatory cytokines or a mechanical shock absorber), the size of the infrapatellar fat pad does not appear to be related to knee pain.

Trial registration: NCT00080171.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / diagnostic imaging*
  • Adipose Tissue / physiopathology
  • Aged
  • Arthralgia / diagnostic imaging*
  • Arthralgia / physiopathology
  • Case-Control Studies
  • Chronic Pain / diagnostic imaging*
  • Chronic Pain / physiopathology
  • Female
  • Humans
  • Magnetic Resonance Imaging*
  • Male
  • Middle Aged
  • Osteoarthritis, Knee / diagnostic imaging*
  • Osteoarthritis, Knee / physiopathology
  • Pain Measurement
  • Patellofemoral Joint / diagnostic imaging*
  • Patellofemoral Joint / physiopathology
  • Pilot Projects
  • Predictive Value of Tests

Associated data