Synovitis detected on magnetic resonance imaging and its relation to pain and cartilage loss in knee osteoarthritis
- Catherine L Hill1,
- David J Hunter2,
- Jingbo Niu2,
- Margaret Clancy2,
- Ali Guermazi3,
- Harry Genant3,
- Daniel Gale4,
- Andrew Grainger5,
- Philip Conaghan5,
- David T Felson2,4
- 1Rheumatology Unit, The Queen Elizabeth Hospital, Woodville, Australia
- 2Boston University Clinical Epidemiology Research and Training Unit, Boston, MA, USA
- 3Synarc, Inc, San Francisco, CA, USA and University of California San Francisco, San Francisco, CA, USA
- 4VA Boston Healthcare System, Boston, MA, USA
- 5Departments of Radiology and Rheumatology, Leeds Teaching Hospitals Trust & Leeds Primary Care Trust, Leeds, UK
- D T Felson, Boston University School of Medicine, A203, 80 E. Concord Street, Boston, MA 02118, USA;
- Accepted 19 April 2007
- Published Online First 9 May 2007
Objective: To examine the relationship between longitudinal fluctuations in synovitis with change in pain and cartilage in knee osteoarthritis.
Methods: Study subjects were patients 45 years of age and older with symptomatic knee osteoarthritis from the Boston Osteoarthritis of the Knee Study. Baseline and follow-up assessments at 15 and 30 months included knee magnetic resonance imaging (MRI), BMI and pain assessment (VAS) over the last week. Synovitis was scored at 3 locations (infrapatellar fat pad, suprapatellar and intercondylar regions) using a semiquantitative scale (0–3) at all 3 time points on MRI. Scores at each site were added to give a summary synovitis score (0–9).
Results: We assessed 270 subjects whose mean (SD) age was 66.7 (9.2) years, BMI 31.5 (5.7) kg/m2; 42% were female. There was no correlation of baseline synovitis with baseline pain score (r = 0.09, p = 0.17). The change in summary synovitis score was correlated with the change in pain (r = 0.21, p = 0.0003). An increase of one unit in summary synovitis score resulted in a 3.15-mm increase in VAS pain score (0–100 scale). Effusion change was not associated with pain change. Of the 3 locations for synovitis, changes in the infrapatellar fat pad were most strongly related to pain change. Despite cartilage loss occurring in over 50% of knees, synovitis was not associated with cartilage loss in either tibiofemoral or patellofemoral compartment.
Conclusions: Change in synovitis was correlated with change in knee pain, but not loss of cartilage. Treatment of pain in knee osteoarthritis (OA) needs to consider treatment of synovitis.
Supported by NIH AR47785.
Competing interests: None declared.
- magnetic resonance imaging
- visual analogue scale
- whole-organ magnetic resonance imaging score