Prevalence of knee synovitis on ultrasonography in subjects with painful knee OA
| Ultrasonographic knee synovitis* | p Value† | |||
|---|---|---|---|---|
| Absent | Present | |||
| *Knee synovitis was defined as “present” if synovial thickness was ⩾4 mm with diffuse or nodular appearance. †p Values refer to comparisons between subgroups with or without synovitis (Student’s t test for quantitative variables and χ2 test for qualitative variables). | ||||
| Total number of subjects, No (%) | 500 (83.3) | 100 (16.7) | ||
| Synovial thickness (mm) | <0.0001 | |||
| Mean (SD) | 1.3 (1.5) | 5.8 (3.0) | ||
| Median (range) | 1 (0–19) | 5 (4–29) | ||
| Appearance of synovial tissue, No (%) | <0.0001 | |||
| Absent | 278 (55.6) | 0 (0) | ||
| Nodular | 75 (15.0) | 56 (56.0) | ||
| Diffuse | 147 (29.4) | 44 (44.0) | ||
| Maximal effusion depth (mm) | <0.0001 | |||
| Mean (SD) | 3.4 (4.5) | 6.9 (3.9) | ||
| Median (range) | 2.7 (0–20) | 6.1 (0–71) | ||