Structural predictors of response to intra-articular steroid injection in symptomatic knee osteoarthritis

Table 1 Participant characteristics

Variable	MRI cohort	Radiograph cohort
Number	120^a	188
Age (years), mean (SD)	62.3 (10.3)	63.2 (10.3)
Female, frequency (%)	62 (51.7)	97 (51.6)
Number of days to follow-up appointment, median (IQR)	8.0 (7.0–14.0)	8.0 (7.0–14.0)
KOOS-pain subscale score (0–100)^b, median (IQR)	44.4 (36.1–55.6)	44.4 (36.1–55.6)
Pain on nominated activity, VAS_NA (0–10 cm)^c, median (IQR)	7.0 (5.5–7.7)^d	7.0 (5.6–8.1)^e
Pain in last week, VAS (0–10 cm)^c, median (IQR)	6.5 (4.7–7.8)^d	6.5 (4.9–8.0)^e
Responders to injection, at follow-up visit, frequency, (%)	85 (70.8)	137 (72.9)

MRI magnetic resonance imaging, SD standard deviation, IQR interquartile range, CI confidence interval, KOOS Knee Injury and Osteoarthritis Outcome Score, VAS visual analogue scale, VAS _NA VAS for pain during nominated activity. ^aThere were 109 baseline images available for assessment of Whole Organ Magnetic Resonance Imaging Score and 111 available for assessment of synovial tissue volume; ^bKOOS pain subscale is scored from 100 (no pain) to 0 (extreme pain); ^cVAS is scored from 0 cm (no pain) to 10 cm (pain as bad as you can imagine); ^dthere were 5 and 3 patients who did not complete their VAS_NA and VAS for pain in the last week, respectively; ^ethere were 8 and 4 patients who did not complete their VAS_NA and VAS for pain in last the week, respectively