Fig. 4
a–h Pro-inflammatory mediator evolution after two cold applications in the synovial fluid in the microcrystal-induced arthritis subgroup (N = 28; ice: N = 19). The synovial fluid of all cryotherapy-treated patients suffering from microcrystal-induced arthritis (N = 27 including 18 ice-treated patients) was analyzed just before the first cold application, then 24 h later (after two cold application). Data are presented as means ± SEM. Paired Wilcoxon-Mann-Whitney tests were performed. *p < 0.05, **p < 0.01, ***p < 0.001. H0: first evaluation (9 a.m., before the first cold application); H24: second evaluation (9 a.m., 24 h later, after the two cold applications); microcrystals: patients suffering from microcrystal-induced knee arthritis. Missing values were due to the fact that some cytokines and mediators could not be detected—or with out-of-range values—in some synovial fluid samples before and/or after cold applications (IL-6: N = 0; IL-1β: N = 2 in ice-treated patients (1 at H0, 1 at H24); TNF-α: N = 1 (1 CO2-treated patient both at H0 and H24); IL-17A: N = 0; VEGF: N = 0; NFkB-p65: N = 6 in ice + CO2-treated patients (3 at H0, 2 at H24, 1 CO2-treated patient at both H0 and H24), N = 3 in ice-treated patient (2 at H0, 1 at H24); NFkB-p65P: N = 6 in ice + CO2-treated patients (3 at H0, 2 at H24, 1 CO2-treated patient at both H0 and H24), N = 3 in ice-treated patient (2 at H0, 1 at H24); PG-E2: N = 6 in ice + CO2-treated patients (3 at H0, 2 at H24, 1 CO2-treated patient at both H0 and H24), N = 3 in ice-treated patient (2 at H0, 1 at H24))