Demographic characteristics and pain | Controls (n = 10) | RA (n = 41) | Test, statistic, significance | |
Age, yrs.: | mean (SD), range | 55.6 (8.0), 42–72 | 55.3 (11.5), 25–77 | Student’s t-test, t = 0.07, p = 0.283 |
Sex: | % female (n) | 70.0% (7/10) | 78.0% (32/41) | Chi-sq., χ2 = 0.29, p = 0.591 |
VAS pain, mm: | median (IQR), range | 0.0 (0.0–0.3), 0–2 | 36.0 (18.0–70.0), 8–95 | Mann-Whitney U, z = 4.87, p < 0.001 |
Functional impairment and foot deformity | Controls (n = 10) | RA (n = 41) | ||
FISIF score: | median (IQR) | 1 (0–3) | 13 (11–15) | Mann-Whitney U, z = 4.82, p < 0.001 |
FISAP score: | median (IQR) | 0 (0–0) | 16 (11–23) | Mann-Whitney U, z = 4.89, p < 0.001 |
Platto forefoot index: | median (IQR) | 2 (1–2) | 9 (5–10) | Mann-Whitney U, z = 3.71, p < 0.001 |
Gait velocity, cm/s: | mean (95% CI) | 117.78 (4.67) | 92.70 (4.38) | Student’s t-test, t = 3.92, p = 0.001 |
Subluxation: | % patients (n) | 0.0% (0/10) | 70.7% (29/41) | Chi-sq., χ2 = 16.40, p < 0.001 |
% joints (n) | 0.0 (0/40) | 61.6% (101/164) | ML log rega | |
Callus: | % patients (n) | 60.0% (6/10) | 43.9% (18/41) | Chi-sq., χ2 = 0.84, p = 0.360 |
% joints (n) | 17.5% (7/40) | 17.7% (29/164) | ML log reg, z = −0.08, p = 0.939 | |
Plantar plate pathology: | % patients (n) | 20.0% (2/10) | 85.4% (35/41) | Chi-sq., χ2 = 17.24, p < 0.001 |
% joints (n) | 5.0% (2/40) | 46.6% (76/163) | ML log reg; z = 3.57, p < 0.001 | |
Peak pressure, kPa: Peak pressure, kPa: | max per patient median (IQR) individual joint geometric mean | 563.3 (454.6–773.8) 323.75 | 746.7 (555.0–1145.0) 399.41 | Mann-Whitney U, z = 1.90, p = 0.058 ML lin reg; z = −1.66, p = 0.096 |