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Table 2 Clinical characteristics at index date

From: Impact of oral osteoarthritis therapy usage among other risk factors on knee replacement: a nested case-control study using the Osteoarthritis Initiative cohort

  Knee replacement
Case (n = 218) Control (n = 540)
  (n = 204) (n = 537)
BMI ≥ 27 kg/m2, % (n) 75.0% (153) 70.6% (379)
WOMAC, median (IQR)
 Pain (0–20) 6.0 (4.0–9.0) 5.0 (3.0–8.0)
 Function (0–68) 22.2 (14.9–31.0) 18.0 (8.5–25.5)
 Stiffness (0–10) 3.0 (2.0–4.0) 3.0 (2.0–4.0)
 Total (0–98) 31.2 (21.8–43.0) 25.0 (13.0–37.0)
KOOS, median (IQR)
 Pain (0–100) 61.1 (47.2–72.2) 66.7 (55.6–79.3)
 Symptoms (0–100) 64.3 (50.0–78.6) 75.0 (58.9–85.7)
 QoL (0–100) 43.8 (31.3–56.3) 56.3 (43.8–68.8)
Kellgren-Lawrence grade, % (n)
 0 1.4% (3) 1.7% (9)
 1 3.7% (8) 3.7% (20)
 2 19.3% (42) 23.9% (129)
 3 31.6% (69) 29.8% (161)
 4 44.0% (96) 40.9% (221)
  (n = 211) (n = 524)
JSW (mm), median (IQR) 2.0 (0.8–4.6) 2.8 (1.1–4.6)
Cartilage volume (mm3), median (IQR) (n = 201) (n = 510)
 Global knee 11,037 (9127 - 13,634) 11,058 (9351 - 13,508)
 Medial compartment 5127 (3971 - 6482) 5219 (4176 - 6502)
 Lateral compartment 6028 (4864 - 7480) 6043 (4970 - 7265)
BML (n = 201) (n = 511)
 Global
  Median (IQR) 2.0 (0.6–4.4) 1.7 (0.4–3.8)
  BML ≥ 1%, % (n) 65.7% (132) 61.5% (314)
 Medial compartment
  Median (IQR) 0.014 (0.0–0.058) 0.021 (0.0–0.057)
  BML ≥ 1%, % (n) 34.9% (76) 42.2% (228)
 Lateral compartment
  Median (IQR) 0.005 (0.0–0.025) 0.0 (0.0–0.018)
  BML ≥ 1%, % (n) 23.9% (52) 20.7% (112)
  (n = 215) (n = 532)
Meniscal extrusion, % (n) 39.5% (85) 38.5% (205)
  1. Data shown are proportion of patients (%), number of patients (n), or median (interquartile range (IQR))
  2. BMI body mass index, BML bone marrow lesions, JSW joint space width, KOOS Knee injury and Osteoarthritis Outcome Score, QoL quality of life, WOMAC Western Ontario and McMaster Universities Osteoarthritis Index