Comparison of OARSI and thickness measurements of articular cartilage, subchondral bone plate and calcified cartilage between healthy subjects and patients with osteoarthritis
| Healthy subjects | Patients with osteoarthritis | Δ Mean | P values | |||
| n | Mean (95% CI) | n | Mean (95% CI) | |||
| OARSI evaluation | ||||||
| Random surface sampling points (n)* | 15 | 61 (54 to 68) | 20 | 59 (54 to 65) | 2 (−7 to 10) | 0.695 |
| OARSI grade | 15 | 0.2 (0.1 to 0.4) | 20 | 2.4 (92.1 to 2.8) | 2.2 (1.8 to 2.6) | <0.001 |
| OARSI stage* | 15 | 2.1 (1.7 to 2.6) | 20 | 4.0 (4.0 to 4.0) | 1.9 (1.5 to 2.2) | <0.001 |
| OARSI score | 15 | 4.3 (2.7 to 6.9) | 20 | 20.9 (19.3 to 22.6) | 16 | <0.001 |
| Morphometric assessment of stage (%) | ||||||
| OARSI grade 0 | 15 | 67 (48 to 94) | 7 | 8 (3 to 24) | −61 (−75 to 46) | <0.001 |
| OARSI grade 1 | 15 | 15 (10 to 23) | 20 | 21 (14 to 31) | 7 (−1 to 16) | 0.271 |
| OARSI grade 2 | 8 | 5 (3 to 11) | 20 | 25 (21 to 30) | 19 (11 to 26) | <0.001 |
| OARSI grade 3 | 5 | 6 (2 to 19) | 20 | 12 (9 to 17) | 8 (2 to 13) | 0.073 |
| OARSI grade 4 | – | 20 | 11 (8 to 14) | – | – | |
| OARSI grade 5 | – | 17 | 8 (6 to 12) | – | – | |
| OARSI grade 6 | – | 10 | 9 (5 to 16) | – | – | |
| Thickness (µm) | ||||||
| Articular cartilage (ThAC) | ||||||
| OARSI grades 0–6 | 15 | 1425 (1310 to 1549) | 20 | 1116 (976 to 1277) | −277 (−443 to 111) | 0.003 |
| OARSI grade ≤3† | 15 | 1425 (1310 to 1551) | 20 | 1464 (1323 to 1620) | 58 (−159 to 275) | 0.564 |
| OARSI grade ≥4‡ | – | 20 | 264 (182 to 383) | – | – | |
| OARSI grade 0* | 15 | 1448 (1325 to 1570) | 7 | 1640 (1243 to 2037) | 193 (−93 to 478) | 0.297 |
| OARSI grade 1 | 15 | 1381 (1160 to 1645) | 20 | 1525 (1350 to 1722) | 135 (−195 to 464) | 0.317 |
| OARSI grade 2 | 8 | 1523 (1163 to 1995) | 20 | 1441 (1259 to 1650) | −91(−606 to 423) | 0.664 |
| OARSI grade 3* | 5 | 1251 (786 to 1717) | 20 | 1265 (1080 to 1450) | 14 (−391 to 419) | 0.944 |
| OARSI grade 4* | – | 20 | 584 (437 to 731) | – | – | |
| OARSI grade 5 | – | 6 | 56 (14 to 224) | – | – | |
| OARSI grade 6 | – | – | – | – | ||
| Subchondral bone plate (ThSCB) | ||||||
| OARSI grades 0–6 | 15 | 248 (185 to 340) | 20 | 376 (318 to446) | 103 (30 to 176) | 0.019 |
| OARSI grade ≤3† | 15 | 276 (225 to 339) | 20 | 252 (205 to 308) | −24 (−109 to 62) | 0.515 |
| OARSI grade ≥4*‡ | – | 20 | 665 (550 to 781) | – | – | |
| OARSI grade 0 | 15 | 270 (215 to 339) | 7 | 216 (123 to 381) | −28 (−204 to 148) | 0.326 |
| OARSI grade 1 | 15 | 248 (188 to 328) | 20 | 200 (151 to 266) | −48 (−175 to 80) | 0.272 |
| OARSI grade 2* | 8 | 236 (54 to 418) | 20 | 275 (228 to 322 | 39 (−82 to 162 | 0.636 |
| OARSI grade 3 | 5 | 307 (140 to 220) | 20 | 314 (252 to 391) | −15 (−158 to 187) | 0.925 |
| OARSI grade 4 | – | 20 | 446 (355 to 559) | – | – | |
| OARSI grade 5* | – | 17 | 875 (757 to 992) | – | – | |
| OARSI grade 6* | – | 10 | 870 (691 to 1049) | – | – | |
| Calcified cartilage (ThCC) | ||||||
| OARSI grades 0–6 | 15 | 132 (113 to 155) | 20 | 159 (144 to 177) | 26 (6 to 45) | 0.036 |
| OARSI grade ≤3† | 15 | 132 (113 to 155) | 20 | 187 (164 to 214) | 57 (23 to 91) | 0.001 |
| OARSI grade ≥4‡ | – | 20 | 93 (71 to 122) | – | – | |
| OARSI grade 0 | 15 | 131 (112 to 152) | 7 | 153 (111 to 209 | 24 (−30 to 790 | 0.269 |
| OARSI grade 1 | 15 | 111 (77 to 160) | 20 | 202 (168 to 242) | 82 (28 to 1307) | 0.005 |
| OARSI grade 2 | 8 | 186 (129 to 269) | 20 | 174 (145 to 208) | −17 (−113 to 78 | 0.703 |
| OARSI grade 3* | 5 | 177 (137 to 219) | 20 | 183 (144 to 223) | 6 (−74 to 85) | 0.815 |
| OARSI grade 4 | – | 20 | 145 (125 to 168) | – | – | |
| OARSI grade 5 | – | 13 | 65 (37 to 113) | – | – | |
| OARSI grade 6 | – | 3 | 189 (1 to 583) | – | – | |
Data are presented as geometric mean and (95% CI). Statistical significance was found using Student’s t-test. P<0.05 was considered significant.
*Data that were normally distributed without being log transformed are presented as arithmetic mean (95%CI).
†OARSI grade ≤3 represents areas without loss of articular cartilage thickness.
‡OARSI grade ≥4 represents areas with loss of articular cartilage thickness.
AC, articular cartilage; CC, calcified cartilage; OARSI, Osteoarthritis Research Society International; SCB, subchondral bone.