Characteristics of knees in the study according to whether there was prior change
| All | By KL grade change in the year before the index exam | By JSN change in the year before the index exam | |||
|---|---|---|---|---|---|
| Constant KL=2 | Incident OA | No JSN increase | JSN increase | ||
| 2037 knees (1562 subjects) | 1898 knees (1427 subjects) | 139 knees (135 subjects) | 1948 knees (1476 subjects) | 167 knees (146 subjects) | |
| Baseline age, year, mean (SD) | 61.8 (9.0) | 61.8 (9.0) | 61.3 (8.6) | 61.7 (9.0) | 62.3 (8.8) |
| Baseline BMI, kg/m2, mean (SD) | 29.4 (4.8) | 29.4 (4.8) | 29.3 (4.3) | 29.4 (4.8) | 28.7 (4.6) |
| N (%) female | 963 (61.7) | 869 (60.9) | 94 (69.6) | 904 (61.3) | 59 (68.6) |
| N (%) Whites | 1227 (78.6) | 1115 (78.2) | 112 (83.0) | 1150 (78.0) | 77 (89.5) |
| Baseline PASE, mean (SD) | 158.3 (82.0) | 158.6 (82.7) | 156.1 (74.5) | 158.5 (82.1) | 155.7 (82.1) |
| Baseline/12-month quadriceps strength,* mean (SD) | 325.8 (128.2) | 324.5 (128.0) | 343.0 (130.1) | 324.9 (128.3) | 337.2 (126.6) |
| Clinical centre | |||||
| A | 260 (16.7) | 246 (17.24) | 14 (10.4) | 250 (16.9) | 10 (11.6) |
| B | 317 (20.3) | 287 (20.11) | 30 (22.2) | 298 (20.2) | 19 (22.1) |
| C | 454 (29.1) | 420 (29.43) | 34 (25.2) | 427 (28.9) | 27 (31.4) |
| D | 388 (24.8) | 343 (24.04) | 45 (33.3) | 364 (24.7) | 24 (27.9) |
| E | 143 (9.2) | 131 (9.18) | 12 (8.9) | 137 (9.3) | 6 (7.0) |
| N (%) knee pain more than half the days of a month in the past 12 months at the index visit | 632 (31.2) | 584 (30.9) | 48 (34.8) | 601 (31.0) | 31 (35.2) |
| N (%) knee pain more than half the days of a month in the past 30 days at the index visit | 567 (28.0) | 5252 (27.8) | 42 (30.4) | 542 (27.9) | 25 (28.4) |
| Knee pain severity in the past 30 days, scale 0–10, mean (SD), at the index visit | 2.6 (2.7) | 2.6 (2.7) | 2.5 (2.6) | 2.6 (2.7) | 2.8 (2.7) |
*Quadriceps strength from baseline was used. If strength was not assessed at the baseline visit, we used the 12-month value.
BMI, body mass index; JSN, joint space narrowing; KL, Kellgren and Lawrence; OA, osteoarthritis; PASE, Physical Activity Survey for the Elderly.