Table 1.
Characteristics of study participantss (N = 4115)
| Characteristics | Values |
|---|---|
| Baseline | |
| Age, mean (s.d.), years | 61.2 (9.1) |
| Female, n (%) | 2383 (57.9) |
| BMI, mean (s.d.), kg/m2 | 28.6 (4.8) |
| Knee joint effusion volume, median (IQR), ml | 5.0 (3.2–8.5) |
| KL grade | |
| 0 (n = 1369) | 3.9 (2.8–5.5) |
| 1 (n = 663) | 4.3 (3.0–6.3) |
| 2 (n = 1102) | 5.4 (3.5–8.9) |
| 3 (n = 723) | 7.7 (4.8–14.9) |
| 4 (n = 258) | 15.8 (9.5–24.9) |
| Intra-articular steroid injection in the past 6 months, n (%) | 50 (1.22) |
| Knee injury in the past 12 months, n (%) | 42 (1.03) |
| Change | |
| Change in knee effusion volume over 1 year, ml (n = 3867), mean (s.d.; range) | 0.1 (5.5; −58.8–62.3) |
| Annual % cartilage volume loss over 4 years (n = 3138) | |
| Medial compartment, mean (s.d.; range) | 1.01 (1.62; −37.45–13.14) |
| Lateral compartment, mean (s.d.; range) | 0.97 (1.26; −8.61–8.82) |
| Progression of radiographic OA over 4 years, n (%) | 448 (14.5) |
| Baseline KL grade | |
| 0 (n = 1097) | 83 (7.6) |
| 1 (n = 555) | 108 (19.5) |
| 2 (n = 911) | 130 (14.3) |
| 3 (n = 534) | 127 (23.8) |
| Total knee replacement over 6 years, n (%) | 186 (4.5) |
| Baseline KL grade | |
| 0 (n = 1369) | 3 (0.2) |
| 1 (n = 663) | 4 (0.6) |
| 2 (n = 1102) | 30 (2.7) |
| 3 (n = 723) | 74 (10.2) |
| 4 (n = 258) | 75 (29.1) |
IQR: interquartile range.