Association of pain with site and grade of joint space narrowing. Odds ratios (OR) for pain are for different cut off levels of abnormality (for example, ⩾grade 1 v grade 0, etc)
| Site | Grade | OR for pain (95% CI) | Sensitivity (%) | Specificity (%) | Efficiency (%) |
|---|---|---|---|---|---|
| PFJ lateral | ⩾1 | 2.5 (1.5, 4.1) | 24.7 | 88.3 | 56.5 |
| ⩾2 | 4.4 (2.0, 9.7) | 14.6 | 96.3 | 55.5 | |
| ⩾3 | 12.9 (3.0, 55.0) | 10.8 | 91.1 | 50.9 | |
| PFJ medial | ⩾1 | 1.1 (0.6, 1.8) | 15.9 | 85 | 50.5 |
| ⩾2 | 1.2 (0.5, 2.7) | 5.4 | 95.3 | 50.4 | |
| ⩾3 | 0.9 (0.3, 3.1) | 2.0 | 97.7 | 49.9 | |
| Maximum PFJ grade | ⩾1 | 1.8 (1.2, 2.8) | 32.6 | 79.9 | 56.3 |
| ⩾2 | 2.7 (1.5, 4.9) | 17.9 | 92.5 | 55.2 | |
| ⩾3 | 4.1 (1.7, 9.5) | 12.1 | 96.7 | 54.4 | |
| TFJ lateral | ⩾1 | 0.8 (0.5, 1.3) | 12.9 | 84.1 | 48.5 |
| ⩾2 | 2.3 (0.4, 11.7) | 2.1 | 91.1 | 46.6 | |
| ⩾3 | 2-150 | 1.7 | 100 | 50.9 | |
| TFJ medial | ⩾1 | 2.1 (1.4, 3.1) | 38.9 | 76.6 | 57.8 |
| ⩾2 | 5.3 (2.2, 13.0) | 13.4 | 97.2 | 55.3 | |
| ⩾3 | 2-150 | 6.7 | 100 | 53.4 | |
| Maximum TFJ grade | ⩾1 | 1.9 (1.3, 2.8) | 48.5 | 67.2 | 57.9 |
| ⩾2 | 4.4 (2.0, 9.7) | 14.6 | 96.3 | 55.5 | |
| ⩾3 | 2-150 | 7.9 | 100 | 53.9 | |
| Maximum grade whole knee | ⩾1 | 1.8 (1.3, 2.7) | 62.3 | 53.1 | 57.7 |
| ⩾2 | 3.1 (1.8, 5.1) | 28.0 | 78.8 | 53.4 | |
| ⩾3 | 6.6 (2.9, 15.1) | 18.4 | 96.7 | 57.6 |
↵2-150 Denominator zero therefore unable to calculate simple odds ratios.