Diagnostic properties of the Ottawa ankle rules for detecting fractures of the ankle and midfoot in acute ankle sprain *
| Category | Subcategory | NT | Sensitivity (95% CI) | Median specificity (IQR) | −LR | Post-test probability of a fracture† |
|---|---|---|---|---|---|---|
| *NT = number of 2×2 tables ; IQR = interquartile range. LR and CI defined in glossary. | ||||||
| †Post-test probability of a fracture after a negative result assuming a 15% prevalence of fractures. | ||||||
| All studies | 39 | 98% (96 to 99) | 32% (24 to 44) | 0.10 | 1.7% (1.1 to 2.8) | |
| Ankle | 15 | 98% (96 to 99) | 40% (28 to 48) | 0.08 | 1.4% (0.5 to 3.1) | |
| Foot | 10 | 99% (97 to 100) | 38% (25 to 70) | 0.08 | 1.4% (0.5 to 3.4) | |
| Type of assessment | Combined | 14 | 96% (94 to 99) | 26% (19 to 34) | 0.17 | 2.9% (1.7 to 5.0) |
| Children | 7 | 99% (98 to 100) | 27% (24 to 36) | 0.07 | 1.2% (0.5 to 3.1) | |
| Population | Adults | 32 | 97% (96 to 99) | 37% (22 to 46) | 0.11 | 1.9% (1.1 to 3.1) |
| <25th centile | 7 | 99% (98 to 100) | 48% (42 to 77) | 0.04 | 0.7% (0.4 to 1.9) | |
| 25th to 75th centile | 22 | 98% (96 to 99) | 30% (24 to 40) | 0.09 | 1.6% (0.9 to 2.8) | |
| Prevalence of fracture | >75th centile | 10 | 97% (94 to 99) | 27% (16 to 40) | 0.22 | 3.7% (1.7 to 8.3) |
| ≤48 | 5 | 100% (98 to 100) | 28% (25 to 32) | 0.06 | 1.1 (0.4 to 3.2) | |
| Time to referral (h) | >48 | 34 | 97% (96 to 99) | 37% (20 to 47) | 0.11 | 1.9 (1.2 to 3.1) |