Table 2. Characteristics of patients with developmental dysplasia of hip-dislocation by birth year.
| Birth year | 2011 (N = 810) |
2012 (N = 826) |
2013 (N = 731) |
Total (N = 2,367) |
| Female N (%) | 697 (86.0) | 716 (86.7) | 655 (89.6) | 2,068 (87.4) |
|
| ||||
| Affected side N (%) | ||||
| Right | 214 (26.4) | 212 (25.7) | 192 (26.3) | 618 (26.1) |
| Left | 460 (56.8) | 482 (58.4) | 438 (60.0) | 1,380 (58.3) |
| Bilateral | 74 (9.1) | 66 (8.0) | 48 (6.6) | 188 (7.9) |
| Unknown | 62 (7.7) | 66 (8.0) | 53 (7.3) | 181 (7.6) |
|
| ||||
| Born in cold monthsa N (%) | 374 (46.2) | 384 (46.5) | 362 (49.5) | 1,120 (47.3) |
| Incidence rate (/10,000 births) | ||||
| Born in cold monthsa | 11.1 | 15.2 | 10.9 | 11.1 |
| other months | 6.1 | 6.3 | 5.3 | 5.9 |
aCold months include November, December, January, and February.