Table 5.
Severity of dysplasia and head-neck offset characteristics
| Variables | Femoral version (5°–20°) (n = 17) | Relative femoral retroversion (≤ 5°) (n = 7) | Excessive femoral anteversion (> 20°) (n = 26) | p value |
|---|---|---|---|---|
| Alpha angle* (degrees; mean ± SD) | ||||
| 9:00 | 37 ± 3 | 37 ± 2 | 35 ± 3 | 0.37 |
| 10:30 | 35 ± 3 | 36 ± 4 | 35 ± 3 | 0.89 |
| 12:00 | 39 ± 3 | 38 ± 4 | 39 ± 3 | 0.64 |
| 1:30 | 49 ± 6 | 51 ± 7 | 49 ± 6 | 0.92 |
| 3:00 | 47 ± 8 | 48 ± 4 | 42 ± 7 | 0.06† |
| Maximum alpha angle* (degrees; mean ± SD) | 53 ± 6 | 55 ± 7 | 52 ± 6 | 0.64 |
| Maximum alpha angle location* (o’clock; mean ± SD) | 2:15 ± 30 minutes | 2:00 ± 45 minutes | 2:00 ± 45 minutes | 0.67 |
| Femoral head-neck offset* (mm; mean SD) | ||||
| 12:00 | 10 ± 2 | 10 ± 1 | 9 ± 1 | 0.42 |
| 1:30 | 7 ± 1 | 7 ± 1 | 6 ± 1 | 0.43 |
| 3:00 | 8 ± 1 | 8 ± 2 | 8 ± 2 | 0.94 |
| Femoral head-neck offset ratio (mean ± SD) | ||||
| 12:00 | 0.21 ± 0.03 | 0.21 ± 0.02 | 0.20 ± 0.02 | 0.49 |
| 1:30 | 0.15 ± 0.03 | 0.14 ± 0.02 | 0.14 ± 0.03 | 0.30 |
| 3:00 | 0.17 ± 0.03 | 0.17 ± 0.03 | 0.17 ± 0.04 | 0.98 |
Probability values based on univariate comparisons between relative femoral retroversion and excessive femoral anteversion hips; * alpha angle, head-neck offset, and head-neck offset ratio measured according to the clock position; †analysis of variance p = 0.04; post hoc Tukey testing not significant (p values 1 versus 2 p = 1.00, 2 versus 3 p = 0.06, 1 versus 3 p = 0.21).