Table 3.
Pre- and postoperative radiographic data
| Parameters | Protrusio group | Control group | p value* | p value† | p value‡ | p value§ | ||
|---|---|---|---|---|---|---|---|---|
| Preoperative | Postoperative | Preoperative | Postoperative | |||||
| Lateral center-edge angle (degrees) [52] | 51 ± 10 (28–71) | 40 ± 6 (30–65) | 28 ± 5 (18–39) | 24 ± 6 (10–44) | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| Acetabular index (degrees) [46] | −12 ± 6 (−21 to 4) | −7 ± 6 (−21 to 5) | 4 ± 5 (−8 to 17) | 8 ± 6 (−5 to 25) | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| Extrusion index (percent) [24] | 4 ± 7 (−13 to 21) | 13 ± 5 (−3 to 22) | 22 ± 5 (12–32) | 27 ± 6 (11–39) | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| ACM angle (degrees) [4, 13] | 45 ± 4 (36–53) | 45 ± 5 (37–55) | 44 ± 4 (33–55) | 44 ± 6 (34–56) | 0.529 | 0.037 | 0.125 | 0.112 |
| Crossover sign (percent positive) [28] | 25 | 26 | 73 | 35 | < 0.001 | 0.953 | < 0.001 | 0.386 |
| Retroversion index [44] (percent, of hips with positive crossover sign [28]) | 18 ± 11 (2–37) | 15 ± 8 (3–31) | 24 ± 15 (1–53) | 10 ± 10 (1–48) | 0.271 | 0.174 | < 0.001 | 0.185 |
| Posterior wall sign (percent positive) [28] | 3 | 16 | 85 | 87 | < 0.001 | 0.056 | 0.714 | < 0.001 |
| Sharp angle (degrees) [32] | 36 ± 4 (26–46) | 40 ± 4 (32–46) | 39 ± 3 (33–47) | 40 ± 3 (33–47) | 0.001 | < 0.001 | 0.008 | 0.721 |
| Ischial spine sign (percent) [14] | 24 | 21 | 46 | 48 | 0.033 | 0.690 | 0.828 | 0.005 |
| Caudocranial coverage (percent) | 93 ± 6 (75–100) | 86 ± 8 (63–100) | 80 ± 7 (64–93) | 73 ± 8 (51–91) | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| Anterior coverage (percent) | 40 ± 10 (22–61) | 34 ± 8 (17–46) | 24 ± 6 (11–37) | 17 ± 5 (8–35) | < 0.001 | < 0.001 | < 0.001 | < 0.001 |
| Posterior coverage (percent) | 72 ± 11 (48–95) | 63 ± 10 (43–92) | 41 ± 7 (27–64) | 41 ± 8 (22–64) | < 0.001 | < 0.001 | 0.621 | < 0.001 |
| Axial alpha angle (degrees) [26] | 53 ± 10 (40–79) | 45 ± 6 (34–58) | 62 ± 12 (37–85) | 46 ± 7 (30–65) | < 0.001 | < 0.001 | < 0.001 | 0.300 |
Ranges shown in parentheses; * preoperative between the two study groups; †pre- versus postoperative in the protrusio group; ‡pre- versus postoperative in the control group; §postoperative between the two study groups; ACM = angle of Idelberger and Frank.