Table 1.
Two-year mean clinical evaluation scores
| Treatment group | Metal-on-polyethylene | Metal-on-metal, 28 mm | Metal-on-metal, 36 mm | Intergroup p value* (MOP and MOM28) | Intergroup p value* (MOP and MOM36) | Intergroup p value* (MOM28 and MOM 36) |
|---|---|---|---|---|---|---|
| Harris hip | 96 ± 6 | 92 ± 10 | 95 ± 9 | 0.057 | 0.246 | 0.274 |
| WOMAC | 89 ± 19 | 88 ± 11 | 88 ± 18 | 0.052 | 0.674 | 0.129 |
| SF-12 PCS | 51 ± 9 | 44 ± 12 | 48 ± 11 | 0.033 | 0.281 | 0.224 |
| SF-12 MCS | 55 ± 6 | 58 ± 7 | 56 ± 7 | 0.015 | 0.279 | 0.262 |
*Intergroup p value = difference in mean evaluation scores at the 2-year postoperative interval between the metal-on-polyethylene group and each of the metal-on-metal groups and between the two metal-on-metal groups using the Mann-Whitney test; means and standard deviations are shown; no differences between groups were seen for any of the clinical evaluations at 2-year followup with the exception of the WOMAC (0.052), SF-12 physical (0.033) and mental scores (0.015) between the metal-on-polyethylene (MOP) group and the 28-mm metal-on-metal (MOM) group.