Table 1.
Comparison of the demographics for the three bearing types included in this study
| Demographic | Ceramic-on-ceramic (n = 238) |
Metal-on-metal (n = 148) |
Polyethylene bearing (n = 1721) |
p value |
|---|---|---|---|---|
| Sex | ||||
| Female | 112/238 (47%)a | 75/148 (51%)b | 1011/1721 (59%) | < 0.001 |
| Male | 126/238 (53%) | 73/148 (49%) | ||
| Age at primary THA (years) Median (range) | 58 (15–86)d | 59 (15–86)e | 61 (14–97)f | 0.0072 |
| Time before revision (years) Median (range) | 3 (0.01–28)g | 4 (0.04–37)h | 13 (0–42)i | < 0.001 |
| Age at THA revision (years) Median (range) | 63 (16–91)j | 63 (22–91)k | 74 (20–104)l | < 0.001 |
| Diameter of bearing couple (mm) Median (range) | 32 (26–36)m | 32 (22–56)n | 28 (22–52)o | < 0.001 |
| Body mass index (kg/m2), median(range) | 26 (15–59) | 26 (15–44) | 26 (14–66) | 0.24 |
| Devane activity score (59 missing values) | ||||
| One | 13/234 (6%)p | 3/141 (2%)q | 161/1673 (10%)r | < 0.001 |
| Two | 50/234 (21%) | 39/141 (28%) | 655/1673 (39%) | |
| Three | 105/234 (45%) | 48/141 (34%) | 623/1673 (37%) | |
| Four | 55/234 (23%) | 44/141 (31%) | 196/1673 (12%) | |
| Five | 11/234 (5%) | 7/141 (5%) | 38/1673 (2%) | |
| Indication for primary THA (20 missing values) | 152/236 (64%)s | 97/146 (67%)t | 1080/1705 (63%)u | 0.0089 |
| Osteoarthritis Dysplasia | 18/236 (8%) | 18/146 (12%) | 230/1705 (14%) | |
| Inflammatory disease | 5/236 (2%) | 2/146 (1%) | 44/1705 (2%) | |
| Miscellaneous | 10/236 (4%) | 2/146 (1%) | 55/1705 (3%) | |
| Necrosis of the femoral head | 32/236 (14%) | 19/146 (13%) | 131/1705 (8%) | |
| Trauma | 19/236 (8%) | 8/146 (6%) | 165/1705 (10%) | |
Results are presented as number (%) for qualitative variables and as median (range) for quantitative variables; pairwise comparisons were performed using the Bonferroni procedure or the Dwass, Steel, Critchlow-Fligner multiple comparison procedure; a versus b: p = 1; a versus c: p = 0.0018; b versus c: p = 0.1656; d versus e: p = 0.9646; d versus f: p = 0.0182; e versus f: p = 0.1569; g versus h: p = 0.1928; g versus i: p < 0.0001; h versus i: p < 0.0001; j versus k: p = 0.8177; j versus l: p < 0.0001; k versus l: p < 0.0001; m versus n: p = 0.3513; m versus o: p < 0.0001; n versus o: p < 0.0001; p versus q: p = 0.2331; p versus r: p < 0.0001; q versus r: p < 0.0001; s versus t: p = 1; s versus u: p = 0.0249; t versus u: p = 0.2355.