Table 1.
Univariate analysis
| Category | Uncemented implant (n = 4319) | Cemented implant (n = 2179) | p value* |
|---|---|---|---|
| Followup (years), mean (SD) | 5.6 (4.8) | 10.5 (5.3) | < 0.0001 |
| Age (years), mean (SD) | 62.1 (12.1) | 71.9 (10.2) | < 0.0001 |
| Cost of implant, mean (SD) | $6074 ($1313) | $4491 ($1646) | < 0.0001 |
| Sex | |||
| Male | 2055 (48%) | 742 (34%) | < 0.0001 |
| Female | 2264 (52%) | 1437 (66%) | |
| Age categories (years) | |||
| < 55 | 1119 (26%) | 141 (6%) | < 0.0001 |
| 55–70 | 2051 (47%) | 699 (32%) | |
| > 70 | 1149 (27%) | 1339 (61%) | |
| Procedural timeframe | |||
| 1991–1998 | 513 (12%) | 1079 (50%) | < 0.0001 |
| 1999–2004 | 946 (22%) | 787 (36%) | |
| 2005–2011 | 2860 (66%) | 313 (14%) | |
| Primary diagnosis | |||
| Osteoarthritis | 3940 (91%) | 1958 (90%) | 0.07 |
| Aseptic necrosis | 201 (5%) | 104 (5%) | |
| Other | 178 (4%) | 117 (5%) | |
| Stem revision reason | |||
| Loosening related to wear/osteolysis | 5 (8%) | 5 (7%) | NA† |
| Aseptic loosening | 11 (17%) | 45 (63%) | |
| Periprosthetic fracture | 20 (31%) | 3 (4%) | |
| Infection | 7 (11%) | 5 (7%) | |
| Dislocation | 5 (8%) | 10 (14%) | |
| Failure of bone ingrowth | 12 (19%) | 0 (0%) | |
| Mechanical failure/breakage | 1 (2%) | 1 (1%) | |
| Instability | 0 (0%) | 2 (3%) | |
| Pain | 2 (3%) | 0 (0%) | |
| Other | 1 (2%) | 0 (0%) | |
* Probability values were calculated using the Wilcoxon rank-sum test for continuous variables and the Pearson’s chi-square test for categorical variables; † too many categories to calculate a meaningful p value; NA = not applicable.