Table 4.
Baseline characteristics of patients undergoing primary THA for continuous variables
| Geneva registry Switzerland (N = 1,023) | FORCE-TJR United States (N = 4,647) | Mean difference (95% CI) | P-value**** | |
|---|---|---|---|---|
| Age at operation, mean [±SD] | 68.2 [±12.9] | 64.6 [±10.7] | 3.6 (2.8; 4.3) | 0.000 |
| Preoperative BMI, mean [±SD]* | 26.87 [±5.0] | 29.12 [±5.7] | -2.2 (-1.9; -2.6) | 0.000 |
| Mean age in each BMI category, [±SD] | ||||
| <25 | 68.61 [±14.7] | 66.35 [±11.5] | 2.3 (3.7; 0.8) | 0.000 |
| 25–29.9 | 68.55 [±12.2] | 65.42 [±10.4] | 3.1 (1.9; 4.3) | 0.000 |
| 30–34.9 | 67.24 [±11.0] | 63.82 [±10.1] | 3.4 (1.8; 5.1) | 0.000 |
| ≥35 | 65.68 [±8.8] | 61.17 [±9.8] | 4.5 (2.1; 7.0) | 0.000 |
| Preoperative scores, mean [±SD] | Mean difference | |||
| (95% CI)/Effect size | ||||
| WOMAC pain | 39.51 [±18.5] | 47.81 [±19.8] | -8.3 (-9.8; -6.8)/0.43 | 0.000 |
| WOMAC function | 40.21 [±19.5] | 44.24 [±19.2] | -4.0 (-5.6; -2.5)/0.21 | 0.000 |
| SF-12 Physical Component Summary | 33.39 [±7.9] | 31.26 [±8.5] | 2.1 (1.5; 2.8)/0.26 | 0.000 |
| SF-12 Mental Component Summary | 43.91 [+11.7] | 49.97 [±12.6] | -6.1 (-7.0; -5.1)/0.5 | 0.000 |
*BMI was available for 6,452 TKAs (96.6%) from FORCE-TJR
**In the Geneva cohort information on education was routinely collected only since 2012
***FORCE-TJR collects RA versus OA
****Pearson chi2 tests were used for categorical variables, and two-sample Wilcoxon rank-sum (Mann-Whitney) tests were used for continuous variables