Table 2.
Alignment of the total joint arthroplasty including the tibial and femoral components
| Control group | Introduction group | P value (Control vs Introduction) | Follow-up group | P value (Control vs Follow-up) | Test | |
| Tibial AP-alignment, mean (95%CI) | 88.5 (88.1-88.9) | 88.5 (88.1-88.9) | 0.68 | 88.5 (88.1-88.8) | 1.0 | Mann-Whitney U test |
| Outliers, n (%) | 11 (14.7) | 10 (13.3) | 0.81 | 10 (16.1) | 0.81 | χ2 |
| Femoral AP-alignment, mean (95%CI) | 96.0 (95.5-96.5) | 95.4 (95.0-95.8) | 0.06 | 95.6 (95.2-96.0) | 0.22 | Unpaired T-test |
| Outliers, n (%) | 21 (28) | 14 (18.7) | 0.18 | 11 (17.7) | 0.16 | χ2 |
| Post-operative TFA, mean (95%CI) | 4.4 valgus (3.8-5.0) | 3.8 valgus (3.3-4.4) | 0.16 | 4.2 valgus (3.6-4.8) | 0.62 | Unpaired T-test |
| Outliers, n (%) | 25 (33.3) | 26 (34.7) | 0.86 | 23 (37.1) | 0.65 | χ2 |
| Medial Tibial Overhang, n (%) | 5 (6.7) | 8 (10.7) | 0.38 | 6 (9.7) | 0.52 | χ2 |
| Lateral Tibial Overhang, n (%) | 6 (8.0) | 7 (9.3) | 0.77 | 4 (6.5) | 0.73 | χ2 |
| Tibial Slope, mean (95%CI) | 88.8 (88.2-89.4) | 85.1 (84.4-85.8) | < 0.0001 | 84.9 (84.2-85.5) | < 0.0001 | Unpaired T-test |
| Outliers, n (%) | 21 (28.0) | 13 (17.3) | 0.12 | 12 (19.4) | 0.24 | χ2 |
| Femoral Flexion (FF), mean (95%CI) | 86.2 (85.3-87.0) | 88.2 (87.8-88.7) | < 0.0001 | 88.2 (87.8-88.6) | < 0.0001 | Unpaired T-test |
| Outliers, n (%) | 44 (58.7) | 28 (37.3) | 0.009 | 16 (25.8) | < 0.0001 | χ2 |
For AP alignment femoral and tibial components, < 90 degrees correspond to varus placement and > 90 degrees correspond to valgus placement. Outliers were found based on intervals for optimal alignment of the components[13]. For normally distributed data, in accordance with Shapiro Wilk-test, kurtosis, skewness and histogram inspection mean values are presented and p-value calculated using the unpaired T-test. Otherwise Mann-Whitney U test was applied. P values for categorical data is calculated using Pearsons Chi-squared (χ2) test. 95%CI: 95 % Confidence interval; TFA: Tibio-femoral angle.