Table 5.
Comparisons of the incidences of outliers among subgroups stratified by anatomical feature severity*
| Grade | Standard (n = 185) |
Navigated (n = 182) |
||||||
|---|---|---|---|---|---|---|---|---|
| Number | mTFA | cFPA | cTPA | Number | mTFA | cFPA | cTPA | |
| Femoral bowing angle | 0.006† | 0.022† | NS† | 0.007† | NA | NA | ||
| Medial bowing (≥ 0°) | 24 | 4 (16.7) | 2 (8.3) | 0 | 20 | 1 (5.0) | 0 | 0 |
| Mild lateral bowing (−5 ° ≤ < 0°) | 85 | 22 (25.9) | 0 | 4 (4.2) | 83 | 6 (7.2) | 0 | 0 |
| Severe lateral bowing (−10° ≤ < −5°) | 47 | 11 (23.4) | 5 (10.6) | 0/0 | 54 | 12 (22.2) | 0 | 0 |
| Very severe lateral bowing (< −10°) | 29 | 9 (31.0) | 3 (10.3) | 0 | 25 | 9 (36.0) | 0 | 0 |
| Femoral condylar orientation | 0.022† | NS† | NS† | < 0.001† | NA | NA | ||
| Valgus (≥ 0°) | 31 | 7 (22.6) | 1 (3.2) | 0 | 41 | 3 (7.3) | 0 | 0 |
| Mild varus (−3° ≤ < 0°) | 85 | 21 (24.7) | 3 (3.5) | 3 (3.5) | 95 | 13 (13.7) | 0 | 0 |
| Severe varus (< −3°) | 69 | 18 (26.5) | 6 (8.7) | 1 (1.4) | 46 | 12 (26.1) | 0 | 0 |
| Tibia plateau inclination | NS† | NS† | NS† | 0.009† | NA | NA | ||
| Valgus (≥ 0°) | 2 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| Mild varus (−3° ≤ < 0°) | 12 | 0 | 0 | 0 | 18 | 0 | 0 | 0 |
| Severe varus (−5° ≤ < −3°) | 23 | 5 (21.7) | 4 (17.4) | 1 (4.3) | 28 | 2 (7.1) | 0 | 0 |
| Very severe varus (< −5°) | 148 | 41 (27.7) | 6 (4.1) | 3 (2.0) | 135 | 26 (19.3) | 0 | 0 |
* Data are presented as numbers of knees with percentages in parentheses; †statistical significance (p value) was calculated using the chi square test or the Yates test; mTFA = mechanical tibiofemoral angle; cFPA = coronal femoral prosthesis alignment; cTPA = coronal tibial prosthesis alignment; NA = not applicable; NS = not significant.