Table 1.
Baseline characteristics of the study groups
| Clinical characteristics | Derivation set (n = 50) | Validation set (n = 20) | ||
|---|---|---|---|---|
| Mean | SD (range) | Mean | SD (range) | |
| Age (years) | 55.5 | 4.9 (39 to 64) | 57.6 | 4.3 (48 to 66) |
| Male (n) | 5 (12.1%) | 4(20%) | ||
| BMI | 26.1 | 3.2 (20.3 to 32.7) | 27.3 | 2.6 (20.5 to 31.9) |
| Left operation (n) | 30 (60%) | 12 (60%) | ||
| Preoperative G-KJLO (°) | − 0.8 | 2.4 (− 5.6 to 3.9) | − 3.3 | 2.63 (− 7.6 to 3.4) |
| Preoperative G-AJLO (°) | 8.4 | 3.3 (0.8 to 15) | 10.1 | 2.8 (3.1 to 12.1) |
| Preoperative TPI (°) | −5.7 | 2.0 (−10.5 to − 2.5) | −6.5 | 2.1 (− 9.8 to − 1.3) |
| Preoperative MTFA (°) | −7.7 | 2.1 (−12.9 to − 2.3) | −7.8 | 2.9 (−14 to − 2.6) |
| Preoperative TW (mm) | 73.1 | 4.4 (66.7 to 86) | 74.2 | 7.2 (65.9 to 89.4) |
| Preoperative TL (mm) | 340.5 | 21.7 (296 to 392) | 334.1 | 13.8 (308.1 to 349.4) |
| Preoperative FCO (°) | 1.7 | 2.0 (−2.6 to 5.6) | − 0.01 | 2.6 (−5 to 4) |
| Preoperative JSTA (°) | −3.6 | 2.2 (−9.6 to − 0.1) | − 2.6 | 1.8 (−6 to 0.3) |
| Preoperative FBA (°) | −0.07 | 3.1 (−7.4 to 7.1) | 1.37 | 2.3 (− 4.4 to 5.02) |
| Correction angle (°)a | 9.1 | 2.1 (7.0 to 15.2) | 9.5 | 3.7 (4.5 to 19.6) |
BMI Body mass index ratio, G-KJLO Knee joint line orientation relative to the ground, G-AJLO Ankle joint line orientation relative to the ground, TPI Tibia plateau inclination, MTFA Mechanical tibiofemoral angle, TW Tibial width, TL Tibial length, FCO Femoral condylar orientation, JSTA Joint space tilting angle, FBA Femoral bowing angle, SD Standard deviation
aCorrection angle was defined as the value derived from subtraction of preoperative TPI from postoperative TP