## 3 Results
### Preclinical Kinematics
Several studies have confirmed BCR-TKAs to have good AP stability throughout the range of knee flexion, regardless of the weight-bearing condition [45; 46]. Furthermore, using fluoroscopy while performing a deep knee bend activity, subjects having a BCR-TKA (n = 10) exhibited a more normal-like kinematic pattern in early and late flexion compared to CR-TKAs (n = 40) [47]. [PERSON] et al. matched kinematic data from BCR-TKA (Journey II XR, Smith and Nephew plc), UKA and healthy controls during squatting motion, under fluoroscopy [25]. Here, there was a lower extension angle of UKA knees than healthy and BCR-TKA knees (\(p<0.01\)) and lower flexion of BCR-TKA knees compared to healthy and UKA knees (\(p<0.01\)). In a separate study, it was found that BCR-TKA reduced femoral external rotation and AP translation with flexion. In addition, while preoperatively ACL forces correlated highly with AP translation of the femur during squatting, postoperatively only posterior cruciate ligament (PCL) forces correlated with AP translation of the lateral femoral condyle during squatting. These findings indicate that kinematic changes correlate with changes in cruciate ligament forces, thus underlining the lack of achieving native kinematics [48]. This has been supported by a validated computer tomography and fluoroscopic imaging system in 29 patients who underwent unilateral BCR-TKA. Again, during a single-leg deep lunge, BCR-TKAs showed significantly less posterior femoral translation during terminal flexion, compared with the contralateral native knee. Similarly, BCR-TKAs showed significantly less mean femoral rollback during sit-to-stand. BCR-TKAs also demonstrated significantly reduced internal rotation during high-flexion lunge and sit-to-stand. Even further, while [PERSON] et al. showed no statistical significant differences in AP translation as well as vurus rotation for BCR-TKA (Vanguard XP) (n = 30) compared to normal healthy knees during the stance phase, sagittal plane motion and tibofemoral articular contact characteristics including pivoting patterns were not fully restored in BCR-TKA patients during gait [49]. Together with the lack of restored sagittal plane motions and tibofemoral articular contact characteristics during gait, these findings suggest that BCR-TKA does not restore native tibofemoral articular contact kinematics [50]. [PERSON] et al. analyzed kinematic gait in females and males (15/14) after BCR-TKA implantation (Vanguard XP). The authors demonstrated significant increase in the KSS (58.1 \(\pm\) 11.8 preoperative to 86.6 \(\pm\) 16.7 postoperative, \(p<0.001\)). In a nine-month follow-up case-control study that compared BCR-TKA to PS-TKA and UKA in groups of twenty patients each, BCR-TKA showed a superior static balance ability on a single-leg test compared to the other techniques [51]. Motion and electromyography (EMG) data were also used to show that ACL retention led to altered muscle recruitment during downhill walking in 12 BCR-TKA subjects compared with 12 CR-TKA subjects; the authors concluded that BCR-TKA may offer some neuromuscular benefits for stabilizing the knee joint [52]. However, despite maintaining AP stability, asymmetric knee motion persisted in unilateral BCR-TKA patients during gait as assessed by a combined computer tomography and dual fluoroscopic imaging system in 29 patients. The results of this study suggested that the knee motion symmetry during gait was not restored in patients with unilateral BCR-TKA [46]. Finally, at a short-term follow-up of 6 weeks, in 15 knees that received BCR-TKA (Journey II XR), improved gait ability (walking time (\(p<0.01\)), number of steps (\(p<0.05\)), velocity (\(p<0.01\)) and stride length (\(p<0.01\)) was shown compared to those who received bicruciate-stabilized (BCS)-TKA [53].