Bicruciate-stabilized total knee arthroplasty shows kinematics closer to the native knee than cruciate-substituting total knee arthroplasty: a cadaveric study using the Journey II system.

BACKGROUND

To compare the kinematics of the native knee with those after cruciate-substituting (CS) and bicruciate-stabilized (BCS) total knee arthroplasty (TKA) within the same cadaveric specimens, focusing on rotation and anteroposterior (AP) translation.

METHODS

Ten fresh-frozen cadaveric knees with intact anterior cruciate ligaments underwent robotic-assisted TKA using a CS or BCS insert and navigation-based kinematic assessment. Changes in femoral rotation and AP positions during passive, non-weight-bearing knee flexion were evaluated in 30° increments of flexion. Kinematics was compared between the groups using repeated measures ANOVA with Bonferroni-adjusted post hoc comparisons.

RESULTS

Compared with the native knees, both TKA groups showed greater external rotation position during initial flexion. External rotation decreased between 0° and 30° flexion in both TKA groups, and decreased further between 90° and 120° flexion in only CS-TKA. AP translation patterns were similar between the TKA groups and the native knees. The AP position was significantly more anterior between 80° and 120° flexion after CS-TKA and significantly more anterior at 0°, 10° and between 70° and 90° flexion after BCS-TKA. Posterior translation was significantly decreased between 60° and 120° flexion after CS-TKA. Bicondylar rollback and medial pivot-like motion were qualitatively reproduced in both TKA groups.

CONCLUSIONS

In this cadaveric study, neither BCS-TKA nor CS-TKA fully restored native rotational kinematics in initial flexion, while CS-TKA failed to reproduce native rotational patterns in deep flexion. In contrast, BCS-TKA demonstrated AP translation patterns more comparable to the native knee. Native knee kinematics was more closely approximated by BCS-TKA than by CS-TKA.