Bi-cruciate stabilized total knee arthroplasty restores the native knee alignments better than conventional posterior stabilized total knee arthroplasty

Introduction This study aimed to compare the differences in the radiological, clinical, and functional outcomes and the estimated restoration rate of native knee alignment between total knee arthroplasty (TKA) with bi-cruciate stabilized (BCS) and posterior stabilized (PS) design. Materials and methods This retrospective study included consecutive patients between 2020 and 2021 who underwent TKA. The patients were divided into two groups (group I, Journey II BCS TKA [106 knees]; group II, Persona PS TKA [106 knees]) after 1:1 propensity score matching. We assessed the radiologic parameters in the coronal (constitutional hip-knee-ankle angle [aHKA] and joint line obliquity [JLO]), sagittal, and axial planes. The femoral roll-back, clinical, and functional outcomes were evaluated. The joint perception was evaluated using the forgotten joint score (FJS). Results Group I had a higher restoration rate of aHKA and JLO postoperatively (P = 0.039 and P < 0.001). The changes in the patella tendon angle, posterior overhang of the femur, patella tilt angle, and patella lateral shift in group II were larger than those in group I (P < 0.001). Group I was superior in the range of motion (ROM) (P = 0.004), femoral roll-back (P < 0.001), and FJS (P = 0.021). Conclusions BCS TKA demonstrated better restoration of native knee alignments, including constitutional coronal knee alignment and native sagittal knee alignment, and lesser patella lateral shift than conventional PS TKA. In addition, BCS TKA was superior in ROM, femoral roll-back, and joint perception, which were associated with the degree of restoration of constitutional coronal knee alignment. Level of evidence Level III, retrospective cohort study.