Kinematic Comparison Between Mobile-Bearing and Fixed-Bearing Inserts in NexGen Legacy Posterior Stabilized Flex Total Knee Arthroplasty

Knee stability before and after total and unicondylar knee replacement: In vivo kinematic evaluation utilizing navigation

“…We found that this mobile bearing TKA influenced the pattern of tibial axial rotation during flexion, while the amount of rotation was preserved. Although we considered only a few cases, our findings agree with those of Shi et al, 6 who found more significant tibial internal rotations in TKAs with mobile inserts in maximal flexion and by Delport et al, 7 who described that mobile bearing posterior stabilized knee replacements reproduce internal tibial rotation more closely during flexion than fixed bearing posterior stabilized.…”

“…[1][2][3][4] Most current knowledge about kinematics of the osteoarthritic (OA) and reconstructed knees comes from anatomical investigations and postoperative radiographic analyses. [5][6][7][8][9][10][11] Unicondylar knee arthroplasty (UKA) should preserve kinematics of the knee before reconstruction, while total knee arthroplasty (TKA) seems to substantially change the joint kinematics. 4,9,12,13 However, outcomes should be related to the specific prosthetic design and other surgical variables.…”

Is High-Flexion Total Knee Arthroplasty a Valid Concept? Bilateral Comparison With Standard Total Knee Arthroplasty

“…Internal rotation of tibia is also essential in deep knee flexion, and it is observed during deep flexion in normal knee opposite to "screw-home" movement of full extension [22]. Shi et al [38] evaluated femoral rollback and tibial internal rotation in different bearings of high-flexion PS design knees. They found that femoral rollback and tibial internal rotation correlated with maximum flexion angle.…”

Low-Contact-Stress Knee Arthroplasty: Past History or Ahead of Time?

“…Their group sizes were smaller, but implant design and surgeon factors were similar. [33][34][35][36][37][38] At this point, it is important to realize that the terms "mobile bearing" or "rotating platform" are not synonymous for "low contact stress." Kinematic variances between RP designs may depend on the extent of congruency between the bearing uppersurface and femoral component.…”

“…Condylar congruency in the Sigma knee (DePuy Synthes) was described in one study in terms of "tibiofemoral contact area" (400 mm 2 in the MB vs 200 mm 2 in the FB design). 33 Another study with Performance knees 34 (Zimmer Biomet, Warsaw, Indiana) mentioned "more concavity in both the sagittal and coronal plane," and in a study with NexGen knees 35 (Zimmer Biomet), it was noted that the "articulating radii" were different (1:1.05 in MB and 1:1.07 in FB). A uniform measure of condylar congruency would be practical to compare results and classify on authenticity in relation to the low-contact-stress concept.…”