title: Kinematic comparison between mobile-bearing and fixed-bearing inserts in NexGen legacy posterior stabilized flex total knee arthroplasty.
abstract: Femoral component rollback and tibial rotation were evaluated using lateral radiographs taken during passive knee flexion under fluoroscopy in NexGen Legacy Posterior Stabilized Flex (Zimmer, Warsaw, Ind) total knee arthroplasties (TKAs; 30 with mobile insert and 26 with fixed insert). Measured maximal flexion angle demonstrated no significant differences. Femoral component rollback was observed predominantly in TKAs with fixed insert in more than 45 degrees flexion and correlated with maximal flexion angle in each group. Tibial internal rotation was more significant in TKAs with mobile insert in maximal flexion. However, tibial internal rotation from 90 degrees to maximal flexion, which demonstrated correlation with maximal flexion angle in each group, did not show significant difference. The kinematic differences between 2 inserts seemed to have little relevance to the maximal flexion angle.
authors.affiliation: Department of Orthopaedic Surgery, Osaka Rosai Hospital, Osaka, Japan.
authors.forename: Kenrin
authors.initials: K
authors.lastname: Shi
authors.forename: Kenji
authors.initials: K
authors.lastname: Hayashida
authors.forename: Naoya
authors.initials: N
authors.lastname: Umeda
authors.forename: Kengo
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Hideo
authors.initials: H
authors.lastname: Kawai
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007717:Knee / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D011859:Radiography