In vivo determination of knee kinematics for Japanese subjects having either a low contact stress rotating platform or an anteroposterior glide total knee arthroplasty.

The objective of this study was to work with a consecutive series of patients having Hospital for Special Surgery scores higher than 90 to evaluate kinematic patterns, under in vivo conditions, for 20 Japanese subjects implanted with 2 different mobile-bearing (MB) total knee arthroplasties (TKAs). Femorotibial contact paths for the medial and lateral condyles were then determined using a computer-automated model-fitting technique. This present study has shown that kinematic patterns for subjects having 2 different MB TKA designs differed but were not statistically different. Subjects implanted with a rotating platform (RP) MB TKA experienced minimal anteroposterior (AP) motion and larger axial rotation (RP). Subjects implanted with an anterior glide MB TKA experienced both femoral rotation and femoral translation (AP glide). There was minimal variability in the kinematic patterns for subjects implanted with an RP, whereas subjects implanted with an AP glide experienced more variable kinematic patterns. Key words: total knee arthroplasty, in vivo, fluoroscopy, kinematics.