Tibiofemoral rotation during sit-to-stand activity after TKA

The objective of this study was to describe how tibiofemoral internal/external rotation varies in patients after total knee arthroplasty (TKA) when compared with control participants during a sit-to-stand (STS) maneuver. Motion analysis was used to measure internal/external knee rotation during STS in the control and TKA groups. Fourteen participants were included in the study. Six patients with 7 TKA knees (6 posterior stabilized and 1 cruciate-retaining TKA) were compared with 8 control participants with 8 knees from the current authors\u27 laboratory database. Participants performed 3 STS maneuvers, and the average internal/external rotation of the femur with respect to the tibia was compared. All control participants and 2 TKA participants had internal rotation of the femur with respect to the tibia, whereas 4 TKA participants had external rotation, and 1 had no rotation during STS. Further investigation into the surgical and patient-and implant-related factors that affect this resulting reverse kinematic profile seems to be warranted