Version of the osteoarthritic knee.

Version of normal and osteoarthritic knees is evaluated by computed tomography in this study. Version of the knee is defined as the static rotation of the tibia with respect to the femur in full knee extension. It is measured as the difference between the transverse axes of the femoral condyles and tibia. The average knee version, or external rotation of the tibia with respect to the femur across the normal knee, was 0 degree. Version of the osteoarthritic knee was 5 degrees. Rotation of the tibia with respect to the femur across the extended osteoarthritic knee is a relationship that will affect the placement of components in total knee arthroplasty. This relationship should be addressed in alignment instrumentation and technique to avoid component malalignment in total knee arthroplasty.