In closed-chain knee extension (femur on tibia), what happens at the tibiofemoral joint?

In closed-chain knee extension (femur on tibia), what happens at the tibiofemoral joint?

• A. The femoral condyles roll anteriorly and slide posteriorly
• B. The femoral condyles roll posteriorly and slide anteriorly
• C. The tibia rolls anteriorly and slides posteriorly
• D. The menisci become displaced anteriorly

Answer: (A)

In closed-chain knee extension, the femur moves on the tibia, and the femoral condyles are the convex moving surfaces on the concave tibial plateau. According to the convex-on-concave rule, roll and glide occur in opposite directions. As the knee extends, the femoral condyles roll anteriorly on the tibia while simultaneously sliding posteriorly. This pattern maintains joint congruity through the extension movement. The other descriptions either flip the directions or describe movement of the tibia itself (open-chain) or a non-kinematic event like meniscal displacement, which isn’t the primary tibiofemoral arthrokinematic pattern during closed-chain extension.

In closed-chain knee extension, the femur moves on the tibia, and the femoral condyles are the convex moving surfaces on the concave tibial plateau. According to the convex-on-concave rule, roll and glide occur in opposite directions. As the knee extends, the femoral condyles roll anteriorly on the tibia while simultaneously sliding posteriorly. This pattern maintains joint congruity through the extension movement.

The other descriptions either flip the directions or describe movement of the tibia itself (open-chain) or a non-kinematic event like meniscal displacement, which isn’t the primary tibiofemoral arthrokinematic pattern during closed-chain extension.