Which KAFO feature describes a free motion joint?

• A. Allows the knee to flex/extend
• B. Locks the knee in extension
• C. Allows knee flexion in swing
• D. Adds bulk and may unlock inadvertently with posterior knee pressure

Answer: (A)

A free motion joint means the knee is not locked and can move in both directions in the sagittal plane. In a KAFO, this allows the knee to flex and extend during gait, closely mimicking how a natural knee works and enabling smoother walking.

That’s why the description “allows the knee to flex/extend” is the best match. If the knee were locked, motion would be prevented, which isn’t what a free motion joint provides. Saying the joint merely allows knee flexion in swing is more limited than the general capability of a free motion joint, since the joint should permit both flexion and extension throughout the gait cycle. The option about added bulk and potential inadvertent unlocking describes a different design concern (stability or unlocking mechanism) rather than the fundamental free motion capability.