What is the primary function of the knee?

• A. Impact absorption and adaptation
• B. Weight transfer to the LE
• C. Shortening of the lower limb to allow foot clearance during the swing phase
• D. Joint stabilization during high-speed running

Answer: (B)

The knee’s primary function is transferring body weight to the lower extremity. In standing and walking, it acts as a central load-bearing joint that passes forces from the femur through the tibia and onward to the ground, while allowing flexion and extension to accommodate movement. This weight-transfer role underpins efficient gait and upright posture, with ligaments and the menisci helping stabilize and distribute the load. The other aspects—shock absorption, limb shortening for foot clearance, or stabilization during high-speed running—are important features that accompany knee function but do not define its main purpose.