Which electrode arrangement is common for IFC targeting knee pain?

• A. Two electrodes above the knee
• B. Two electrodes below the knee
• C. Four-electrode configuration with diagonally crossing currents around the knee; one pair above the patella and one distal to the joint
• D. Single pair around the knee

Answer: (C)

Interferential current therapy relies on two medium‑frequency currents crossing inside the tissues to create a low‑frequency beat at the target area. For knee pain, using a four‑electrode setup that diagonally crosses around the knee places one current path above the patella and the other distal to the joint so the interference—and thus the beat frequency—occurs right at the knee region. This yields deeper, more focal stimulation and better pain modulation than a simple two‑electrode arrangement or a single pair around the knee, which don’t produce the crossing pattern needed for targeted joint relief.