What should you know about TENS units and knee swelling?

Knee swelling can reflect irritation, injury, inflammation, or fluid collecting around the joint. It may occur with an ACL Tear, Baker's Cyst, Gout, Knee Bursitis, Knee Osteoarthritis, or Meniscus Tear. Each condition has different examination findings and treatment needs; the swelling itself does not identify one cause.

TENS sends a tingling through skin pads and may alter pain processing. It cannot drain fluid, heal a torn structure, or treat infection. A clinician may need to assess warmth, range of motion, stability, injury history, and whether the swelling is inside or around the joint.

Rest from activities that clearly increase swelling, elevate the leg when comfortable, and use gentle movement within a pain-free range. If a clinician has approved TENS, follow the device instructions, place pads on clean intact skin around the painful area, and keep them away from broken skin or areas with reduced sensation. Stop for burning, rash, dizziness, or increased pain.

Do not use TENS to postpone assessment, and do not apply it while sleeping, bathing, driving, or operating machinery. A physiotherapist can guide loading and movement after the cause has been considered. If fluid needs removal, Joint Aspiration is a clinician-delivered procedure, not a home-device function.

Seek urgent medical care if the knee is hot and red with fever, you cannot bear weight, the joint is locked, swelling followed a major injury, or the calf becomes painful and swollen. Sudden breathlessness or chest pain needs emergency help. Prompt review is also appropriate when swelling repeatedly returns or ordinary movement is becoming harder.

Ask what may be causing the swelling, whether you need imaging or fluid assessment, which activities to pause, and whether TENS is suitable for your skin and sensation. Clarify when to begin strengthening and which changes in heat, redness, locking, or weight-bearing should trigger urgent review.