Which heat modality is contraindicated in children due to the potential for premature growth plate closure?

• A. Microwave therapy
• B. Infrared therapy
• C. Ultrasound
• D. Cryotherapy

Answer: (C)

Open growth plates in children are especially sensitive to heat, and the energy from deep heating can reach the physes and alter their normal development. Ultrasound delivers heat to deeper tissues, including near the ends of long bones where the growth plates reside, so its thermal effects could potentially cause premature growth plate closure or other physeal injury. That potential risk makes ultrasound contraindicated in pediatric patients when the growth plates are still open or near active physes.

In comparison, infrared therapy tends to cause more superficial heating, and cryotherapy is cooling rather than heating, so neither carries the same specific concern for premature physeal closure. Microwave therapy also heats tissues but is used less commonly in this context; the primary pediatric consideration here remains the deep heating risk associated with ultrasound near growth plates.