Therapeutic ultrasound has been used for decades in the rehab of a multitude of injuries and conditions, but does it actually do what it is claimed to do? Lets get into it. Therapeutic ultrasound is different from diagnostic ultrasound. Diagnostic (think looking at babies) uses a transducer to send sound waves into tissue and a computer/device uses those sound waves to generate an image. These are unbelievably useful for looking at organs, growing babies, tumors, tissues, etc. Therapeutic ultrasound also has a number of uses. We will focus strictly on that being used in the physical therapy space. A low frequency sound wave is used to enter the tissue being treated with the goal of warming it up, or bringing blood flow to the area, or healing the tendon or bone. This type of ultrasound has been around since the 50’s and has been a staple of mainstream physical therapy. Almost everyone that has gone to physical therapy has likely at some point experienced the warm or cold gel on them and the wave of a metal tipped transducer. Does this ultrasound really do what it claims? Is there any evidence to support its use?
Therapeutic ultrasound mechanism of action is to basically vibrate the tissues. Through this vibration it heats up with tissues (think rubbing your hands together to make heat). This heat, while can be beneficial to the tissues doesn’t really have much of a healing effect. There are essentially no well performed studies that support ultrasound use for healing or aiding in recovery. The warming of the tissue can cause increased tissue extensibility however this is only superior to doing nothing before attempting to stretch the tissue. An active warm up is more superior for blood flow and warming body/tissue temperature as well as getting the body ready to move. Numerous studies do support that ultrasound warms the tissue temperature however they do not lead to functional or mobility gains like an active warm up will.
Now if you have been in my clinic, you will see an ultrasound machine. So what gives right?! Well there are two reasons for this. Firstly ultrasound has some evidence for ruling in/out stress fractures. Performing an ultrasound over a suspected area of stress fracture can be uncomfortable and give more information that would allow me to refer someone to the appropriate doctor to obtain more imaging. The second….combo units were on sale when I bought them.
Want to discuss more about ultrasound. Give us a ring or drop an email, we’d be happy to have a chat about ultrasounds.
