What is a Bone Growth Stimulator? How Do They Work?
Bone growth stimulators are an emerging technology that helps bone breaks heal faster. They're often used after spinal fusion surgery or when a break won't join. But how do they work?
Before reading, please note that Shop-Orthopedics does not sell bone growth stimulators. They must be prescribed by a doctor and are typically covered through insurance.
Bone growth stimulators are being prescribed more often in our society to help heal stubborn fractures. Every year, around 10% of the 8 million people who experience some sort of bone break (either accidental or medically induced) have trouble healing correctly. This is referred to in the medical world as a 'non-union' or 'delayed union'. When a bone doesn't heal properly, mobility and quality of life are greatly reduced. Thus the bone growth stimulators come into play to help bones heal faster.
Bone growth stimulators come in different packages, but all do the same thing. Generally they are external and are placed at the site of fracture. The power button is pressed and the machine goes to work. It's not a mechanical stimulation, however. Bone growth stimulators are based on either sound frequencies or electricity (typically electrical bone growth stimulators are internal). Most bone growth stimulators are limited so that a patient can't overdo the therapy. They are often locked by an internal clock that prevents the device from activating for more than 30 minutes twice daily, and most will completely stop working after 9 months, or 270 days (rendering it useless).
Bone Growth Stimulators from DonJoy
How does a bone growth stimulator actually work? The details are a little fuzzy according to various medical journals and studies. Doctors do see the results, however, and insurance companies will often provide for a bone growth stimulator. The information below has been compiled from various sources and gives the best explanation to why a bone growth stimulator works to heal bones.
In 1953, a study was conducted by a doctor named Iwao Yasuda. Dr. Yasuda applied electrical current to the femur of a rabbit for 3 weeks. At the end of the three weeks, Dr. Yasuda noticed something interesting - new bone growth appeared at the site of the cathode. This was a major development for bone growth stimulators, and it opened the pathway to other investigations in bone growth stimulation. Including sound
Dr Iwao Yasuda
In the 1940s, submarines were accidentally killing fish with their ultrasound sonar systems. The super high intensity of the waves were heating up and killing any aquatic life unfortunate enough to come into contact with them. This sparked the idea that ultrasound could help manage pain. Heat therapy works great for pain relief, and ultrasound waves can penetrate and heat deeper than traditional things like heat packs. Ultrasound therapy typically operates at high frequencies (2-3 watts/square centimeter).
One side effect of ultrasound therapy that was discovered sometime in the 1980s is that at lower frequencies, ultrasound can induce osteogenesis (bone growth). Again, rabbits were the test subjects. Dr. L.R. Duarte drilled holes in the femurs of 23 rabbits (bilateral - both the left and right femurs had holes). For 15 minutes a day, he exposed one of those holes to low-intensity, pulsed ultrasound. At the end of his experiment he found that the holes treated with ultrasound healed better and faster than those that were left to heal naturally.
In 1987, Dr. Duarte presented his findings. 7 years later, in 1994, the FDA approved marketing for ultrasounds that could heal fresh fractures.
The method of action for bone growth stimulators is not quite clear, but the consensus is that ultrasound stimulates production of proteins and chemicals in the body that help bones heal. The production of IGF-2 (a protein that helps bones heal) is notably higher when using a bone growth stimulator. While using ultrasound stimulators, many other natural healing mechanisms in the body seem to be increased as well, including PTH, insulin, IL-2, transferrin, LDL, and more
By applying a bone growth stimulator to the site of fracture, healing is stimulated and accelerated. This is proved by various studies on the subject. Check out the video below for a visual breakdown of the science.
If you break your arm or hurt yourself in any way, you should be contacting your doctor. Bone growth stimulators aren't completely understood and appear to be relatively risk free, but, as with any medical device, you should take caution to use it correctly so as not to accidentally injure or hurt yourself. If your injury is not a fracture, but rather a bruise or sprain, you should consider one of our custom CTi knee braces, a back brace, or our pain relief creams for your symptoms.
The classic: Fundamental aspects of fracture treatment by Iwao Yasuda, reprinted from J. Kyoto Med. Soc., 4:395-406, 1953. Clin Orthop Relat Res. 1977 May; (124):5-8.
The stimulation of bone growth by ultrasound. Duarte LR Arch Orthop Trauma Surg. 1983; 101(3):153-9.