Fractures typically heal by themselves if they are simple, non-compound fractures with proper immobilization. However, compound fractures with multiple broken pieces and dislocation may require open reduction with internal fixation. Children have amazing healing capacities with regards to bone fracture but as people age, bone repair becomes a more prolonged process that may take months to heal despite fixation. This can lead to months of disability and even when the fracture has healed, it may result in some limitations in mobility.
An Ultrasound Emitting Scaffold That Shortens Fracture Healing Time
University of Connecticut bioengineers have recently come up with a special device that can accelerate the healing process of bone fractures even in the elderly. This device not only provides a support structure for the broken bones to heal around, but it also stimulates the bone electrically urging it to heal at a more rapid rate than normal.
Their device is based on the concept that the application of a small electrical field around the location of the fractured bone may be able to replicate the body’s own natural electrical field to aid in faster regeneration of the osteocytes. Although this is not a new concept, the practical application of this concept was not possible until now as the devices which can emit such electrical fields are large, toxic, and require numerous wires to charge them. Placing these large devices demanded an invasive surgical procedure that would make these devices inconvenient and not worthy of all the effort.
But with the development of a scaffold-like device made up of a polymer without any toxicity by engineers from Uconn the concept of using a stimulated electrical field to accelerate bone fracture healing may soon become a medically feasible technique. Their device has the capacity of generating a regulated level of electrical field that can stimulate bone growth. This device is particularly useful in large fractures that heal slowly with complications.
Scientists have previously experimented with the idea of using scaffolds to fix large fractures, but the concept of combining a scaffold with an electrical field emitting device is a novel idea. Using mice models with fractures of the skull, the engineers employed scaffolds with ultrasounds controlled by a remote that generated a few millivolts of electrical voltage to stimulate bone growth. The scaffold causes vibration via ultrasound which in turn forms an electrical field around the site of the fractured bone.
How does the device work?
A non-toxic polymer scaffold is implanted at the site of the bone fracture. The patient will use an ultrasound wand and wave it over the fractured bone by themselves. It doesn’t require any assistance and is free from the hassles of changing batteries or connecting wires. Once the fractured bone has healed, no surgery is required to remove the scaffold as the device being non-toxic can be left inside the healed bone without risk for adverse effects.
The device still requires extensive research and clinical trials before it becomes available for the general population. Meanwhile, the UConn bioengineers are attempting to refine the polymer further while simultaneously trying to understand the mechanism behind the rapid healing observed under induced electrical fields.
“Once we understand the mechanism, we can devise a better way to improve the material and the whole approach of tissue stimulation,” says Uconn biomedical engineer Thanh Nguyen.