Using TENS to Facilitate Delayed Union in Fractures
By Sandra Abramson. PT
The patient with a nonunited fracture poses a challenge for clinician. Management is of the complicated and time consuming. The options for physicians have been limited to letting the fracture continue to heal slowly on its own, intervening with bone grafts or internal fixation, or in newer developments, introducing natural or synthetic substances that enhance osteogenesis, including growth factors.
As physical therapists, our involvement has been primarily one of waiting until healing has occurred and then proceeding with rehabilitation.
In the past few years, however transcutaneous electrical nerve stimulation, a modality that has been used for treating pain with varying degrees of success, has provided therapists with an opportunity to help heal these recalcitrant fractures.
In the following case study, TENS was used to test its effectiveness as a modality for fracture healing in an ankle fracture after 10 months of healing. The study indicates that TENS may be efficacious in healing the fracture site, even after months of delay.
This study concerned a 42-year-old woman who had sustained a severely displaced bimalleolar fracture of her right ankle. She underwent open reduction and internal fixation with cortical screws to the fracture fragments of the medial malleolus and a tubular plate for fixation of the lateral fragments She wore a cast for six weeks, after which time she advanced from crutches to cane to independent ambulation.
She exercised and practiced proper gait patterns.
IN TAKING the patients history, she reported that she had undergone radiation treatment for malignant melanoma on the right flank two months prior to her injury and for six months following. We also discovered that her diet was deficient in calcium and iron.
The TENS study was undertaken after routine X-ray films revealed that healing was not complete. It was past the six-month mark usually attributed to delayed union. As complete healing was a condition for removal of hardware ideally accomplished by one year post-injury, a solution was sought for alternative forms of healing. After reading an article in the June 6 1994. edition of ADVANCE on the uses of TENS for bone healing, setup parameters were sought and permission granted from her orthopedist for a trial of five to six weeks of therapy using TENS for fracture healing.
An absence of fracture lines would signal successful healing and the ability to go ahead with removal of hard-wart.
A dual-function TENS device was utilized for the treatment. As per Joseph Kahn PhD. PT. a physical therapist who had used TENS for fracture healing with success, transmission gel was spread on each transcutaneous carbon electrode and secured behind each malleolus. The machine was set on maximum rate and pulse width (setting 10) and the intensity turned up to barest perceptible sensation (setting 1-2). The patient was instructed to turn on the machine for one hour, four times dally. She was shown how to operate the device and was given the equipment for use at home. She applied the TENS for five weeks according to these instructions.
TO MAXIMIZE her healing, she was advised to improve her nutrition. She was placed on a diet rich in vita-nuns and minerals, taking high potency calcium supplements of 500 mg and Theragran-M vitamins. Her meals included such calcium-rich foods as yogurt and cheese. Even though a formal nutritional work-up was not done, (and not technically part of the study), the patient enjoyed her new diet and stated she felt more energized.
The results were dramatic. Six weeks after the start of TENS treatment, follow-up radiographs showed an absence of fracture lines at both medial and lateral fracture sites.
The patient did not have any side effects such as skin sensitivity nor irritation from the treatment. The orthopedist pronounced the fracture completely healed and plans were made for removal of the plates and screws.
Delayed healing following a fracture can occur for many reasons. Local factors such as infection following open fracture, interruption or blood supply, or poor contact between bone ends may predispose a fracture to nonunion. Systemic factors can also affect the formation of callus or bridging crucial for osteogenisis of the bone. Poor nutrition, radIation therapy. iron-deficiency anemia, and age have been proven to affect the time and quality of healing.
A diet deficient in calcium and iron. as well as protein can influence the body’s ability to heal after injury. These nutrients are involved in promoting formation of new tissue. Therefore, nutrition is vital, especially in the setting of immune compromise.
IT IS NOT KNOWN precisely how TENS or other form, of electrical stimulation enhances osteogenesis. It may be the bone itself or the electrical energy generated that makes the difference. It is known that bone goes through various stages of regrowth after injury. One of the early stages requires an "inductor" to help the process of bridging the gap between bone ends. It may well require electrical stimuli for this induction.
It is also known that bone has piezoelectrical qualities, not unlike those of natural crystals, and that currents are generated when bone is stressed even at very low microamperage. Microampere stimulation, since it has no effect on sensory or motor circuits, is believed to stimulate circulation of ions and radicals in the capillaries. This facilitates the transport of necessary nutritional material to the key area and enhances tissue and wound repair. It follows, therefore, that the bones need the additional blood supply, containing oxygen and other nutrients, for complete healing following a severe fracture and altered immune system.
More clinical trials with controlled studies should be done to document scientific proof that TENS and diet are responsible for healing a nonunited fracture. However, based on this and similar studies, physicians and PTs can safely apply TENS for routine use in delayed fracture healing.
Reference list available upon request
· About the author: Sandra Abramson is a physical therapist in private practice in New York City.
· The author thanks Dr. Kahn. clinical assistant professor, department of physical therapy, State University of New York. and Dr. Michael Aleziedes adjunct orthopedic attending physician at Lenax Hill Hospital. New York. for their assistance with the study.