Additionally, emerging evidence indicated that most overuse injuries to runners, like Achilles tendonitis and plantar fasciitis , aren’t inflammatory problems at all—calling into question the value of applying an anti-inflammatory corticosteroid. But there is another way of delivering corticosteroids and other drugs to injured areas which merits an examination, and that’s a process called iontophoresis.
What is Iontophoresis
Instead of using a needle to deliver medication, as is the case with an injection, iontophoresis uses an electrical current: pad-like electrodes are attached to your skin, and an electrical potential is applied, creating a small current that runs through your body from one electrode to the other. The electrons that flow along this current can also “drag” charged chemicals through your skin when the proper solution is applied to the electrode. This allows some medications, like corticosteroids, to be transported to the location of an injury without using a needle.
This is significant because there is some research, albeit in animals, that indicates that the damage to tendons associated with corticosteroid injections may be from the needle, not just the medication.
Iontophoresis treatment effectiveness
David Martin and others at Wake Forest University used rabbits to compare the effects of injections and iontophoresis on tendons. Three groups of rabbits were treated in the study. The first received a corticosteroid injection into the Achilles tendon, the second received an injection of saline solution (salt water) into the tendon, and the third received iontophoresis of the same corticosteroid.
While both groups that got injections suffered damage to the tendon, the rabbits which were administered corticosteroids via iontophoresis did not.
Given the results of Martin et al., the next question we should examine is how effective iontophoresis is in treating running injuries. There are some reports on using iontophoresis to treat overuse injuries that seem to show some promise.
Iontophoresis is best suited for injured areas which are very near to the skin—tissue deep inside the body is too far for the electrically-transported chemicals to effectively penetrate.
For this reason, most studies have looked at injuries near the skin, like Achilles tendonitis or plantar fasciitis.
A 2003 study from Sahlgrenska University in Sweden examined using iontophoresis of dexamethasone, a common corticosteroid to treat “acute” Achilles tendonitis, which had been present for under three months. Fourteen subjects were treated with iontophoretically-delivered dexamethasone over a two week period, while a control group of eleven received iontophoresis of saline solution.
Throughout the treatment period, both groups received standard physical therapy in addition to their iontophoresis treatments. At the conclusion of the study, range of motion, pain during physical activity, and tendon swelling were all decreased in the experimental group compared to the control group.
A similar study published by Scott Gudeman and others in 1997 investigated the use of dexamethasone iontophoresis in a group of patients with plantar fasciitis. Thirty-nine patients with plantar fasciitis were split into an experimental and control group. Like Neeter et al., both groups received either real or “sham” iontophoresis over a two-week period totaling six treatments in Gudeman et al. Both groups also followed a standard rehab protocol of stretches and exercises during and after the treatment.
Interestingly, though the experimental group showed more rapid improvement in symptoms, the control group had caught up by one month after the treatment was completed. Gudeman et al. interpreted this to mean that the iontophoresis of dexamethasone helped accelerate recovery, but should not be viewed as a replacement for a traditional recovery program. Gudeman et al. suggest that iontophoresis could be used by active patients like athletes to speed their recovery from plantar fasciitis in conjunction with a normal rehab program.
Despite these initial successes, there are still some big unanswered questions. Will the benefits of iontophoresis hold up when tested in well-designed, large-scale clinical trials? And if they do, how does the iontophoretically-delivered medication such as dexamethasone reduce pain or encourage recovery?
Most anti-inflammation treatments have not held up to scientific scrutiny, seeing as most running injuries do not seem to be inflammatory in nature. As previous articles here on RunnersConnect have discussed, there’s no evidence NSAIDs like Advil and Aleve help your recovery from injuries. Corticosteroids have a checkered scientific record, too. Further, the possible side effects—gastrointestinal problems and stomach ulcers with NSAIDs, possible tendon ruptures with injected corticosteroids—are another reason to question their use.
While iontophoresis does not appear to have the big drawbacks associated with NSAIDs and injected corticosteroids, it’s still a relatively new treatment without a whole lot of scientific backing. Minor side effects, like redness and skin irritation, have been reported but there are still no studies on long-term effects.
Ultimately, iontophoresis is probably best thought of as a potentially useful adjunct to a traditional recovery program.
The basic science behind it suggests that it would be best at treating overuse injuries near the skin, like Achilles tendonitis and plantar fasciitis. Other tendons very near the skin, like the patellar tendon and some of the smaller tendons in the feet, are also potential candidates for iontophoresis.
If you think you might benefit from iontophoresis, you should talk to your doctor or podiatrist. Since corticosteroids are prescription medications, you can’t get them straight from a physical therapist or athletic trainer. Though there’s no guarantee of success with iontophoresis, there is some encouraging evidence that it can speed recovery and get you back running sooner.
1. Hugate, R.; Pennypacker, J.; Saunders, M.; Juliano, P., The Effects of Intratendinous and Retrocalcaneal Intrabursal Injections of Corticosteroid on the Biomechanical Properties of Rabbit Achilles Tendons. Journal of Bone and Joint Surgery 2004,86 (4), 794-801.
2. Kleinman, M.; Gross, A. E., Achilles Tendon Rupture following Steroid Injection. The Journal of Bone & Joint Surgery 1983,65-A (9), 1345-1347.
3. Costello, C. T.; Jeske, A. H., Iontophoresis: Applications in transdermal medication delivery. Physical Therapy 1995,75, 554-563.
4. Martin, D. F.; Carlson, C. S.; Berry, J.; Reboussin, B. A.; Gordon, E. S.; Smith, B. P., Effect of injected versus iontophoretic corticosteroid on the rabbit tendon. Southern Medical Journal 1999,92 (6), 600-608.
5. Neeter, C.; Thomeé, R.; Silbernagel, K.; Thomeé, P.; Karlsson, J., Iontophoresis with or without dexamethazone in the treatment of acute Achilles tendon pain. Scandanavian Journal of Medicine & Science in Sports 2003,13 (6), 376-382.
6. Gudeman, S. D.; Eisele, S. A.; Heidt, R. S. J.; Colosimo, A. J.; Stroupe, A. L., Treatment of Plantar Fasciitis by lontophoresis of 0.4% Dexamethasone. A Randomized, Double-Blind, Placebo-Controlled Study. American Journal of Sports Medicine 1997,25 (3), 312-316.