Wireless Versus Wired Iontophoresis for Treating Patellar Tendinopathy: A Randomized Clinical Trial

Abstract

Context The efficacy of the relatively new wireless iontophoresis patch compared with the traditional wired dose controller is unknown. Objective To determine the differences among 2 iontophoresis drug-delivery systems (wireless patch versus wired dose controller) and a sham treatment in treating patellar tendinopathy. Design Randomized controlled clinical trial. Setting Physical therapy clinic. Patients or Other Participants Thirty-one participants diagnosed with patellar tendinopathy (men = 22, women = 9, age = 24.5 ± 5.9 years). Intervention(s) Participants were randomly assigned into 1 of 3 treatment groups: wireless patch, wired dose controller, or sham treatment. Participants in the active treatment groups received six 80 mA/min iontophoresis treatments using 2 mL of 4% dexamethasone sodium phosphate. During each visit, clinical outcome measures were assessed and then the assigned treatment was applied. Main Outcome Measure(s) Clinical outcome measures were Kujala Anterior Knee Pain Scale, pressure sensitivity, knee-extension force, and sit-to-stand pain assessment using a numeric rating scale. For each clinical outcome measure, we used a repeated-measures analysis of covariance to determine differences among the treatment groups over the treatment period. Results Participants reported a clinically important improvement on the Kujala Anterior Knee Pain Scale across all treatment groups, with no differences among groups (P = .571). A placebo effect was observed with pressure sensitivity (P = .0152); however, the active treatment decreased participants' pain during the sit-to-stand test (P = .042). Conclusions A placebo effect occurred with the sham treatment group. Generally, improvement was noted in all groups regardless of treatment type, but greater pain reduction during a functional task was evident within the active treatment groups during the sit-to-stand test. The wireless patch and wired dose controller treatments were equivalent across all variables.