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

The efficacy of the relatively new wireless iontophoresis patch compared with the traditional wired dose controller is unknown.

To determine the differences among 2 iontophoresis drug-delivery systems (wireless patch versus wired dose controller) and a sham treatment in treating patellar tendinopathy.

Randomized controlled clinical trial.

Physical therapy clinic.

Thirty-one participants diagnosed with patellar tendinopathy (men = 22, women = 9, age = 24.5 ± 5.9 years).

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.

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.

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).

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.