To evaluate the therapeutic effect from ultrasound in the treatment of plantar heel pain by physiotherapists and podiatrists, and to quantify the placebo effect of this electrophysical agent.
Patients experiencing episodes of plantar heel pain were allocated randomly, at each episode, to receive either true ultrasound (machine calibrated to deliver a dose of ultrasound at 0.5 w/cm2, 3 MHz, pulsed 1:4), for eight minutes, or sham ultrasound (only the timer on the machine activated). Each episode was treated, according to randomisation, eight times. An independent observer set the equipment before obscuring the control panel with a drape. All treatments were undertaken by the same operator. Patients' pain scores were measured on a 10 cm linear analogue scale before the course of eight treatments commenced and at the end of the course, and analysed using a Wilcoxon Signed-Ranks test.
Nineteen patients experienced episodes of heel pain (seven bilateral). Both groups showed a reduction in pain; the improvement was 30% in the treated group and 25% in the placebo group (p = 0.5).
Therapeutic ultrasound at a dosage of 0.5 w/cm2, 3 MHz, pulsed 1:4, for eight minutes is no more effective than placebo in the treatment of plantar heel pain.