Objective: To assess the efficacy of lidocaine iontophoresis on myofascial
trigger-point pain. Setting: University athletic training facility. Design:
Randomized, double-blind, placebo-controlled, repeated-measures. Subjects:
Twenty-three subjects with sensitive trigger points over the trapezius. In
tervention: Placebo iontophoresis treatment without current or lidocaine, c
ontrol treatment using distilled water and normal current dose, medicated t
reatment using 1 % lidocaine and normal current dose. Main Outcome Measure:
Trigger-point pressure threshold assessed with an algometer. Results. ANOV
A revealed a significant difference among treatments (F (2,40) = 7.38, P <
.01). Post hoc comparisons revealed a significant difference in pressure th
reshold between the lidocaine treatment and the control (P =.01) and placeb
o (P =.001) treatments. Effect sizes of .28 and .39, respectively, were fou
nd for these comparisons. Conclusions: Although the data revealed significa
nt differences between treatments, the small effect sizes and magnitude of
the pressure-sensitivity deviation scores suggest that iontophoresis with 1
% lidocaine is ineffective in treating trigger points.