Ultrasound (US) and low-level laser therapy (LLLT) are frequently used for myofascial trigger points (MTP) even though there is a lack of evidence for usage as stand-alone treatments. The aim of the study was to determine, on MTP of the upper trapezius muscle (uTM), the effects of US and LLLT per se, as administered in accordance with the procedures reported by surveys about their usage among physiotherapists. Design was set as a double-blind, randomized, placebo-controlled study. Sixty participants with one or more active MTP in uTM (28 women and 32 men; mean age 24.5 ± 1.44 years) were recruited and placed at random into one out of five groups: active US (n = 12), placebo US (n = 12), active LLLT (n = 11), placebo LLLT (n = 11) and no therapy (control, n = 14). The participants and outcome assessor were blinded to the group assignment and therapy delivered. Three outcome measures were assessed at baseline, after a 2-week treatment and 12 weeks after the end of the intervention (follow-up): pressure pain threshold, subjective pain on a numerical rating scale and muscle extensibility performing a cervical lateral flexion. All subjects assigned to the intervention groups were treated five times weekly for overall 10 treatments given. Two-way ANOVA was used to compare differences before and after intervention and among groups at each time-point. Following the 2-week intervention, all groups showed pressure pain threshold, numerical rating scale and cervical lateral flexion significant improvements (p < 0.05), which were confirmed at the follow-up. When performing multiple comparisons, controls scored significantly less than both the active therapies and placebos, whereas no differences were observed between active therapies and placebos.
The study found ultrasound and LLLT to provide significant improvements in pain and muscle extensibility, which were superior to no therapy but not to placebos, thus raising concerns about the suitability, both economically and ethically, of administering such common physical modalities as stand-alone treatments in active MTP of the uTM.