Since manual palpation is a subjective procedure for identifying and differentiate Myofascial Trigger Points -MTrPs-, the use of Shear Wave Elastography -SWE- as an objective alternative is increasing. This study aimed to analyze pain pressure thresholds -PPTs- and SWE differences between active MTrPs, latent MTrPs and control points located in the upper trapezius to analyze the association of SWE features with clinical severity indicators (e.g., pain extension area, PPTs, neck pain and neck disability). An observational study was conducted to calculate the correlation and to analyze the differences of sociodemographic, clinical and SWE features on 34 asymptomatic subjects with latent MTrPs and 19 patients with neck pain and active MTrPs. Significant PPT differences between active with latent MTrPs (p < 0.001) and control points (p < 0.001) were found, but no differences between latent MTrPs and control points (p > 0.05). No stiffness differences were found between active MTrPs with latent MTrPs or control points (p > 0.05). However, significant control point stiffness differences between-samples were found (p < 0.05). SWE showed no significant correlation with clinical severity indicators (p > 0.05). No stiffness differences between active and latent MTrPs were found. Neck pain patients showed increased control point stiffness compared with asymptomatic subjects. SWE showed no association with clinical severity indicators.
Keywords: elasticity imaging techniques; myofascial pain syndromes; neck pain; trigger points.