Effectiveness of low-intensity laser on pain in patients with supraspinatus tendinopathy: A triple-blind randomized controlled trial

BACKGROUND
Tendinopathy is an inflammatory process that occurs in and around the tendon when both are affected by a specific injury. The supraspinatus muscle is one of the
most common causes of shoulder pain.

AIM
To test the effectiveness of laser treatment in reducing pain, improving mobility, quality of life and pressure pain thresholds (PPT) in patients with supraspinatus tendinopathy.

METHODS
A randomised controlled clinical trial was conducted in which a physiotherapeutic intervention with a therapeutic
laser was performed for four weeks to observe the influence of supraspinatus tendinopathy in the shoulder on
pain. In addition, a triple-blind study was conducted, in which the physiotherapist performing the intervention
was blinded, as were the patients receiving the treatment and the person interpreting the study results. A sample of
80 patients was recruited and randomly divided into two groups: An experimental group and a control group.
Laser therapy was applied to the first group, and a placebo was applied to the second group.
RESULTS
Eighty participants were randomized to a therapeutic laser group (n = 40) or a placebo group (n = 40), with no
baseline differences in demographic or clinical variables. Post-intervention analyses revealed significantly greater
improvements in the laser group compared with placebo for pain intensity, muscle strength, and active shoulder
range of motion in flexion, extension, abduction, and external rotation (P < 0.05). No between-group differences
were observed for PPT, adduction, or internal rotation. Within-group analyses showed significant improvements in
all clinical variables only in the laser group. Repeated-measures the Analysis of Variance demonstrated a
significant time × group interaction for Disability of Arm, Shoulder, and Hand scores (P < 0.001), indicating
superior and sustained functional improvement in the laser group up to three months post-intervention.
CONCLUSION
The therapeutic laser therapy produced superior and sustained improvements in pain, strength, shoulder mobility,
and functional outcomes compared with placebo, supporting its effectiveness as an adjunct treatment