Effects of Extracorporeal Shock Wave Therapy, Photobiomodulation, Ultrasound, and Electrotherapy Modalities on Rotator Cuff Related Shoulder Pain: A Systematic Review

Background/Objectives: The term rotator cuff related shoulder pain (RCRSP) refers to pain localized in the deltoid region. RCRSP and the associated pain and functional limitations have a significant impact on the quality of life of those affected. This systematic review aimed to investigate the treatment and follow-up effects of extracorporeal shockwave therapy (ESWT), photobiomodulation (PBM), ultrasound (US), and electrotherapy modalities (ET) in RCRSP. Methods: A comprehensive literature search was conducted. In addition, the reference lists of the included studies and relevant reviews were screened to identify further eligible studies (snowballing). Randomized controlled trials (RCTs) investigating the treatment and follow-up effects of ESWT, PBM, US, and ET for RCRSP, with control groups receiving sham or alternative physiotherapeutic treatments, were included without restrictions on date or language. Two reviewers independently conducted the literature screening, data extraction, and risk-of-bias assessment for the included studies. The differences in pain between pre- and post-intervention, the between-group differences (intervention vs. control), as well as subgroups (low-level laser therapy [LLLT] and high power laser therapy [HPLT]) were analyzed. Results: A total of 20 RCTs with 1152 patients were included. Quality assessment indicated low risk of bias in 55% of the included studies, some concerns in 35%, and high risk in 10%. In the nature of a sustainable therapy, therapeutic modalities were mostly not applied in isolation but rather in combination with conventional physiotherapeutic interventions. One study showed an end-of-treatment pain reduction for ESWT, and one study showed no follow-up effect on pain. PBM showed an end-of-treatment effect and follow-up effect. The subgroup analysis suggested that only HPLT demonstrated a clear end-of-treatment effect. Due to the limited number of studies, no subgroup analysis could be performed for follow-up outcomes. US showed beneficial effects both at the end of treatment and at follow-up, while ET demonstrated an end-of-treatment effect. Further studies are needed for the follow-up effect. Conclusions: HPLT, US, and ET showed consistent additive treatment effects, while PBM and US showed follow-up effects. In general, especially for PBM, ESWT, and ET, more studies are needed to gain a broader insight into this topic.