Efficacy of diadynamic currents in the treatment of musculoskeletal pain: a systematic review

Introduction
Musculoskeletal pain (MSP) is one of the main causes of chronic pain in adults and the main reason for disability. Diadynamic currents (DDC) are described as classic electrotherapy modalities for MSP management, however, the available information and studies that support their use are limited. To describe the efficacy of DDC in the treatment of MSP.

Methods
Randomized clinical trials (RCTs) were identified in PubMed, Scopus, Web of Science, Cinahl, and Science Direct databases dated August 1, 2021. Three independent investigators reviewed articles titles and abstracts to determine their eligibility, risk of bias and quality using the Cochrane Rob2 tool and the PEDro scale. Pain reduction was considered as the main outcome and changes in range of motion, strength, or disability/functionality as secondary outcomes.

Results
13 RCTs were obtained after eliminating duplicates, reviewing titles, abstracts and applying the selection criteria. The MSP conditions included joint (n = 9) and soft tissue disorders (n = 5). The studies had a low risk of bias and good quality with average scores of 7 for the PEDro scale. A pain reduction was observed for DDC treatments, as well as an improvement in functionality in favor of experimental groups (p < 0.05).

Conclusions
DDC are effective in reducing MSP and improving functionality compared to other electrotherapy modalities. This review made it possible to generate dosage recommendations and establish that the best therapeutic results are achieved with combined diadynamic applications.