Ultrasound-guided 5% dextrose perineural therapy at the axillary nerve for the treatment of shoulder pain in patients with rotator cuff tendinopathy: a randomized, double-blind, sham-controlled trial.

Background: 5% dextrose perineural injection therapy (PIT) is a low-cost, accessible, and non-toxic pain relief treatment. No study examined the effects of PIT using a 5% dextrose solution for axillary nerve-related shoulder pain. Objectives: We aimed to investigate the effects of 5% dextrose PIT in the proximal part of the axillary nerve (pAxN) and distal part of the axillary nerve (dAxN) compared to a sham injection, combined with self-exercise in patients with rotator cuff tendinopathy. Methods: This randomized controlled trial included 40 patients with moderate to severe pain from rotator cuff tendinopathy. Participants were randomly assigned to one of 3 groups: 5% dextrose PIT in pAxN, dAxN, or a sham injection. All groups performed self-exercise at home. Pain was measured using the visual analog scale (VAS), and secondary outcomes included the oxford shoulder score (OSS) and range of motion (ROM). Blinding was maintained for participants and assessors. Results: After excluding one participant, 39 individuals (13 per group) were included in the analysis. The dAxN group showed significant pain reduction at 2 and 4-weeks, with estimated mean VAS reductions of -2.46 (-3.87, -1.05) and -1.49 (-2.89, -0.08), respectively, compared to the sham group. However, the pAxN group did not demonstrate a significant difference in pain reduction compared to the sham group. There were no significant differences between groups in other outcomes. Conclusions: Combining 5% dextrose PIT at the dAxN region with self-exercise led to superior short-term pain reduction in patients with rotator cuff tendinopathy. Nonetheless, further large-scale clinical trials are necessary to validate these findings.