Clinical benefits and safety of polynucleotides injections for the treatment of tendinopathies: A multicenter, single-cohort, retrospective study

: Background: Tendons are among the most frequently affected structures in musculoskeletal disorders. Polynucleotides (PNs) have been proposed to promote tendon regeneration by enhancing collagen synthesis and reducing inflammation. This retrospective clinical study aimed to evaluate the clinical effects of PNs injections in patients with different kinds of tendinopathy (mostly gluteal tendinopathy, biceps brachii tendinopathy and Achilles tendinopathy), focusing on pain reduction and functional improvement. Methods: Sixty-eight patients with clinically diagnosed tendinopathy received three peritendinous injections of a PNs-based medical device at baseline (T0), two weeks (follow-up 1), and four weeks (follow-up 2) post-T0. Follow-up assessments were conducted at follow-up 1, follow-up 2-, eight- and 24-weeks post-follow-up 2. The primary outcome was pain reduction measured by the numerical rating scale (NRS). Secondary outcomes included pain-related functional limitation (VAS-function), the Clinical Global Impression-Improvement scale, and patient satisfaction on a 5-point Likert scale. Results: A mean NRS and VAS-function reduction of, respectively, -1.76 ± 0.08 and -1.74 ± 0.07 were found per follow-up, with statistically significant improvements over time. At the final follow-up, 88% of patients reported being "satisfied" or "very satisfied" with the treatment. Conclusions: The results support the efficacy and safety of PNs treatment in patients with tendinopathies, as it led to significant improvements in pain and function. Further high-quality clinical studies are needed to validate these findings.