Our aim was to evaluate the efficacy of polydeoxynucleotide (PDRN) injections compared to standardized prolotherapy for patients with lateral epicondylitis (LE).

In this randomized, double-blind, active-controlled trial, eligible patients with LE received intra-tendinous injections (1mL of PDRN or hypertonic dextrose [15%]) under ultrasound (US) guidance at weeks 0, 2 and 4. Primary outcome was Visual Analogue Scale (VAS) for elbow pain. Secondary outcomes were pain-free grip strength (PFGS), pressure-pain threshold (PPT), isokinetic wrist extensor strength (IWES), patient-rated tennis elbow evaluation (PRTEE), EQ-5D-5L and US characteristics of the LE. All outcomes and adverse events were assessed at weeks 0, 6 and 12.

The final analysis included 38 patients (PDRN injection, n=19; prolotherapy, n=19) (Fig. 1) (Table 1). Significant improvements from baseline to 12 weeks were observed in VAS for elbow pain in both groups (53.6±19.1mm, P<0.001 in PDRN; 50.6±16.8mm, P<0.001 in prolotherapy) (Fig. 2). While the between-group difference in VAS was not significant (P=0.605). Significant pre-versus-post improvements were observed within each group for the secondary outcomes other than US characteristics (P<0.001, P=0.001, and 0.003, respectively). Of these outcomes, PFGS, PPT, and IWES exhibited increase of up to 90% (ratio=affected side/unaffected side×100) in both groups. However, all secondary outcomes showed non-significant between-group differences. There were no serious adverse events that resulted in drop-outs.

PDRN injections and prolotherapy used as standardized interventions can be safe and effective treatments improving for LE-related pain and function.