Objective: High-volume injections (HVIs) are thought to target neovascularization in chronic midportion Achilles tendinopathy (AT), yet the mechanism has not been clarified. Therefore, we aim to evaluate whether a HVI decreases ultrasonographic Doppler flow in patients with chronic midportion AT.
Design: A double-blind, randomized, placebo-controlled clinical trial.
Setting: Sports medicine department at a district general hospital.
Patients: Sixty-two patients with clinically diagnosed chronic midportion AT were included and randomized into the intervention group (HVI-group, n = 30) and placebo group (n = 32).
Intervention: A daily calf-muscle exercise program combined with either (1) a HVI (HVI-group: 50 mL) or (2) a placebo-injection (placebo-group: 2 mL) with a mixture of saline and lidocaine.
Main outcome measures: Primary outcome was the surface area quantification (SAQ) score (%) of the Doppler flow during a 24-week follow-up period. Secondary outcome was the association between SAQ scores and symptoms [Victorian Institute of Sports Assessment-Achilles (VISA-A)]. Outcomes were measured before, directly after, and 1 hour after the injection and at 2, 6, 12, and 24 weeks of follow-up.
Results: There was no significant between-group difference at 24 weeks [-0.1%; 95% confidence interval (CI), -4.9 to 4.7] or at any of the other time points. Change in SAQ score did not correlate with the change in VISA-A score (P = 0.93).
Conclusion: A HVI does not affect Doppler flow in patients with chronic midportion AT. Also, changes in Doppler flow were not associated with the clinical outcome. These findings challenge the theoretical basis of a HVI.
Trial registration: NCT02996409.
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