Do High-Volume Injections Affect the Ultrasonographic Neovascularization in Chronic Achilles Tendinopathy? A Randomized Placebo-Controlled Clinical Trial

Abstract

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.

What’s New in Orthopaedic Rehabilitation

“…High-volume injections have been used to treat midsubstance Achilles tendinopathy, with the theorized mechanism of action consisting of the disruption of neovascularization. In a double-blinded RCT, van Oosten et al found no reduction in Doppler blood flow in 62 subjects with chronic midsubstance Achilles tendinopathy following a high-volume injection (50 mL) compared with a placebo (2-mL injection) 16 . The amount of post-injection hypervascularity did not correlate with clinical outcomes, suggesting that the disruption of neovessels may not be a mechanism of action of high-volume injection used to treat midsubstance Achilles tendinopathy.…”

Staying in the Game: Interventions for Managing Achilles Tendinopathy in the In-Season Athlete

“…The reported outcomes following HVI for treatment of AT are mixed. Although several studies evaluating the effectiveness of HVI with or without steroids (3 case series and 2 RCTs) have found improvement in pain and/or function ranging from 3-wk to 1-year followup (29)(30)(31)(32)(33), other studies have found no superiority of HVI over placebo or correlation of clinical outcomes with change in Doppler flow (34,35).…”

Nearly half of patients with chronic tendinopathy may have a neuropathic pain component, with significant differences seen between different tendon sites: a prospective cohort of more than 300 patients

“…The presence of neovascularisation has been well established in various tendinopathies 14. Although several studies in recent years have identified that while this ingrowth of blood vessels may be common, its precise function remains unclear; and while hypotheses suggest these may be related to tendon hypoxia,48 their presence poorly correlates with symptoms49–51 and neovessels are not necessarily changed by treatments 52 53. In addition to these neovessels, tendinopathy samples have been shown to have higher levels of several neurochemicals directly associated with pain including glutamate, substance P and lactate 54–56.…”

“… 14 Although several studies in recent years have identified that while this ingrowth of blood vessels may be common, its precise function remains unclear; and while hypotheses suggest these may be related to tendon hypoxia, 48 their presence poorly correlates with symptoms 49–51 and neovessels are not necessarily changed by treatments. 52 53 In addition to these neovessels, tendinopathy samples have been shown to have higher levels of several neurochemicals directly associated with pain including glutamate, substance P and lactate. 54–56 The significance of these neurotransmitters remains unclear, but in addition to promoting angiogenesis, these may be triggering a ‘neuropathic-type’ pain by stimulation of the local nerve endings, as it is thought that the development of neovascularity may also be associated with the ingrowth of abnormal sensory nerve endings into tendinopathic tendons.…”