Topical Glyceryl Trinitrate (GTN) and Eccentric Exercises in the Treatment of Midportion Achilles Tendinopathy (the NEAT trial): a Randomised Double-Blind Placebo-Controlled Trial

Kirwan, Paul

doi:10.25419/rcsi.14381885.v1

PhD thesis final corrected approved version with IP declaration removed.pdf (19.38 MB)

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Topical Glyceryl Trinitrate (GTN) and Eccentric Exercises in the Treatment of Midportion Achilles Tendinopathy (the NEAT trial): a Randomised Double-Blind Placebo-Controlled Trial

thesis

posted on 2022-03-10, 15:57 authored by Paul Kirwan

Eccentric exercise is recommended in the management of Achilles tendinopathy; however, a high proportion of patients with Achilles tendinopathy do not achieve a satisfactory outcome in response to exercise. Nitric oxide has been identified as an important chemical messenger in tendinopathy. Several studies have shown beneficial effect from glyceryl trinitrate (GTN) supplementation to deliver Nitric Oxide to aid recovery from tendinopathy. However, two randomised controlled trials (RCTs) have investigated GTN in Achilles tendinopathy to date, reporting conflicting results. This RCT was undertaken to determine the clinical effectiveness of GTN when combined with eccentric exercise in the treatment of midportion Achilles tendinopathy.

A total of 76 people with Achilles tendinopathy were recruited and randomised to one of two groups: 1)GTN and eccentric exercises (n=37) or 2) placebo ointment and eccentric exercise(n=39). Both groups performed the eccentric exercise twice daily for 12 weeks and applied topical GTN or placebo ointment daily for 24 weeks. All participants were assessed at baseline and at 6,12 and 24 weeks with the primary outcome, the Victorian Institute of Sport Assessment –Achilles (VISA-A), along with a selection of secondary outcome measures.

Ethical approval was obtained from the relevant committees. Data were analysed according to the intention-to-treat analysis to determine between-group differences at week 6, 12 and 24.

Results for the primary study aim showed no significant difference between the GTN and placebo groups at any timepoint for the VISA-A scores. No significant benefit from GTN use was found in any of the secondary outcome measures. Significant improvement in VISA-A scores, and secondary outcomes occurred in both groups, except for structural changes on ultrasound, which remained unchanged.

Daily topical GTN in addition to an eccentric exercise programme does not improve outcomes compared to placebo ointment and an eccentric programme in patients with chronic Achilles tendinopathy.

Funding

Health Research Board

History

First Supervisor

Dr. Helen French

Second Supervisor

Prof. Trevor Duffy

Comments

Submitted for the Award of Doctor of Philosophy to the Royal College of Surgeons in Ireland, 2021.

Published Citation

Kirwan P. Topical Glyceryl Trinitrate (GTN) and Eccentric Exercises in the Treatment of Midportion Achilles Tendinopathy (the NEAT trial): a Randomised Double-Blind Placebo-Controlled Trial [PhD Thesis] Dublin: Royal College of Surgeons in Ireland; 2021