Background Topical glyceryl trinitrate (GTN) treatment has previously demonstrated short-term efficacy in the treatment of lateral epicondylosis. No long-term follow-up has been performed.

Hypothesis Benefits from topical GTN persist 5 years after the cessation of therapy.

Study design A prospective comparative study.

Methods A follow-up study of 58 patients treated with 6 months of topical GTN or placebo, combined with a tendon rehabilitation programme, was performed 5 years after discontinuation of therapy. Assessment included patient-rated pain scores, clinically assessed lateral epicondylar and proximal common extensor tendon tenderness, hand-held dynamometer measurement of resisted third finger metacarpophalangeal extension with a fully extended elbow (Maudsley's test) and wrist extensor tendon mean peak force using a modified chair pick-up test (the Orthopaedic Research Institute—tennis elbow testing system).

Results Patients in both the GTN group and those in the placebo group had significant improvements in symptoms, clinical signs and provocative functional tests compared with baseline week 0 measures. GTN did not offer any additional clinical benefit over a standard tendon rehabilitation programme at 5 years.

Conclusion While GTN appears to offer short-term benefits up to 6 months in the treatment of lateral epicondylosis, at 5 years there does not appear to be significant clinical benefits when compared with patients undertaking a standard tendon rehabilitation programme alone. This is in contrast to findings of continued benefits at long-term follow-up described in the literature for patients with Achilles tendinopathy treated with GTN.